Fluid machine and thermal cycling system

Abstract

Provided is a fluid machine comprising: a rotation structure which has an impeller; a casing which has a shroud wall; a first member which is provided downstream of the impeller, which is movable relative to the shroud wall, and the amount of protrusion of which with respect to the flow path is variable; and a second member which is capable of adjusting the flow of a fluid toward the impeller and along the shroud wall, upstream of the impeller.

Description

Fluid machinery and heat cycle systems

[0001] This application claims priority to Japanese Patent Application No. 2023-214317, filed on December 19, 2023, the contents of which are incorporated herein by reference.

[0002] Conventionally, turbo compressors equipped with suction vanes are known. In such compressors, the angle of the suction vanes is changed to preliminarily impart an appropriate amount of swirl to the fluid flow on the suction side of the blades.

[0003] Japanese Patent Application Publication No. 05-157095

[0004] It is generally known that, regarding the relationship between the flow rate Q and the head H (QH curve) of a turbo fluid machine, if the head is the same, the flow rate does not change at the same rotation speed. In a conventional fluid machine equipped with suction vanes, it is difficult to adjust the flow rate at the same head without reducing efficiency, and there is a problem in that there is a long time delay between the operation of the suction vane and the actual change in flow rate.

[0005] One aspect of the present disclosure aims to provide a fluid machine and a thermal cycle system that can adjust the flow rate at the same head without changing the rotation speed of the fluid machine or significantly reducing efficiency, and that can adjust the flow rate quickly and in a short period of time.

[0006] a first member disposed on the shroud wall upstream of the impeller in the first direction and movable relative to the shroud wall, the first member having a variable protrusion amount relative to the shroud wall toward the impeller in the first direction; and a second member disposed on the shroud wall upstream of the impeller in the first direction and capable of adjusting the flow of fluid along the shroud wall toward the impeller in the first direction.

[0007] In a fluid machine according to one aspect of the present disclosure, the second member has an upstream surface located upstream of the second member and a downstream surface located downstream of the second member, and the second member may be configured to reduce the flow rate of the fluid flowing downstream of the downstream surface, of the fluid flowing along the shroud wall toward the impeller, more than the flow rate of the fluid flowing toward the upstream surface.

[0008] In a fluid machine according to one aspect of the present disclosure, the second member may be movable relative to the shroud wall in the radial direction of the flow path at a cross section of the flow path parallel to a direction perpendicular to the first direction, and the second member may be configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by moving relative to the shroud wall.

[0009] In a fluid machine according to one aspect of the present disclosure, the second member may have an elastic member that forms part of the shroud wall, and by deforming the elastic member, the second member may be configured to reduce the flow rate of the fluid in the vicinity of the shroud wall.

[0010] In a fluid machine according to one aspect of the present disclosure, the second member has an upstream protrusion arranged on the inner wall of the flow path upstream in the first direction, and a downstream protrusion arranged on the inner wall of the flow path downstream of the upstream protrusion in the first direction, and the upstream protrusion and the downstream protrusion are rotatable relative to each other in the circumferential direction of the flow path in a cross section of the flow path parallel to a direction perpendicular to the first direction, and the second member may be configured to reduce the flow rate of the fluid in the vicinity of the shroud wall due to the relative rotation of the upstream protrusion and the downstream protrusion.

[0011] In a fluid machine according to one aspect of the present disclosure, the second member may have an axial portion extending in a direction intersecting the radial direction of the flow path in a cross section of the flow path parallel to a direction perpendicular to the first direction and in a direction intersecting the first direction, and the second member may be configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by rotating around the axial portion.

[0012] In a fluid machine according to one aspect of the present disclosure, the second member may have an axial portion extending radially of the flow path in a cross section of the flow path parallel to a direction perpendicular to the first direction, and the second member may be configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by rotating around the axial portion.

[0013] In a fluid machine according to one aspect of the present disclosure, the impeller may have an impeller inlet located upstream of the impeller in the flow path and communicating with the flow path, and the second member may be configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by adjusting the distance between the second member and the impeller inlet in the first direction.

[0014] A fluid machine according to one aspect of the present disclosure includes: a rotating structure including an impeller having a blade main plate and a blade plate; and a rotating shaft that rotatably supports the impeller; a casing that rotatably houses the rotating structure and has a shroud wall facing the blade plate, a main plate side wall facing the blade main plate, an inlet through which a fluid flows, and an outlet through which the fluid flows; a flow path through which at least a portion of the fluid flows in a first direction from the inlet to the outlet; and a first member that is disposed downstream of the impeller between the main plate side wall and the shroud wall, is movable relative to the shroud wall, has a variable amount of protrusion into the flow path near the downstream end of the impeller, and has a protrusion that protrudes toward the upstream side in the first direction.

[0015] In the fluid machine according to one aspect of the present disclosure, the first member may be disposed at a position radially spaced from the rotating shaft when viewed in an axial direction in which the rotating shaft extends.

[0016] In the fluid machine according to one aspect of the present disclosure, the first member may have an annular shape when viewed in the axial direction.

[0017] In the fluid machine according to one aspect of the present disclosure, the first member may have a circular shape, an oval shape, an elliptical shape, or a polygonal shape when viewed in the axial direction.

[0018] In the fluid machine according to one aspect of the present disclosure, the first member may have a non-annular shape when viewed in the axial direction.

[0019] In a fluid machine according to one aspect of the present disclosure, when viewed in the axial direction, the first member has a plurality of divided portions arranged radially from the rotating shaft, and the plurality of divided portions may be spaced apart along the circumferential direction of the first member.

[0020] In a fluid machine according to one aspect of the present disclosure, the first member has the plurality of divided portions and gap portions in the circumferential direction where the plurality of divided portions are not formed, and if the area ratio of the first member in the annular shape where the gap portions are not formed, as viewed in the axial direction, is 1.0, the total area ratio of the gap portions formed along the circumferential direction, as viewed in the axial direction, may be 0.2 or less.

[0021] In a fluid machine according to one aspect of the present disclosure, the first member has a protrusion protruding toward the upstream side in the first direction and a base extending in the extension direction of the first member, and the protrusion has a first extension portion facing the main plate side wall, and the first extension portion may be provided on a part of the base and extend from the base toward the impeller.

[0022] In a fluid machine according to one aspect of the present disclosure, the first member may have a second extension portion opposite the first extension portion, the base portion may have a storage area that is housed in the shroud wall, and the second extension portion may be provided in the storage area.

[0023] In a fluid machine according to one aspect of the present disclosure, the first member has a protrusion protruding toward the upstream side in the first direction and a base extending in the extension direction of the first member, the base having a base upstream surface facing the impeller, and the protrusion may have a recess provided on the base upstream surface.

[0024] In the fluid machine according to an aspect of the present disclosure, the cross-sectional shape of the recessed portion may have at least one of a curved portion and a corner.

[0025] In a fluid machine according to one aspect of the present disclosure, the first member may have a base extending in the extension direction of the first member, and the base may have a base upstream surface facing the impeller, a base downstream surface opposite the base upstream surface, and a through hole provided in the base so as to extend from the base upstream surface toward the base downstream surface.

[0026] In a fluid machine according to one aspect of the present disclosure, the first member has a tip portion that is located at the farthest end of the first member protruding into the flow path, and the tip portion may be positionable at a minimum position where the first member is accommodated inside the shroud wall and the amount of protrusion of the first member is minimum, a maximum position where the amount of protrusion of the first member protruding from the shroud wall toward the flow path is maximum, and an intermediate position between the maximum position and the minimum position.

[0027] In a fluid machine according to one aspect of the present disclosure, when the tip portion is positioned at the minimum position, the fluid may flow through the flow path from the inlet to the outlet without colliding with the first member.

[0028] In a fluid machine according to one aspect of the present disclosure, when the tip portion is positioned at the maximum position or the intermediate position, a first region, a second region, and a third region are created in the flow path between the impeller and the shroud wall, and in the first region, the fluid flows through the flow path from the inlet to the outlet without colliding with the first member, in the second region, the fluid flows toward the first member and collides with the first member, and in the third region, the fluid that collides with the first member flows in a second direction opposite to the first direction.

[0029] In a fluid machine according to one aspect of the present disclosure, the impeller has an impeller outlet located downstream of the impeller in the flow path, the impeller has an impeller inlet located upstream of the impeller in the flow path and communicating with the flow path, the impeller has a partition member facing the shroud wall, the partition member having a blade opening located closer to the impeller inlet than the impeller outlet, the partition member being located at a boundary between the second region and the third region, and the fluid may flow from the third region to the second region via the blade opening.

[0030] In a fluid machine according to one aspect of the present disclosure, the impeller has an impeller outlet located downstream of the impeller in the flow path, and with regard to the angle of the blade in the second region near the impeller outlet, when the angle of the blade is set to 0 degrees relative to the radial direction of the impeller and is a positive value relative to the rotation direction of the impeller, the maximum value of the angle of the blade may be 0 degrees or a positive value.

[0031] In a fluid machine according to one aspect of the present disclosure, the impeller has an impeller outlet located downstream of the impeller in the flow path, and with regard to the angle of the blade in the third region near the impeller outlet, when the angle of the blade is set to 0 degrees relative to the radial direction of the impeller and the angle of the blade is set to a positive value relative to the rotation direction of the impeller, the minimum value of the angle of the blade may be 0 degrees or a negative value.

[0032] In a fluid machine according to one aspect of the present disclosure, the first member has a base extending in the extension direction of the first member, and the base has a base upstream surface facing the impeller, a base downstream surface opposite the base upstream surface, and a through hole provided in the base so as to extend from the base upstream surface toward the base downstream surface, and a portion of the fluid flowing through the flow path may flow through the through hole in a second direction opposite to the first direction, reach the base upstream surface, and join the fluid flowing in the second region.

[0033] In a fluid machine according to one aspect of the present disclosure, the fluid flowing through the through hole in the second direction and the fluid flowing in the second region merge to generate a merged fluid at the upstream surface of the base, and the merged fluid may accelerate the flow of the fluid in the third region.

[0034] The fluid machine according to one aspect of the present disclosure may include a first drive unit coupled to the first member and configured to move the first member relative to the shroud wall.

[0035] The fluid machine according to one aspect of the present disclosure may include a second drive unit coupled to the second member and configured to move the second member relative to the shroud wall.

[0036] A fluid machine according to one aspect of the present disclosure may have a first drive unit connected to the first member and moving the first member relative to the shroud wall, and the first drive unit and the second drive unit may move the first member and the second member so that the first member and the second member are synchronized with each other.

[0037] A fluid machine according to one aspect of the present disclosure may have a drive unit that moves the first member and the second member, the drive unit being connected to the first member and moving the first member relative to the shroud wall, the drive unit being connected to the second member and moving the second member relative to the shroud wall, and the drive unit moving the first member and the second member so that the first member and the second member are synchronized with each other.

[0038] In the fluid machine according to one aspect of the present disclosure, the impeller may have a side plate joined to the blade plate so as to be spaced apart from the main blade plate, and the side plate may face the shroud wall.

[0039] A heat cycle system according to one aspect of the present disclosure includes the fluid machine according to the above aspect.

[0040] According to one aspect of the present disclosure, the flow rate at the same head can be adjusted without changing the rotation speed of the fluid machine and without significantly reducing efficiency, and the flow rate can be adjusted quickly and in a short time.

[0041] FIG. 1 is a cross-sectional view showing a fluid machine according to a first embodiment of the present disclosure; FIG. 1 is a cross-sectional view showing a main part of the fluid machine according to the first embodiment of the present disclosure, illustrating driving of a first member and a second member; FIG. 1 is a cross-sectional view showing a main part of the fluid machine according to the first embodiment of the present disclosure, illustrating driving of the first member and the second member; FIG. 2 is a cross-sectional view showing a main part of the fluid machine according to the first embodiment of the present disclosure, illustrating a structure of the first member as viewed from an axial direction; FIG. 3 is a cross-sectional view showing a modified example of the first member in the fluid machine according to the first embodiment of the present disclosure, illustrating a structure of the first member as viewed from an axial direction; FIG. 4 is a cross-sectional view showing a first modified example of the second member in the fluid machine according to the first embodiment of the present disclosure; FIG. 5 is a cross-sectional view showing a second modified example of the second member in the fluid machine according to the first embodiment of the present disclosure; FIG. 6 is a cross-sectional view showing a third modified example of the second member in the fluid machine according to the first embodiment of the present disclosure; FIG. 7 is a perspective view showing a third modified example of the second member in the fluid machine according to the first embodiment of the present disclosure; FIG. 8 is a perspective view showing a third modified example of the second member in the fluid machine according to the first embodiment of the present disclosure; FIG. 1 is a cross-sectional view showing a sixth modified example of the second member in the fluid machine according to the first embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a seventh modified example of the second member in the fluid machine according to the first embodiment of the present disclosure. FIG. 3 is a cross-sectional view showing an eighth modified example of the second member in the fluid machine according to the first embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing a main part of the fluid machine according to the second embodiment of the present disclosure, and is a view illustrating driving of the first member. FIG. 5 is a cross-sectional view showing a first modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 6 is a cross-sectional view showing a second modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 7 is a perspective view showing a third modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 8 is a perspective view showing a fourth modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 9 is a cross-sectional view showing a fifth modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 10 is a cross-sectional view showing a sixth modified example of the first member in the fluid machine according to the second embodiment of the present disclosure.10 is a cross-sectional view showing a seventh modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 11 is a cross-sectional view partially showing an eighth modified example of the first member in the fluid machine according to the second embodiment of the present disclosure. FIG. 12 is a perspective view partially showing a general blade plate in a fluid machine, the view being for explaining the definition of the angle of the blade plate and a velocity triangle. FIG. 13 is a cross-sectional view showing the impeller in the fluid machine according to the third embodiment of the present disclosure, the view being for explaining regions generated in the blades. FIG. 14 is a graph for explaining the angle of the blade plate in the fluid machine according to the third embodiment of the present disclosure. FIG. 15 is a view for explaining the effects of the fluid machine according to the third embodiment of the present disclosure. FIG. 16 is a view for explaining the effects of the fluid machine according to the third embodiment of the present disclosure. FIG. 17 is a view for explaining the effects of the fluid machine according to the third embodiment of the present disclosure. FIG. 18 is a cross-sectional view showing the impeller in the fluid machine according to the fourth embodiment of the present disclosure, the view being for explaining a partition member provided in the impeller. FIG. 19 is a cross-sectional view showing a modified example of the impeller in the fluid machine according to the fourth embodiment of the present disclosure. FIG. 19 is a cross-sectional view showing a modified example of the impeller in the fluid machine according to the fifth embodiment of the present disclosure. FIG. 19 is a cross-sectional view showing a modified example of the impeller in the fluid machine according to the fifth embodiment of the present disclosure. 10 is a schematic diagram showing an example of a heat cycle system according to a sixth embodiment of the present disclosure. FIG. 11 is a cycle diagram showing a state change of a working fluid in the heat cycle system according to the sixth embodiment of the present disclosure on a pressure-enthalpy diagram.

[0042] A fluid machine and a thermal cycle system according to an embodiment of the present disclosure will be described with reference to the drawings. In the description of the embodiment, components having the same or similar functions are designated by the same reference numerals. Duplicate descriptions of those components may be omitted. The drawings are schematic or conceptual representations of the thermal cycle system.

[0043] In the description of the embodiments, ordinal numbers such as "first," "second," and "third" may be used. These ordinal numbers do not indicate the number of components described with the ordinal numbers. Ordinal numbers may be used to indicate that each of a plurality of components is a separate component.

[0044] The term "opposite" indicates the positional relationship between two components. This positional relationship not only means that the two components are facing each other, but also means that another component is interposed between the two components. The same interpretation applies to the terms "provided," "disposed," and "connected."

[0045] In describing the fluid machine, the terms "axial direction AD," "radial direction RD," "circumferential direction CD," "first direction FD," and "second direction SD" are used as directional terms. The axial direction AD is the direction in which the rotation shaft 22 of the rotating structure 20 extends. The radial direction RD is the direction from the center of the blade main plate 24 of the rotating structure 20 toward the outer periphery. The circumferential direction CD is the direction along the outer periphery of the blade main plate 24 of the rotating structure 20. The first direction FD is the direction in which the fluid FL flows from the inlet 33 to the outlet 34 of the casing 30. The second direction SD is the direction opposite to the first direction FD. The terms "axial direction AD," "radial direction RD," "circumferential direction CD," "first direction FD," and "second direction SD" are terms used to describe the relative positions of multiple components constituting each of the fluid machines, or the shape and structure of each of the multiple components, and do not define the attitude of each of the fluid machines.

[0046] 1 , a fluid machine 10 includes a rotating structure 20, a casing 30, a flow path FP, a first member 40, a second member 50, a first drive unit D1, and a second drive unit D2. The fluid machine 10 according to this embodiment is a horizontal shaft pump equipped with a so-called open impeller. Note that the structure of the fluid machine 10 can also be applied to known pumps and compressors, such as axial flow pumps, mixed flow pumps, and centrifugal pumps.

[0047] <Rotating structure> The rotating structure 20 has an impeller 21, a rotating shaft 22, and a support member 23. The impeller 21 has a main blade plate 24 and a plurality of blade plates 25. The main blade plate 24 is a member that supports the blade plates 25. The main blade plate 24 and the plurality of blade plates 25 form a so-called impeller. The rotating structure 20 is configured to rotate inside the casing 30 around the axial direction AD.

[0048] Furthermore, the impeller 21 has an impeller inlet 26 and an impeller outlet 27. The impeller inlet 26 is located upstream of the impeller 21 in the flow path FP. The impeller inlet 26 is connected to the flow path FP. The impeller inlet 26 is the portion of the rotating structure 20 where the fluid FL flows into the impeller 21. The impeller outlet 27 is located downstream of the impeller 21 in the flow path FP. The impeller outlet 27 is connected to the flow path FP. The impeller outlet 27 is the portion of the rotating structure 20 where the fluid FL flows out of the impeller 21.

[0049] <Vane Plate> The plurality of vane plates 25 are provided on the main blade plate 24 so as to extend from the main blade plate 24 in the axial direction AD. The plurality of vane plates 25 are lined up in the circumferential direction CD of the main blade plate 24. The shape of each of the plurality of vane plates 25 is not particularly limited. Each of the plurality of vane plates 25 may have a curved surface extending from the central region of the main blade plate 24 toward the outer circumferential region. The height of each of the plurality of vane plates 25 from the main blade plate 24 may be set to vary in the radial direction RD. The shape of each of the plurality of vane plates 25 may have a curved surface that varies in the radial direction RD.

[0050] The impeller 21 is fixed to the rotary shaft 22. The impeller 21 can rotate as the rotary shaft 22 rotates. The support member 23 is disposed between the casing 30 and the rotary shaft 22. The support member 23 includes a bearing and a seal member. The bearing rotatably supports the rotary shaft 22. The seal member is, for example, a mechanical seal. The rotary shaft 22 is connected to a drive unit (not shown). When power generated in the drive unit is transmitted to the rotary shaft 22, the rotary shaft 22 rotates, and the impeller 21 rotates as the rotary shaft 22 rotates. The drive unit is, for example, a known motor.

[0051] <Casing> The casing 30 has a shroud wall 31, a main plate side wall 32, an inlet 33, and an outlet 34. The shroud wall 31 rotatably houses the rotating structure 20 and faces the blade plate 25. The main plate side wall 32 faces the blade main plate 24. The fluid FL flows into the inlet 33. In other words, the inlet 33 is an intake port that draws the fluid FL toward the casing 30. The fluid FL flows out from the outlet 34. In other words, the outlet 34 is a discharge port that discharges the fluid FL from the casing 30.

[0052] 2A and 2B , the casing 30 has a first member accommodating groove 35 provided in the shroud wall 31. The first member 40 is accommodated in the first member accommodating groove 35 and is movable in the direction in which the first member accommodating groove 35 extends.

[0053] <Flow path> The flow path FP is a space between the inlet 33 and the outlet 34 in the casing 30. The blade main plate 24, the plurality of blade plates 25, at least a part of the first member 40, and at least a part of the second member 50 are arranged in this space. At least a part of the fluid FL flows through the flow path FP in a first direction FD from the inlet 33 toward the outlet 34.

[0054] <First Member> The first member 40 is provided downstream of the impeller 21 between the main plate sidewall 32 and the shroud wall 31. In other words, the first member 40 is located in the downstream region DR downstream of the impeller 21. The first member 40 is movable relative to the shroud wall 31. A protrusion amount AP of the first member 40 with respect to the flow path FP near the downstream end of the impeller 21 is variable. In other words, a protrusion amount AP of the first member 40 with respect to the flow path FP near the impeller outlet 27 is variable.

[0055] As shown in FIGS. 2A and 2B , the first member 40 has a tip portion 41, which is the most distal portion of the first member 40 protruding into the flow path FP. With respect to the protrusion amount AP of the first member 40 relative to the flow path FP, the tip portion 41 of the first member 40 can be positioned at a minimum position P0, a maximum position PX, or an intermediate position PM. Here, the minimum position P0 is the position where the first member 40 is accommodated inside the shroud wall 31 and the protrusion amount AP of the first member 40 is minimum. With respect to the position of the tip portion 41 relative to the shroud wall 31, the minimum position P0 may be arbitrarily set. For example, the protrusion amount AP may be defined as being positioned at the minimum position P0 when the positions of the shroud wall 31 and the tip portion 41 coincide with each other as viewed in the first direction FD. Alternatively, the protrusion amount AP may be defined as being positioned at the minimum position P0 when the tip portion 41 is recessed from the shroud wall 31 as viewed in the first direction FD. Alternatively, the state in which the tip end 41 slightly protrudes from the shroud wall 31 as viewed in the first direction FD may be defined as the minimum protrusion amount AP being located at P0. The maximum position PX is the position at which the protrusion amount AP of the first member 40 protruding from the shroud wall 31 toward the flow path FP is maximum.

[0056] The intermediate position PM is a position that is arbitrarily set between the maximum position PX and the minimum position P0. The intermediate position may be exactly the center position between the maximum position PX and the minimum position P0, or may be a position that is shifted from the center position. In other words, the intermediate position may be a position that is closer to the maximum position PX than the minimum position P0. The intermediate position may also be a position that is closer to the minimum position P0 than the maximum position PX. In other words, since the intermediate position is a position of the tip portion 41 that is displaceable between the maximum position PX and the minimum position P0, the intermediate position may also be referred to as a variable position.

[0057] As shown in FIG. 3A , the first member 40 is disposed at a position spaced apart from the rotating shaft 22 in the radial direction RD as viewed in the axial direction AD. Note that FIG. 3A is a diagram for explaining the relative positions of the first member 40 and the rotating shaft 22. In FIG. 3A , members constituting the fluid machine 10 other than the first member 40 and the rotating shaft 22 are omitted. In the example shown in FIG. 3A , the first member 40 has an annular shape as viewed in the axial direction AD. In other words, the first member 40 has a circular shape. When the first member 40 has an annular shape, the shape of the first member 40 is not limited to a circular shape and may have an oval shape, an elliptical shape, or a polygonal shape. Furthermore, the first member 40 may have a non-annular shape as viewed in the axial direction AD.

[0058] <Second Member> The second member 50 is disposed on the shroud wall 31 upstream of the impeller 21 in the first direction FD. In other words, the second member 50 is located in the upstream region UR upstream of the impeller 21. The second member 50 can adjust the flow of the fluid FL along the shroud wall 31 toward the impeller 21 in the first direction FD.

[0059] Specifically, by driving the second member 50, the second member 50 can generate stagnation in the fluid FL flowing near the shroud wall 31. In other words, it is possible to suppress the smooth flow of the fluid FL near the shroud wall 31. Furthermore, by adjusting the amount of movement of the second member 50, it is possible to adjust the degree of stagnation generated in the fluid FL.

[0060] In other words, the second member 50 has an upstream surface 50U located upstream of the second member 50 and a downstream surface 50L located downstream of the second member 50. The second member 50 can adjust the flow rate of the fluid FL flowing toward the upstream surface 50U and the flow rate of the fluid FL flowing downstream of the downstream surface 50L, among the fluid FL flowing along the shroud wall 31 toward the impeller 21. In particular, the second member 50 is configured to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L, among the fluid FL flowing along the shroud wall 31 toward the impeller 21, compared to the flow rate of the fluid FL flowing toward the upstream surface 50U. "Adjusting the flow rate" includes the meanings of "increasing the flow rate," "reducing the flow rate," and "adjusting the flow rate ratio." In addition, the following explanation will mainly focus on reducing the flow rate of the fluid FL flowing downstream of the downstream surface 50L in order to generate the "reflux of the fluid FL" described below, but it is also possible to increase the flow rate of the fluid FL downstream of the downstream surface 50L where the flow rate has been reduced.

[0061] Specifically, the fluid FL flowing around the second member 50 will be described. As the fluid machine 10 is driven, the fluid FL flows from the inlet 33 toward the outlet 34. A portion of the fluid FL flowing toward the second member 50 flows toward the upstream surface 50U and collides with the upstream surface 50U. The fluid FL that collides with the upstream surface 50U forms a flow away from the shroud wall 31. The fluid FL that forms such a flow merges with the flow of the other fluid FL that has not collided with the upstream surface 50U, passes over the second member 50, and flows toward the impeller inlet 26. In this flow of the fluid FL upstream of the second member 50, the flow rate of the fluid FL flowing through the second member 50 so as to collide with the upstream surface 50U is the "flow rate QU of the fluid FL flowing toward the upstream surface 50U." The fluid FL flowing toward the upstream surface 50U is, for example, a fluid flowing through the region indicated by the symbol UP in FIGS. 2A and 2B .

[0062] Next, of the fluid FL flowing from the inlet 33 toward the outlet 34, a portion of the fluid FL immediately after passing over the second member 50 forms a flow that follows the downstream surface 50L and approaches the shroud wall 31. The fluid FL that forms such a flow flows downstream of the downstream surface 50L. In such a flow of the fluid FL downstream of the second member 50, the flow rate of the fluid FL that flows along the downstream surface 50L and approaches the shroud wall 31 is the "flow rate QL of the fluid FL flowing downstream of the downstream surface 50L." Furthermore, the fluid FL flowing downstream of the downstream surface 50L is, for example, a fluid that flows in the region indicated by the symbol LP in FIGS. 2A and 2B .

[0063] By driving the second member 50, the second member 50 can reduce the "flow rate QL of the fluid FL flowing downstream of the downstream surface 50L" to be less than the "flow rate QU of the fluid FL flowing toward the upstream surface 50U." In other words, the second member 50 can reduce the flow rate QL of the fluid FL flowing between the downstream surface 50L and the impeller inlet 26 (QU>QL).

[0064] <First Drive Unit and Second Drive Unit> The first drive unit D1 is coupled to the first member 40 and configured to move the first member 40 relative to the shroud wall 31. The second drive unit D2 is coupled to the second member 50 and configured to move the second member 50 relative to the shroud wall 31. The structure of each of the first drive unit D1 and the second drive unit D2 is not particularly limited. For example, they may be motors driven by electricity, or valves that use the pressure of the fluid FL flowing through the fluid machine 10 to drive each of the first member 40 and the second member 50.

[0065] The first driving unit D1 and the second driving unit D2 may move the first member 40 and the second member 50 so that the first member 40 and the second member 50 are synchronized with each other.

[0066] <Operations and Effects> Next, operations and effects of the fluid machine 10 according to the first embodiment will be described. In the fluid machine 10, as the rotating structure 20 rotates, the plurality of blades 25 push out the fluid FL, and the fluid FL flows through the flow path FP from the inlet 33 to the outlet 34 of the casing 30. In this state, the first member 40 moves, and the protrusion amount AP of the first member 40 with respect to the flow path FP is adjusted. In addition, the second member 50 moves, and the degree of stagnation occurring in the fluid FL is adjusted.

[0067] <Adjusting the amount of protrusion by moving the first member> <Disposition of tip portion at minimum position> First, a case will be described where the tip portion 41 of the first member 40 is disposed at the minimum position P0, as shown in Fig. 2A . In this case, the fluid FL flows through the flow path FP from the inlet 33 toward the outlet 34 without colliding with the first member 40. Specifically, if the flow rate of the fluid FL supplied to the inlet 33 of the fluid machine 10 is 100%, the flow rate of the fluid FL discharged from the outlet 34 of the fluid machine 10 is also 100%.

[0068] <Movement of Tip Portion from Minimum Position to Intermediate Position> A case will be described in which the tip portion 41 of the first member 40 moves from the minimum position P0 to the intermediate position PM by adjusting the protrusion amount AP. As shown in FIG. 2B , when the tip portion 41 of the first member 40 is positioned at the intermediate position PM, a first region R1, a second region R2, and a third region R3 are formed in the flow path FP between the impeller 21 and the shroud wall 31. In the first region R1, the fluid FL flows through the flow path FP from the inlet 33 to the outlet 34 without colliding with the first member 40. In the second region R2, the fluid FL flows toward the first member 40 and collides with the first member 40 at a flow rate lower than when the tip portion 41 is positioned at the maximum position PX. In the third region R3, the fluid FL that collides with the first member 40 flows in the second direction SD, opposite the first direction FD, at a flow rate lower than when the tip portion 41 is positioned at the maximum position PX.

[0069] The operation when the tip portion 41 moves from the minimum position P0 to the intermediate position PM will be specifically described. When the tip portion 41 of the first member 40 is positioned at the minimum position P0, the flow rate of the fluid FL sucked into the inlet 33 of the fluid machine 10 is assumed to be 100%. In this case, the flow rate of the fluid FL discharged from the outlet 34 of the fluid machine 10 is approximately 90%. The remaining 10% of the flow rate collides with the first member 40. Because the first member 40 is located radially outward of the impeller outlet 27 in the radial direction RD, the velocity of the fluid FL decreases and the pressure of the fluid FL increases due to the law of conservation of angular momentum. Furthermore, because the first member 40 is located downstream of the impeller outlet 27 in the first direction FD, the flow of the fluid FL is hindered in the third region R3 compared to when the first member 40 is positioned at the minimum position P0. This reduces the pressure at the impeller outlet 27. This results in a pressure difference between the second region R2 and the third region R3. Therefore, the fluid FL flowing in the first direction FD in the second region R2 collides with the first member 40, flows in the second direction SD, and flows into the third region R3. In other words, a reflux of the fluid FL occurs in the second region R2 and the third region R3. As a result, the flow rate of the fluid FL sucked from the inlet 33 of the fluid machine 10 becomes 90% of the flow rate when the tip end 41 of the first member 40 is positioned at the minimum position P0. Therefore, the flow rate of the fluid machine 10 can be reduced.

[0070] The reflux of the fluid FL in the second region R2 and the third region R3 will be described in more detail. In the following description, the fluid FL flowing in the first direction FD in the first region R1 will be referred to as fluid FL1, the fluid FL flowing in the first direction FD in the second region R2 will be referred to as fluid FL2, and the fluid FL flowing in the second direction SD in the third region R3 will be referred to as fluid FL3. The fluid FL3 flowing in the second direction SD in the third region R3 at the impeller outlet 27 performs work on the impeller 21 in the third region R3, and as the pressure of the fluid FL3 decreases, the fluid FL3 flows through the third region R3 toward the impeller inlet 26. Before reaching the impeller inlet 26, the fluid FL3 enters the second region R2 and flows through the second region R2 as fluid FL2. Here, when the fluid FL3 is converted into the fluid FL2, that is, when the fluid FL2 flows again in the first direction FD in the second region R2, the fluid FL2 receives work from the impeller 21, and the pressure of the fluid FL2 increases. In other words, a reflux of the fluid FL occurs in the second region R2 and the third region R3. Therefore, the flow rate of the fluid FL sucked from the inlet 33 of the fluid machine 10 is 90% of that when the tip end 41 of the first member 40 is positioned at the minimum position P0.

[0071] Furthermore, the above-described reflux effect is promoted by the second member 50. The second member 50 reduces the flow rate of the fluid FL flowing downstream of the downstream surface 50L to be less than the flow rate of the fluid FL flowing toward the upstream surface 50U. Therefore, the second member 50 reduces the flow rate of the fluid FL supplied between the downstream surface 50L and the impeller 21. As a result, the second member 50 prevents the fluid FL taken in through the inlet 33 of the fluid machine 10 from entering the third region R3. The second member 50 promotes the generation of the second region R2 and the third region R3 downstream of the downstream surface 50L. Furthermore, since the first member 40 and the second member 50 are provided in the fluid machine 10, a reflux generation region is generated between the first member 40 and the second member 50, and the effects of the fluids FL2 and FL3 in the second region R2 and the third region R3 described above are promoted in the reflux generation region.

[0072] <Movement of tip portion from intermediate position to minimum position> A case will be described where the tip portion 41 of the first member 40 moves from the intermediate position PM to the minimum position P0 by adjusting the protrusion amount AP. The position of the tip portion 41 of the first member 40 returns from the position shown in FIG. 2B in which the tip portion 41 of the first member 40 is positioned at the intermediate position PM to the position shown in FIG. 2A in which the tip portion 41 of the first member 40 is positioned at the minimum position P0.

[0073] Because the fluid FL no longer collides with the first member 40, reflux of the fluid FL in the second region R2 and the third region R3 quickly disappears. Therefore, if the flow rate of the fluid FL sucked in from the inlet 33 of the fluid machine 10 when the tip end 41 of the first member 40 is positioned at the minimum position P0 is set to 100%, the flow rate of the fluid FL discharged from the outlet 34 of the fluid machine 10 will also be 100%. In other words, the 10% of the flow rate that was not flowing due to the decrease in the flow rate of the fluid machine 10 is quickly discharged from the outlet 34, and the 10% of the flow rate is quickly sucked in from the inlet 33. In other words, the flow rate of the fluid FL can be quickly increased.

[0074] <Movement of Tip from Minimum Position to Maximum Position> A case will be described in which the tip 41 of the first member 40 moves from the minimum position P0 to the maximum position PX by adjusting the protrusion amount AP. As shown in FIG. 2B , when the tip 41 of the first member 40 is positioned at the maximum position PX, a first region R1, a second region R2, and a third region R3 are formed in the flow path FP between the impeller 21 and the shroud wall 31. In the first region R1, the fluid FL flows through the flow path FP from the inlet 33 to the outlet 34 without colliding with the first member 40. In the second region R2, the fluid FL flows toward the first member 40 and collides with the first member 40. In the third region R3, the fluid FL that collides with the first member 40 flows in a second direction SD, which is opposite to the first direction FD.

[0075] The operation when the tip portion 41 moves from the minimum position P0 to the maximum position PX will be specifically described. When the tip portion 41 of the first member 40 is positioned at the minimum position P0, the flow rate of the fluid FL sucked into the inlet 33 of the fluid machine 10 is assumed to be 100%. In this case, the flow rate of the fluid FL discharged from the outlet 34 of the fluid machine 10 is approximately 80%. The remaining 20% ​​of the flow rate collides with the first member 40. Because the first member 40 is located radially outward of the impeller outlet 27 in the radial direction RD, the velocity of the fluid FL decreases and the pressure of the fluid FL increases due to the law of conservation of angular momentum. Furthermore, because the first member 40 is located downstream of the impeller outlet 27 in the first direction FD, the flow of the fluid FL is hindered in the third region R3 compared to when the first member 40 is positioned at the minimum position P0. This reduces the pressure at the impeller outlet 27. This results in a pressure difference between the second region R2 and the third region R3. Therefore, the fluid FL flowing in the first direction FD in the second region R2 collides with the first member 40, flows in the second direction SD, and flows into the third region R3. In other words, a reflux of the fluid FL occurs in the second region R2 and the third region R3. As a result, the flow rate of the fluid FL sucked from the inlet 33 of the fluid machine 10 becomes 80% of the flow rate when the tip end 41 of the first member 40 is positioned at the minimum position P0. Therefore, the flow rate of the fluid machine 10 can be reduced.

[0076] The reflux of the fluid FL in the second region R2 and the third region R3 will be described in more detail. The fluid FL3 flowing in the second direction SD in the third region R3 of the impeller outlet 27 performs work on the impeller 21 in the third region R3. As the pressure of the fluid FL3 decreases, the fluid FL3 flows through the third region R3 toward the impeller inlet 26. Before reaching the impeller inlet 26, the fluid FL3 enters the second region R2 and flows through the second region R2 as fluid FL2. Here, when the fluid FL3 is converted into fluid FL2, that is, when the fluid FL2 flows again in the first direction FD in the second region R2, the work of the impeller 21 is performed on the fluid FL2, and the pressure of the fluid FL2 increases. In other words, reflux of the fluid FL occurs in the second region R2 and the third region R3. Therefore, the flow rate of the fluid FL sucked in from the inlet 33 of the fluid machine 10 is 80% of that when the tip end 41 of the first member 40 is located at the minimum position P0.

[0077] Furthermore, the above-described reflux effect is promoted by the second member 50. The second member 50 reduces the flow rate of the fluid FL flowing downstream of the downstream surface 50L to be less than the flow rate of the fluid FL flowing toward the upstream surface 50U. Therefore, the second member 50 reduces the flow rate of the fluid FL supplied between the downstream surface 50L and the impeller 21. As a result, the second member 50 prevents the fluid FL taken in through the inlet 33 of the fluid machine 10 from entering the third region R3. The second member 50 promotes the generation of the second region R2 and the third region R3 downstream of the downstream surface 50L. Furthermore, since the first member 40 and the second member 50 are provided in the fluid machine 10, a reflux generation region is generated between the first member 40 and the second member 50, and the effects of the fluids FL2 and FL3 in the second region R2 and the third region R3 described above are promoted in the reflux generation region.

[0078] <Movement of Tip Portion from Maximum Position to Minimum Position> A case will be described in which the tip portion 41 of the first member 40 moves from the maximum position PX to the minimum position P0 by adjusting the protrusion amount AP. The position of the tip portion 41 of the first member 40 returns from the position shown in FIG. 2B in which the tip portion 41 of the first member 40 is positioned at the maximum position PX to the position shown in FIG. 2A in which the tip portion 41 of the first member 40 is positioned at the minimum position P0.

[0079] Because the fluid FL no longer collides with the first member 40, backflow of the fluid FL in the second region R2 and the third region R3 quickly disappears. Therefore, if the flow rate of the fluid FL sucked in from the inlet 33 of the fluid machine 10 when the tip end 41 of the first member 40 is positioned at the minimum position P0 is set to 100%, the flow rate of the fluid FL discharged from the outlet 34 of the fluid machine 10 will also be 100%. In other words, the 20% of the flow rate that was not flowing due to the decrease in the flow rate of the fluid machine 10 is quickly discharged from the outlet 34, and the 20% of the flow rate is quickly sucked in from the inlet 33. In other words, the flow rate of the fluid FL can be quickly increased.

[0080] According to the above-described embodiment, the protrusion amount AP of the first member 40 with respect to the flow path FP can be adjusted by moving the first member 40 relative to the shroud wall 31. This makes it possible to adjust the flow rate at the same head without changing the rotation speed of the fluid machine or significantly reducing efficiency, and allows for fast flow rate adjustment in a short time.

[0081] In the above-described embodiment, the movement of the second member 50 can adjust the degree of stagnation of the fluid FL flowing near the shroud wall 31. Therefore, the degree of obstruction of the flow of the fluid FL in the third region R3 is increased compared to when only the first member 40 is positioned from the minimum position P0 to the intermediate position PM or the maximum position PX, thereby minimizing the degree of stagnation of the fluid FL. This further reduces the pressure of the fluid FL3 in the third region R3 at the impeller outlet 27. The fluid FL2 flowing in the first direction FD in the second region R2 collides with the first member 40, causing the fluid FL2 to flow in the second direction SD through the third region R3, resulting in further reflux of the fluid FL in the second region R2 and the third region R3. This allows the flow rate at the same head to be further adjusted without changing the rotation speed of the fluid machine 10 or significantly reducing efficiency, thereby enabling fast flow rate adjustment in a short time.

[0082] As described above, the fluid machine 10 according to this embodiment, which uses the first member 40 and the second member 50, does not require the use of a costly pre-swirl device using suction vanes as in the conventional technology. In other words, this embodiment achieves the above-described effects at low cost through a simple structure. Furthermore, flow rate adjustment using a pre-swirl device generally involves a reduction in the head required for stable operation because the work performed by the impeller on the fluid is reduced. This often results in a trade-off with a reduction in the operable range. In contrast, this embodiment controls the fluids FL2 and FL3 flowing through the impeller 21 using reflux generated in the second region R2 and the third region R3. Therefore, in principle, there is no reduction in head, and therefore no reduction in the operable range. Therefore, the fluid machine 10 according to this embodiment is superior to a configuration that adjusts the flow rate using a conventional pre-swirl device.

[0083] The degree of flow rate reduction achieved by the fluid machine 10 is not limited to that in the above-described embodiment. That is, the flow rate reduction is not limited to 10% or 20%, and the flow rate can be adjusted by several percent to several tens of percent by adjusting the protrusion amount AP of the first member 40 and adjusting the position of the second member 50.

[0084] <Modification of First Member> Next, a modification of the first member will be described with reference to Fig. 3B. Here, the same members as those described with reference to Figs. 1 to 2B are denoted by the same reference numerals, and their description will be omitted or simplified.

[0085] 3B , when viewed in the axial direction AD, the first member 40A has a plurality of divided portions 42 arranged in the radial direction RD from the rotation axis 22. The plurality of divided portions 42 are arranged along the circumferential direction CD of the first member 40A. Two adjacent divided portions of the plurality of divided portions 42 are spaced apart from each other.

[0086] The first member 40A has a plurality of divided portions 42 and gap portions 43 in the circumferential direction where no divided portions 42 are formed. The gap portions 43 are formed between two adjacent divided portions. If the area ratio of the annular shape of the first member 40A where no gap portions 43 are formed as viewed in the axial direction AD is 1.0, the total area ratio of the gap portions 43 formed along the circumferential direction as viewed in the axial direction AD is 0.2 or less. In other words, since the first member 40A shown in FIG. 3B has eight divided portions 42 and eight gap portions 43, the total area ratio of the eight divided portions 42 is 0.8 or more, and the total area ratio of the eight gap portions 43 is 0.2 or less.

[0087] In the example shown in FIG. 3B , the first member 40A has eight divided portions 42 and eight gap portions 43. The number of divided portions 42 is not limited to eight. The number of divided portions 42 may be seven or less, or nine or more. Furthermore, with regard to the length of the divided portions 42 in the circumferential direction, at least two of the eight divided portions 42 may have the same length. In other words, the eight divided portions 42 may have the same length. At least two of the eight divided portions 42 may have different lengths.

[0088] <Modifications of the Second Member> Next, modifications of the second member will be described with reference to Figures 4A to 4I. Here, the same components as those described with reference to Figures 1 to 2B are given the same reference numerals, and their description will be omitted or simplified. In each of the multiple modifications, the second member is driven by a second drive unit D2. A transmission mechanism for transmitting power or a known conversion mechanism for converting the power transmission direction is provided between the second drive unit D2 and the second member.

[0089] 4A , the casing 30 has a second member accommodating groove 36 provided in the shroud wall 31. The second member 50A is accommodated in the second member accommodating groove 36 and is movable in the radial direction RD, which is the extension direction of the second member accommodating groove 36. In other words, the second member 50A is movable relative to the shroud wall 31 in the radial direction RD of the flow path FP at the cross section of the flow path FP.

[0090] Specifically, the second member 50A has two plate members 50AF and 50AS. Each of the plate members 50AF and 50AS has an end surface 50AE facing the flow path FP. Each of the plate members 50AF and 50AS is housed in the second member housing groove 36 so that the two end surfaces 50AE face each other. Reference numeral 26P denotes the position of the impeller inlet 26.

[0091] Like the second member 50, the second member 50A has an upstream surface 50U and a downstream surface 50L. That is, each of the plate members 50AF and 50AS has an upstream surface 50U and a downstream surface 50L. The second member 50A is configured to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L by moving relative to the shroud wall 31, among the fluid FL flowing along the shroud wall 31 toward the impeller 21, compared to the flow rate of the fluid FL flowing toward the upstream surface 50U. In other words, the second member 50A is configured to reduce the flow rate QL of the fluid FL flowing through the region LP by less than the flow rate QU of the fluid FL flowing through the region UP (QU > QL). That is, the second member 50A is configured to reduce the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set so as to obtain the above-mentioned effect of reflux of the fluid FL.

[0092] Specifically, by moving the second member 50A so that the end face 50AE protrudes from the shroud wall 31, the exposed area of ​​the upstream surface 50U in the flow path FP increases, and the exposed area of ​​the downstream surface 50L in the flow path FP also increases. The flow rate of the fluid FL colliding with the upstream surface 50U increases. This makes it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L more than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0093] In other words, as the second member 50A moves relative to the shroud wall 31, i.e., as the plate members 50AF and 50AS move relative to each other, the distance between the end faces 50AE of the plate members 50AF and 50AS increases or decreases. This makes it possible to adjust the flow area 51 of the fluid FL flowing between the plate members 50AF and 50AS. That is, in a cross section of the flow path FP parallel to the direction PD perpendicular to the first direction FD, i.e., in a cross section of the flow path FP parallel to the radial direction RD, the second member 50A is configured to adjust the flow area 51 of the fluid FL flowing through the flow path FP. Like the second member 50 described above, the second member 50A configured in this manner can adjust the flow of the fluid FL along the shroud wall 31 toward the impeller 21 in the first direction FD. Therefore, by adjusting the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation occurring in the fluid FL.

[0094] <Second Modification of the Second Member> As shown in Fig. 4B, the second member 50B has two elastic members 50BF, 50BS that form part of the shroud wall 31. Each of the elastic members 50BF, 50BS has an end surface 50BE facing the flow path FP. The two elastic members 50BF, 50BS are elastically deformable so that the distance between the two end surfaces 50BE changes. Note that the elastic members 50BF, 50BS may be separate from the shroud wall 31. Reference numeral 26P denotes the position of the impeller inlet 26.

[0095] Like the second member 50, the second member 50B has an upstream surface 50U and a downstream surface 50L. That is, each of the elastic members 50BF and 50BS has an upstream surface 50U and a downstream surface 50L. In each of the elastic members 50BF and 50BS, the upstream surface 50U, the end surface 50BE, and the downstream surface 50L are connected in order along the first direction FD. The second member 50B is configured to deform the elastic members 50BF and 50BS to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L, of the fluid FL flowing along the shroud wall 31 toward the impeller 21, compared to the flow rate of the fluid FL flowing toward the upstream surface 50U. In other words, the second member 50B is configured to reduce the flow rate QL of the fluid FL flowing through the region LP more than the flow rate QU of the fluid FL flowing through the region UP (QU>QL). That is, it is configured to reduce the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set so as to obtain the above-mentioned effect of refluxing the fluid FL.

[0096] Specifically, the flow rate of the fluid FL that collides with the upstream surface 50U increases as a result of the elastic members 50BF, 50BS deforming so as to protrude from the shroud wall 31. This makes it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L more than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0097] In other words, the second member 50B is configured to adjust the flow area 51 by deforming each of the elastic members 50BF, 50BS. The second member 50B configured in this manner can adjust the flow of the fluid FL along the shroud wall 31 toward the impeller 21 in the first direction FD, similar to the above-described second member 50. Therefore, by adjusting the amount of deformation of the two elastic members 50BF, 50BS, i.e., the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation occurring in the fluid FL.

[0098] <Third Modification of the Second Member> As shown in Figure 4C, the second member 50C has an upstream protrusion 50CU and a downstream protrusion 50CL. The upstream protrusion 50CU is arranged on the inner wall WL of the flow path FP on the upstream side US in the first direction FD. The downstream protrusion 50CL is arranged on the inner wall WL of the flow path FP on the downstream side DS of the upstream protrusion 50CU in the first direction FD. The upstream protrusion 50CU and the downstream protrusion 50CL are rotatable relative to each other in the circumferential direction CD of the flow path FP at the cross section of the flow path FP. Reference numeral 26P denotes the position of the impeller inlet 26.

[0099] Here, a specific description will be given with reference to Figures 4D and 4E. As shown in Figure 4D, the upstream protrusion 50CU is rotatable in a clockwise direction CW or a counterclockwise direction CCW when positioned on the inner wall WL of the flow path FP, as viewed in the first direction FD. Meanwhile, as shown in Figure 4E, the downstream protrusion 50CL is fixed to the inner wall WL of the flow path FP. This allows the upstream protrusion 50CU and the downstream protrusion 50CL to rotate relative to each other. The downstream protrusion 50CL may also be rotatable in a clockwise direction CW or a counterclockwise direction CCW. In this case, the upstream protrusion 50CU is fixed to the inner wall WL of the flow path FP. Furthermore, each of the upstream protrusion 50CU and the downstream protrusion 50CL may be rotatable. As shown in Figures 4D and 4E, a gap 50S is formed between the two upstream protrusions 50CU in the circumferential direction CD. The downstream protrusion 50CL is arranged to overlap the gap 50S or the upstream protrusion 50CU when viewed in the first direction FD. The area of ​​the gap 50S covered by the downstream protrusion 50CL is adjusted by relative rotation of the upstream protrusion 50CU and the downstream protrusion 50CL.

[0100] Like the second member 50, the second member 50C has an upstream surface 50U and a downstream surface 50L. The upstream surface 50U corresponds to the surface of the upstream protrusion 50CU with which the fluid FL flowing in the first direction FD collides, and the downstream surface 50CL with which the fluid FL flowing in the first direction FD collides and is located in the gap 50S. The downstream surface 50L corresponds to the downstream surface of the downstream protrusion 50CL.

[0101] The second member 50C is configured to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L by the relative rotation of the upstream protrusions 50CU and the downstream protrusions 50CL, among the fluid FL flowing along the shroud wall 31 toward the impeller 21, by less than the flow rate of the fluid FL flowing toward the upstream surface 50U. In other words, the second member 50C is configured to reduce the flow rate QL of the fluid FL flowing through the region LP by less than the flow rate QU of the fluid FL flowing through the region UP (QU > QL). That is, the second member 50C is configured to reduce the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set to obtain the above-mentioned effect of reflux of the fluid FL.

[0102] Specifically, the flow rate of the fluid FL that collides with the upstream surface 50U increases as a result of the upstream protrusion 50CU and the downstream protrusion 50CL rotating relative to each other, which makes it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L to be lower than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0103] In other words, the flow area 51 is adjusted by adjusting the gap area of ​​the gap 50S formed by the overlap of the upstream protrusion 50CU and the downstream protrusion 50CL as viewed in the first direction FD in accordance with the relative rotation of the upstream protrusion 50CU and the downstream protrusion 50CL. The second member 50C configured in this manner, like the second member 50 described above, can adjust the flow of the fluid FL along the shroud wall 31 toward the impeller 21 in the first direction FD. Therefore, by adjusting the amount of relative rotation of the upstream protrusion 50CU with respect to the downstream protrusion 50CL, i.e., the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation occurring in the fluid FL.

[0104] <Fourth Modification of the Second Member> As shown in FIG. 4F, the second member 50D has a shaft portion 50DA extending in a direction XD. Here, the direction XD is a direction intersecting the radial direction RD of the flow path FP in the cross section of the flow path FP and also intersecting the first direction FD. The second member 50D, which is a plate member, is supported by the shaft portion 50DA so as to be rotatable around the shaft portion 50DA. The second member 50D is configured to adjust the flow area 51 by rotating around the shaft portion 50DA. Reference numeral 26P denotes the position of the impeller inlet 26.

[0105] Like the second member 50, the second member 50D has an upstream surface 50U and a downstream surface 50L. Rotation of the second member 50D around the shaft portion 50DA reduces the flow rate of the fluid FL flowing downstream of the downstream surface 50L relative to the flow rate of the fluid FL flowing along the shroud wall 31 toward the impeller 21. In other words, the second member 50D reduces the flow rate QL of the fluid FL flowing through the region LP relative to the flow rate QU of the fluid FL flowing through the region UP (QU > QL). That is, the second member 50D reduces the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set to achieve the aforementioned effect of refluxing the fluid FL.

[0106] Specifically, the rotation of the second member 50D around the shaft portion 50DA increases the flow rate of the fluid FL that collides with the upstream surface 50U, which makes it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L to be lower than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0107] The second member 50D configured in this manner, like the second member 50 described above, can adjust the flow of the fluid FL along the shroud wall 31 in the first direction FD toward the impeller 21. Therefore, by adjusting the amount of rotation of the second member 50D around the shaft portion 50DA, i.e., the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation occurring in the fluid FL.

[0108] <Fifth Modification of the Second Member> While two shaft portions 50DA are shown in FIG. 4F above, the number of shaft portions 50DA may be three or more. As shown in FIG. 4G , the second member 50E has a structure in which six shaft portions 50DA are arranged along the inner wall WL of the flow path FP. A plate member 50EF is provided on each of the six shaft portions 50DA. The plate member 50EF is rotatably supported around the shaft portion 50DA by the shaft portion 50DA. The plate member 50EF has an upstream surface 50U and a downstream surface 50L. By rotating the plate member 50EF around the shaft portion 50DA, the flow rate of the fluid FL flowing downstream of the downstream surface 50L is reduced compared to the flow rate of the fluid FL flowing along the shroud wall 31 toward the impeller 21. In other words, the plate member 50EF is configured to reduce the flow rate QL of the fluid FL flowing through the region LP more than the flow rate QU of the fluid FL flowing through the region UP (QU>QL). That is, the plate member 50EF is configured to reduce the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set to obtain the above-mentioned effect of refluxing the fluid FL.

[0109] Specifically, the rotation of the plate member 50EF around the shaft portion 50DA increases the flow rate of the fluid FL that collides with the upstream surface 50U, thereby making it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L more than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0110] In other words, the plate member 50EF is configured to rotate around each of the six shaft portions 50DA to adjust the flow area 51. By adjusting the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation that occurs in the fluid FL.

[0111] <Sixth Modification of the Second Member> As shown in Figure 4H, the second member 50F has a shaft portion 50FA extending in the radial direction RD of the flow path FP in the cross section of the flow path FP. The second member 50F, which is a plate member, is supported by the shaft portion 50FA so as to be rotatable around the shaft portion 50FA. The shaft portion 50FA is provided at the downstream end of the second member 50F in the first direction FD. Reference numeral 26P indicates the position of the impeller inlet 26. Even when the second member 50F rotates around the shaft portion 50FA, the second member 50F is not positioned downstream of the position indicated by reference numeral 26P.

[0112] Like the second member 50, the second member 50F has an upstream surface 50U and a downstream surface 50L. Rotation of the second member 50F around the shaft portion 50FA reduces the flow rate of the fluid FL flowing downstream of the downstream surface 50L relative to the flow rate of the fluid FL flowing along the shroud wall 31 toward the impeller 21. In other words, the second member 50F reduces the flow rate QL of the fluid FL flowing through the region LP relative to the flow rate QU of the fluid FL flowing through the region UP (QU > QL). That is, the second member 50F reduces the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set to achieve the aforementioned reflux effect of the fluid FL.

[0113] Specifically, the rotation of the second member 50F around the shaft portion 50FA increases the flow rate of the fluid FL that collides with the upstream surface 50U, which makes it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L to be lower than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0114] The second member 50F configured in this manner is configured to rotate around the shaft portion 50FA to adjust the flow area 51. Therefore, by adjusting the amount of rotation of the second member 50F around the shaft portion 50FA, i.e., the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation occurring in the fluid FL.

[0115] <Seventh Modification of the Second Member> While two shaft portions 50FA are shown in FIG. 4H above, the number of shaft portions 50FA may be three or more. As shown in FIG. 4I , the second member 50G has a structure in which six plate members 50FF are arranged along the inner wall WL of the flow path FP. Each of the six plate members 50FF is supported by a shaft portion 50FA so as to be rotatable around the shaft portion 50FA. The plate members 50FF have an upstream surface 50U and a downstream surface 50L. By rotating the plate members 50FF around the shaft portions 50FA, the flow rate of the fluid FL flowing downstream of the downstream surface 50L is reduced compared to the flow rate of the fluid FL flowing toward the upstream surface 50U along the shroud wall 31 toward the impeller 21. In other words, the plate member 50FF is configured to reduce the flow rate QL of the fluid FL flowing through the region LP more than the flow rate QU of the fluid FL flowing through the region UP (QU>QL). That is, the plate member 50FF is configured to reduce the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set to obtain the above-mentioned effect of refluxing the fluid FL.

[0116] Specifically, the rotation of the plate member 50FF around the shaft portion 50FA increases the flow rate of the fluid FL that collides with the upstream surface 50U, thereby making it possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L more than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0117] In other words, the plate member 50FF is configured to rotate around each of the six shaft portions 50FA to adjust the flow area 51. By adjusting the flow area 51 of the fluid FL, it is possible to adjust the degree of stagnation that occurs in the fluid FL.

[0118] <Eighth Modification of the Second Member> As shown in FIG. 4J , the second member 50H is capable of adjusting the distance DT between the second member 50H and the impeller inlet 26 in the first direction FD. In FIG. 4J , reference symbol 26P indicates the position of the impeller inlet 26. Reference symbol P1 indicates the position of the second member 50H at which the second member 50H is closest to the impeller inlet 26. At position P1, the distance between the second member 50H and the impeller inlet 26 is DT1. Reference symbol P2 indicates the position of the second member 50H at which the second member 50H is farthest from the impeller inlet 26. At position P2, the distance between the second member 50H and the impeller inlet 26 is DT2. The distance DT2 is greater than the distance DT1.

[0119] Like the second member 50, the second member 50H has an upstream surface 50U and a downstream surface 50L. The second member 50H can be positioned between positions P1 and P2. When the second member 50H is positioned at position P1, the second member 50H can be positioned closer to the impeller inlet 26. This reduces the flow rate of the fluid FL flowing downstream of the downstream surface 50L relative to the flow rate of the fluid FL flowing along the shroud wall 31 toward the impeller 21. In other words, the second member 50H reduces the flow rate QL of the fluid FL flowing through the region LP less than the flow rate QU of the fluid FL flowing through the region UP (QU > QL). In other words, the second member 50H reduces the flow rate QL of the fluid FL in the region LP between the downstream surface 50L and the impeller inlet 26. The distance between the downstream surface 50L and the position 26P, i.e., the width of the region LP in the first direction FD, is appropriately set so as to obtain the above-mentioned effect of reflux of the fluid FL.

[0120] Specifically, by bringing the second member 50H closer to the impeller inlet 26, it is possible to reduce the flow rate of the fluid FL flowing downstream of the downstream surface 50L more than the flow rate of the fluid FL flowing toward the upstream surface 50U.

[0121] In other words, the flow of the fluid FL changes depending on the position of the second member 50H. By moving the second member 50H between positions P1 and P2, it is possible to adjust the degree of stagnation that occurs in the fluid FL.

[0122] 1 , the fluid machine 10 has two drive units, a first drive unit D1 and a second drive unit D2. The fluid machine 10 may move the first member 40 and the second member 50 using a single drive unit. That is, the single drive unit is connected to the first member 40 and the second member 50 and is configured to move the first member 40 relative to the shroud wall 31 and to move the second member 50 relative to the shroud wall 31. In this configuration, the single drive unit may move the first member 40 and the second member 50 so that the first member 40 and the second member 50 are synchronized with each other.

[0123] Second Embodiment Fluid Machine In the above-described embodiment, the fluid machine 10 has been described as including a first member 40 capable of adjusting the amount of protrusion AP relative to the flow path FP, and a second member 50 capable of adjusting the flow of the fluid FL along the shroud wall 31. In the second embodiment described below, a case will be described in which the fluid machine drives only the first member without using the second member 50. Here, the same members as those described with reference to FIGS. 1 to 2B are denoted by the same reference numerals, and their description will be omitted or simplified. Also, a drive unit that moves the first member relative to the shroud wall 31 is not shown.

[0124] Similar to the first embodiment, the fluid machine according to the second embodiment includes a rotating structure 20, a casing 30, a flow path FP, and a first drive unit D1. Furthermore, the fluid machine according to the second embodiment includes a first member 60A instead of the first member 40 according to the first embodiment.

[0125] <First Member> The first member 60A has a configuration generally similar to that of the first member 40. However, the first member 60A has a protrusion, which differs from the first member 40. As shown in FIG. 5A , the first member 60A has a protrusion 61 and a base 62. The base 62 extends in the extension direction of the first member 60A. In this embodiment, the extension direction of the first member 60A corresponds to the axial direction AD. Note that the extension direction of the first member 60A may be a direction inclined with respect to the axial direction AD.

[0126] The protrusion 61 is provided on the base 62 so as to protrude toward the upstream side in the first direction FD. The protrusion 61 has a first extension 63 that faces the main plate side wall 32. The first extension 63 is provided on a part of the base 62 and extends from the base 62 toward the impeller 21. The first extension 63 extends in a direction parallel to the first direction FD. The first extension 63 has a tip 60X that is located at the tip end of the first member 60A. The tip 60X is a portion that corresponds to the tip 41 described above.

[0127] The first member 60A has a second extension portion 64 facing the first extension portion 63. The base 62 has an accommodation region 65 that is accommodated in the shroud wall 31. The second extension portion 64 is provided in the accommodation region 65 of the base 62. The first member accommodating groove 35 provided in the shroud wall 31 has a width that corresponds to the length of the second extension portion 64 in the first direction FD. This allows the first member accommodating groove 35 to accommodate the second extension portion 64 as the protrusion amount AP is adjusted.

[0128] <Operation and Effect> Next, the operation and effect of the fluid machine according to the second embodiment will be described. In the fluid machine according to the second embodiment, the rotation of the rotating structure 20 causes the plurality of blades 25 to push out the fluid FL, and the fluid FL flows through the flow path FP from the inlet 33 to the outlet 34 of the casing 30. In this state, the first member 60A moves, and as described with reference to Figures 2A and 2B, the protrusion amount AP of the first member 60A with respect to the flow path FP is adjusted.

[0129] As shown in FIGS. 2A and 2B , adjusting the protrusion amount AP allows the tip 60X of the first member 60A to move from the minimum position P0 to the intermediate position PM, and also allows the tip 60X of the first member 60A to move from the minimum position P0 to the maximum position PX. In this case, the fluid FL flowing in the first direction FD in the second region R2 collides with the first member 60A. The fluid FL that collides with the first member 60A flows in the second direction SD in the third region R3. A reflux of the fluid FL occurs in the second region R2 and the third region R3. This reduces the flow rate of the fluid machine. In particular, because the first member 60A has a base 62, a first extension 63, and a second extension 64, the fluid FL flows into the region surrounded by the base 62, the first extension 63, and the second extension 64, promoting the reflux of the fluid FL.

[0130] Furthermore, by adjusting the protrusion amount AP, the tip end 60X of the first member 60A can be moved from the intermediate position PM to the minimum position P0, and the tip end 60X of the first member 60A can be moved from the maximum position PX to the minimum position P0. In this case, the compressed state of the fluid FL by the first member 60A is suddenly released, the reflux of the fluid FL in the second region R2 and the third region R3 quickly disappears, the flow rate of the refluxing fluid FL is quickly discharged from the outlet 34, and new fluid FL is quickly sucked in from the inlet 33. In other words, the flow rate of the fluid FL can be quickly increased.

[0131] <Modifications of the First Member> Next, modifications of the first member will be described with reference to Figures 5B to 5J. Here, the same members as those described with reference to Figures 1 to 2B and 5A are given the same reference numerals, and their description will be omitted or simplified.

[0132] <First Modification of First Member> The first member 60B shown in FIG. 5B differs from the first member 60A in that it does not include the second extension portion 64. That is, the first member 60B includes a first extension portion 63 and a base portion 62. In the example shown in FIG. 5B , the casing 30 includes a housing portion 37 provided in the shroud wall 31. The housing portion 37 has a shape corresponding to the first extension portion 63. When the tip portion 60X is positioned at the minimum position P0, the housing portion 37 is configured to house the first extension portion 63. In this configuration, the protrusion amount AP of the first member 60B relative to the flow path FP is adjusted. The first member 60B can achieve the same or similar effects as the first member 60A.

[0133] <Second Modification of First Member> The first member 60C shown in FIG. 5C extends in a direction inclined in the first direction FD, which differs from the first member 60B. The first extending portion 63 of the protrusion 61 protrudes toward the upstream side in the first direction FD. Even in this configuration, the protrusion amount AP of the first member 60C relative to the flow path FP can be adjusted. The first member 60C can achieve the same or similar effects as the first member 60A.

[0134] <Third Modification of First Member> The structure of the base 62 of the first member 60D shown in FIG. 5D differs from that of the first member 60A. The base 62 includes a first base 62F and a second base 62S. The first base 62F is positioned in the first member accommodating groove 35 even when the tip 60X is positioned at the minimum position P0, the intermediate position PM, or the maximum position PX. The second base 62S is located between the first base 62F and the first extending portion 63. The second base 62S has an inclined surface facing upstream in the first direction FD. The first extending portion 63 is connected to the inclined surface of the second base 62S. Even with this configuration, the protrusion amount AP of the first member 60D relative to the flow path FP can be adjusted. The first member 60D can achieve the same or similar effects as the first member 60A.

[0135] <Fourth Modification of First Member> The structure of the protrusion 61 and base 62 of the first member 60E shown in FIG. 5E differs from that of the first member 60A. The first member 60E has a base 62, similar to the first member 60A. The base 62 has a base upstream surface 62U facing the impeller 21. The protrusion 61 has a recess 62R provided in the base upstream surface 62U. The recess 62R has a bottom 62B and two inclined surfaces 62K sandwiching the bottom 62B. The bottom 62B is the portion of the recess 62R that is furthest from the base upstream surface 62U in the first direction FD. In terms of cross-sectional shape, the bottom 62B and the two inclined surfaces 62K form corners. The inclined surfaces 62K correspond to the protrusion 61. In other words, the protrusion 61 is formed around the bottom 62B. In other words, the protrusion 61 forms a part of the recess 62R.

[0136] The first member 60E having such a recessed portion 62R can also adjust the protrusion amount AP, achieving the same effect as the first member 60A. Specifically, as shown in FIGS. 2A and 2B , adjusting the protrusion amount AP allows the tip end 60X of the first member 60E to move from the minimum position P0 to the intermediate position PM, and also allows the tip end 60X of the first member 60E to move from the minimum position P0 to the maximum position PX. In this case, the fluid FL flowing in the first direction FD in the second region R2 collides with the first member 60E and flows in the second direction SD, causing a reflux of the fluid FL in the second region R2 and the third region R3. This reduces the flow rate of the fluid machine. In particular, because the first member 60E has the recessed portion 62R provided in the base 62, the fluid FL flowing into the recessed portion 62R promotes reflux of the fluid FL.

[0137] Furthermore, by adjusting the protrusion amount AP, the tip end 60X of the first member 60E can be moved from the intermediate position PM to the minimum position P0, and the tip end 60X of the first member 60E can be moved from the maximum position PX to the minimum position P0. In this case, the compression state of the fluid FL by the first member 60E is suddenly released, and the reflux of the fluid FL in the second region R2 and the third region R3 quickly disappears. In other words, the flow rate of the fluid FL can be quickly increased.

[0138] <Fifth Modification of First Member> The cross-sectional shape of the recessed portion 62R of the first member 60F shown in FIG. 5F is different from that of the first member 60E. Specifically, the recessed portion 62R has a bottom 62B and a curved surface 62C located around the bottom 62B. With respect to the cross-sectional shape, the bottom 62B and the curved surface 62C form a curved portion. The curved surface 62C corresponds to the protruding portion 61. In other words, the protruding portion 61 is formed around the bottom 62B. In other words, the protruding portion 61 forms a part of the recessed portion 62R. Even with this configuration, the protrusion amount AP of the first member 60C relative to the flow path FP can be adjusted. The first member 60F can also achieve the same or similar effects as the first member 60E.

[0139] <Sixth Modification of First Member> The size of the recessed portion 62R of each of the first member 60G shown in FIG. 5G and the first member 60H shown in FIG. 5H is different from that of the first member 60F. The depth DP of the recessed portion 62R of the first member 60G is greater in the first direction FD than the depth of the recessed portion 62R of the first member 60F. The width WD of the recessed portion 62R of the first member 60H is greater in the radial direction RD than the width of the recessed portion 62R of the first member 60F. As shown in each of the first members 60G and 60H, the depth DP and width WD of the recessed portion 62R can be freely changed. Even with this configuration, the same or similar effects as those of the first member 60E can be obtained.

[0140] <Seventh Modification of First Member> A first member 60I shown in Fig. 5I differs from first member 60F in that a through hole is provided in the base 62. In first member 60I shown in Fig. 5I, protrusion 61 and recess 62R are omitted. The seventh modification described below can be applied to a first member having protrusion 61 or recess 62R.

[0141] In the first member 60I, the base 62 has a base upstream surface 62U that faces the impeller 21 and a base downstream surface 62D that is opposite the base upstream surface 62U. Furthermore, the base 62 has a through hole 62P that is provided in the base 62 and extends from the base upstream surface 62U toward the base downstream surface 62D. In other words, the through hole 62P has an opening that opens to the base upstream surface 62U and an opening that opens to the base downstream surface 62D. Note that although only one through hole 62P is shown in the first member 60I shown in FIG. 5I, a plurality of through holes 62P are provided throughout the entire first member 60I.

[0142] <Operation and Effect> Next, the operation and effect of the fluid machine including the first member 60I will be described. In the fluid machine, the rotation of the rotating structure 20 causes the plurality of blade plates 25 to push out the fluid FL, and the fluid FL flows through the flow path FP from the inlet 33 toward the outlet 34 of the casing 30. In this state, the first member 60I having the through hole 62P moves, and as described with reference to Figures 2A and 2B, the protrusion amount AP of the first member 60I with respect to the flow path FP is adjusted.

[0143] 2A and 2B , by adjusting the protrusion amount AP, the tip end 60X of the first member 60I can be moved from the minimum position P0 to the intermediate position PM, and the tip end 60X of the first member 60I can be moved from the minimum position P0 to the maximum position PX. In this case, the fluid FL flowing in the first direction FD in the second region R2 collides with the first member 60I and flows in the second direction SD, causing a reflux of the fluid FL in the second region R2 and the third region R3. This reduces the flow rate of the fluid machine.

[0144] Here, the base downstream surface 62D is located further outward in the radial direction RD than the base upstream surface 62U. Therefore, due to the law of conservation of angular momentum, the velocity of the fluid FL flowing in the first direction FD without colliding with the first member 60I decreases toward the outside in the radial direction RD. Furthermore, the pressure of the fluid FL flowing in the first direction FD without colliding with the first member 60I increases toward the outside in the radial direction RD. The base downstream surface 62D is located further outward in the radial direction RD than the base upstream surface 62U. Therefore, the pressure at the base downstream surface 62D is higher than the pressure at the base upstream surface 62U.

[0145] Because the first member 60I has through holes 62P, a portion of the fluid FL flowing through the flow path FP flows through the through holes 62P in the second direction SD. The fluid FL that flows through the through holes 62P reaches the base upstream surface 62U and merges with the fluid FL flowing in the second region R2. That is, the fluid FL that flows through the through holes 62P in the second direction SD merges with the fluid FL flowing in the second region R2 in the first direction FD. This results in a merged fluid at the base upstream surface 62U. The merged fluid accelerates the flow of the fluid FL in the third region R3. Therefore, by using the first member 60I having the through holes 62P, a merged fluid is generated, which can promote the occurrence of reflux of the fluid FL in the second region R2 and the third region R3.

[0146] <Eighth Modification of First Member> The through holes 62P provided in the base 62 of the first member 60J shown in FIG. 5J are inclined with respect to the radial direction RD, which is different from the first member 60I. As shown in FIG. 5J, the base 62 is provided with a plurality of through holes 62P in the circumferential direction CD. The plurality of through holes 62P are provided, for example, at equal intervals in the circumferential direction CD. Each of the plurality of through holes 62P extends so as to be inclined with respect to the radial direction RD. Even with this configuration, the same or similar effects as those of the first member 60I can be obtained.

[0147] <Modifications of the Second Embodiment> In the above-described second embodiment and modifications of the first members, the first members 60A to 60J are applied to the fluid machine according to the second embodiment. The first members 60A to 60J can also be applied to the fluid machine 10 according to the first embodiment. In this case, one of the first members 60A to 60J can cooperate with the second member 50. Furthermore, one of the first members 60A to 60J can cooperate with one of the second members 50A to 50G described in the modifications of the first embodiment.

[0148] <Third embodiment> <Blade> Next, a blade 25 according to a third embodiment will be described. In the following description, one of the plurality of blades 25 will be described. Here, the same members as those described with reference to Figures 1 to 2B are given the same reference numerals, and their description will be omitted or simplified. In Figures 6A and 6B, components other than the impeller and blades among those constituting the fluid machine are omitted.

[0149] 6A shows a typical blade plate 125, a typical blade main plate 124, and a typical impeller outlet 127. Also shown in FIG. 6A is a velocity triangle that is a velocity vector at the tip of the blade plate 125 located at the impeller outlet 127. ２ means the relative velocity of the fluid with respect to the impeller. ２ means the peripheral speed of the blade main plate 124. ２ is the relative velocity W ２ and peripheral speed U ２ The vector sum is the absolute velocity of the outflowing fluid FL. An explanation with reference to the velocity triangle will be given later.

[0150] As shown in FIG. 6A , the blade plate 125 extends from the center of the main blade plate 124 toward the impeller outlet 127. Here, the angle of the blade plate 125 at the impeller outlet 127 with respect to the axis AX parallel to the radial direction RD is defined as B. In other words, the blade plate 125 at the impeller outlet 127 is inclined at angle B toward the axis AX parallel to the radial direction RD. Regarding the positive and negative values ​​of angle B, when the axis AX is used as the reference, the angle B in the rotation direction +R of the impeller 21 is defined as a positive value (+B), whereas the angle B in the reverse direction −R opposite to the rotation direction +R is defined as a negative value (−B). When the angle of the blade plate 125 is defined in this way, the angle of the blade plate 125 in the impellers of general compressors and pumps is a negative value or zero. In particular, the angle of the blade plate 125 at the impeller inlet 26 is a negative value. The reason for this is as follows: The flow of fluid flowing into the impeller is usually parallel to the axial direction AD and does not have a component in the circumferential direction CD. Therefore, a fluid having a relative velocity in the opposite direction to the circumferential direction CD flows into the blade plate 125, which is rotating (clockwise in FIG. 6A , rotation direction +R) and has a velocity in the circumferential direction CD. In order for such a fluid to flow into the blade plate 125 without collision, the inlet of the blade plate 125 needs to be inclined in the circumferential direction CD.

[0151] Next, this embodiment will be described with reference to FIG. 6B . As shown in FIG. 6B , the flow path FP between the impeller 21 and the shroud wall 31 is divided into the first region R1, the second region R2, and the third region R3, as described above, depending on the protrusion amount AP of the first member. Therefore, the first region R1, the second region R2, and the third region R3 are also formed in the blade plate 25. In other words, the first region R1, the second region R2, and the third region R3 are formed in the blade plate 25 depending on the height Z of the blade plate 25 in the axial direction AD. Note that in FIG. 6B , symbol Z0 indicates the case where the height of the blade plate 25 is zero and indicates the position of the surface of the main blade plate 24. As the height of the blade plate 25 increases from position Z0, the first region R1, the second region R2, and the third region R3 are formed in the blade plate 25, in this order.

[0152] In the graph shown in FIG. 6C , B represents the angle of the blade plate 25 near the impeller outlet 27 described in FIG. 6A , and Z represents the height of the blade plate 25 in the axial direction AD described in FIG. 6B . The solid line indicated by the symbol SL1 shows an example of the shape of the blade plate 25. As shown by the solid line SL1, when the height of the blade plate 25 is significantly lower than position Z1, the angle B of the blade plate 25 is negative. As the height of the blade plate 25 increases, the value of the angle B of the blade plate 25 increases, and the value of the angle B changes from a negative value to a positive value. Furthermore, as the height of the blade plate 25 increases, the value of the angle B of the blade plate 25 increases, and when the height of the blade plate 25 reaches position Z1, the value of the angle B becomes the highest positive value. Here, position Z1 corresponds to the second region R2 of the blade plate 25 shown in FIG. 6B . Next, as the height of the blade plate 25 increases, the value of angle B of the blade plate 25 begins to decrease, and the value of angle B changes from a positive value to a negative value. Furthermore, as the height of the blade plate 25 increases, the value of angle B of the blade plate 25 decreases, and when the height of the blade plate 25 reaches position Z2, the value of angle B becomes negative. Here, position Z2 corresponds to the third region R3 of the blade plate 25 shown in FIG. 6B .

[0153] In this embodiment, the value of angle B is a positive value when the height of the slat 25 is at position Z1, but the value of angle B may be 0 degrees. Also, the value of angle B is a negative value when the height of the slat 25 is at position Z2, but the value of angle B may be 0 degrees. The distribution of angles between points is also not limited to the above-described embodiment.

[0154] That is, with regard to the angle B of the blade plate 25 in the second region R2 near the impeller outlet 27, when the angle B of the blade plate 25 is set to 0 degrees with respect to the radial direction RD of the impeller 21 and is set to a positive value with respect to the rotation direction +R of the impeller 21, the maximum value of the angle B of the blade plate 25 is 0 degrees or a positive value. In particular, the above condition regarding the angle B of the blade plate 25 is more preferable when the tip end 41 of the first member 40 is positioned at the maximum position PX.

[0155] Furthermore, with regard to the angle B of the blade plate 25 in the third region R3 at the impeller outlet 27, when the angle B of the blade plate 25 is set to 0 degrees with respect to the radial direction RD of the impeller 21 and is set to a positive value with respect to the rotation direction +R of the impeller 21, the minimum value of the angle B of the blade plate 25 is 0 degrees or a negative value. In particular, the above condition regarding the angle B of the blade plate 25 is more preferable when the tip end 41 of the first member 40 is positioned at the maximum position PX.

[0156] 7A to 7D, the effects of the present embodiment will be described. The velocity triangles shown in Figures 7A to 7D show the relationship between the velocity of the fluid FL and the velocity (circumferential velocity) of the outer periphery of the impeller 21 when the fluid FL flows out of the second region R2 of the impeller 21, collides with the first member 40, and flows into the third region R3 of the impeller 21 in a case where the first member 40 protrudes from the shroud wall 31 in a fluid machine.

[0157] 7A shows a velocity triangle when the fluid FL flows out from the second region R2 of the impeller outlet 27 in the impeller 21 according to this embodiment. ２ is the speed (circumferential speed) in the rotation direction at the impeller outlet 27. ２ is the velocity at which the fluid FL flows out of the impeller 21, and is the relative velocity of the fluid FL with respect to the impeller 21. In the impeller 21 according to this embodiment, the maximum value of the angle B in the second region R2 of the blade plate 25 in the vicinity of the impeller outlet 27 is a positive value. Therefore, the relative velocity W ２ has a vector pointing in a direction in which the angle B is a positive value. ２ is the relative velocity W ２ and peripheral speed U ２ and is the vector sum of the absolute velocity of the fluid FL flowing out of the impeller 21.

[0158] 7B shows a velocity triangle when the fluid FL flowing out from the second region R2 of the impeller outlet 27 according to this embodiment collides with the first member 40, the component of the velocity of the fluid FL directed in the radial direction RD is reversed, and the fluid FL flows into the third region R3 of the impeller outlet 27. ２ＲＥis the absolute velocity of the fluid FL that collides with the first member 40 and reverses direction. Here, it is assumed that there is no loss of the fluid FL from when it leaves the second region R2 of the impeller 21 until it flows into the third region R3. The fluid FL flows at the same peripheral velocity U as when it flows out from the impeller outlet 27. ２ The fluid FL flows into the third region R3 at the outlet 27 of the impeller 21, which rotates at a relative velocity W ２ＲＥ is calculated by vector calculation as absolute velocity C ２ＲＥ From peripheral speed U ２ This gives the relative velocity W ２ＲＥ is obtained.

[0159] In the fluid machine according to this embodiment, the minimum value of the blade angle in the third region R3 near the impeller outlet 27 is a negative value. Therefore, the fluid FL flows into the third region R3 so that the blade angle of the blade plate 25 in the third region R3 near the impeller outlet 27 follows the relative velocity of the inflowing fluid FL. Therefore, it is possible to minimize loss when the fluid FL flows into the third region R3 at the impeller outlet 27, and it is possible to minimize loss due to reflux in the third region R3 and the second region R2.

[0160] Therefore, even when the suction flow rate of the fluid machinery is reduced or adjusted by the first member 40 protruding from the shroud wall 31, a decrease in efficiency can be minimized. Here, the suction flow rate is equal to the discharge flow rate. Furthermore, the minimum value of the angle of the blade 25 in the third region R3 near the impeller outlet 27 is a negative value. Therefore, as explained above, as compared with the case where the angle of the blade 25 is a positive value, the difference between the angle of the blade 25 at the impeller inlet 26, where the angle of the blade 25 is a negative value, is small. Therefore, bending of the blade 25 in the third region R3 can be suppressed.

[0161] The third region R3 is located near the shroud wall 31. Therefore, the distance of the blade 25 in the meridian plane is shorter than those of the first region R1 and the second region R2. If the angle of the blade 25 changes significantly over a short section, the blade 25 bends more. If the bending of the blade 25 becomes greater, so-called separation occurs, in which the flow of the fluid FL does not flow along the blade 25, and the efficiency of the impeller 21 decreases. In the impeller 21 according to this embodiment, the minimum value of the angle of the blade 25 in the third region R3 near the impeller outlet 27 is a negative value. Therefore, the efficiency of the impeller 21 does not decrease.

[0162] 7C shows a velocity triangle when the fluid FL flows out from the second region R2 of the impeller outlet 27 of the impeller 21 according to this embodiment when the angle of the blade plate 25 in the second region R2 near the impeller outlet 27 is 0. The velocity symbols have the same meanings as those described above. The fluid FL that flows out from the second region R2 of the impeller outlet 27 flows out at an angle of 0 along the blade plate 25 facing the radial direction RD. As a result, the absolute velocity C shown in FIG. 7C ２ is obtained.

[0163] 7D shows a velocity triangle when the angle of the blade plate 25 in the third region R3 near the impeller outlet 27 of the impeller 21 according to this embodiment is 0, the fluid FL flowing out from the second region R2 of the impeller outlet 27 collides with the first member 40, the outward component of the velocity of the fluid FL in the radial direction RD reverses, and the fluid FL flows into the third region R3 of the impeller outlet 27. The fluid FL that collides with the first member 40 and reverses its direction moves at an absolute velocity C ２ＲＥ And the peripheral speed U ２The fluid FL that flows into the third region R3 of the impeller outlet 27 rotating at 100° flows in at a relative velocity inward in the radial direction RD. In the fluid machine according to this embodiment, the minimum value of the blade angle in the third region R3 near the impeller outlet 27 is 0. Therefore, the fluid FL flows into the third region R3 so that the blade angle of the blade plate 25 in the third region R3 near the impeller outlet 27 matches the relative velocity of the inflowing fluid FL. This minimizes loss of the fluid FL when it flows into the third region R3 of the impeller outlet 27, and minimizes loss due to reflux in the third region R3 and the second region R2.

[0164] Therefore, even when the suction flow rate of the fluid machinery is reduced or adjusted by the first member 40 protruding from the shroud wall 31, a decrease in efficiency can be minimized. Here, the suction flow rate is equal to the discharge flow rate. Furthermore, the minimum value of the angle of the blade 25 in the third region R3 near the impeller outlet 27 is 0. Therefore, as explained above, as compared with the case where the angle of the blade 25 is a positive value, the difference between the angle of the blade 25 at the impeller inlet 26, where the angle of the blade 25 is a negative value, is small. Therefore, bending of the blade 25 in the third region R3 can be suppressed.

[0165] The third region R3 is located near the shroud wall 31. Therefore, the distance of the blade 25 in the meridian plane is shorter than those of the first region R1 and the second region R2. If the angle of the blade 25 changes significantly over a short section, the blade 25 will bend more significantly. If the blade 25 bends more significantly, so-called separation occurs, in which the flow of the fluid FL does not flow along the blade 25, and the efficiency of the impeller 21 decreases. In the impeller 21 according to this embodiment, the minimum value of the angle of the blade 25 in the third region R3 near the impeller outlet 27 is 0, and therefore the efficiency of the impeller 21 does not decrease.

[0166] As described above, by using the vane plate 25 according to the third embodiment, the effects achieved by the first embodiment can be further enhanced. That is, the occurrence of reflux of the fluid FL in the second region R2 and the third region R3 can be promoted while minimizing losses. Since the flow rate reduction in the fluid machine 10 can be promoted, a decrease in efficiency can be minimized while promoting a reduction or adjustment of the flow rate. The dotted lines DL1 and DL2 shown in FIG. 6C indicate modified shapes of the vane plate 25. The effects described above can also be achieved with each of the dotted lines DL1 and DL2. While the above description has been given of the case where the first member 40 is used, each of the first members 60A to 60J described above may be used instead of the first member 40.

[0167] <Fourth embodiment> <Impeller> Next, an impeller 21 according to a fourth embodiment will be described. Here, the same components as those described with reference to Figures 1 to 2B are given the same reference numerals, and their description will be omitted or simplified. In Figure 8A, components other than the impeller among the components that make up the fluid machine are omitted.

[0168] The impeller 21 has a partition member 28 facing the shroud wall 31. The partition member 28 has a blade opening 28P. The blade opening 28P is located closer to the impeller inlet 26 than to the impeller outlet 27. The partition member 28 is fixed to, for example, the blade plate 25. This maintains the gap between the blade main plate 24 and the partition member 28, and also maintains the gap between the shroud wall 31 and the partition member 28. In particular, the partition member 28 is located at the boundary between the second region R2 and the third region R3 between the blade main plate 24 and the shroud wall 31.

[0169] <Effects> Next, the effects of the impeller 21 including the partition member 28 will be described. As described above, by adjusting the protrusion amount AP, the fluid FL flows in the first direction FD in the second region R2. When the fluid FL flowing in the second region R2 collides with the first member, the fluid FL flows in the second direction SD in the third region R3. At this time, the partition member 28 separates the fluid FL flowing in the second region R2 from the fluid FL flowing in the third region R3. Furthermore, the fluid FL flowing in the third region R3 flows from the third region R3 into the second region R2 via the blade opening 28P. Therefore, the provision of the partition member 28 on the impeller 21 can promote the flow of the fluid FL flowing in the second region R2 and the flow of the fluid FL flowing in the third region R3. This promotes the return flow of the fluid FL in the second region R2 and the third region R3. This reduces the flow rate of the fluid machine.

[0170] <Modification of the Fourth Embodiment> Next, a modification of the first member will be described with reference to FIG. 8B . Here, the same components as those described with reference to FIG. 8A are denoted by the same reference numerals, and their description will be omitted or simplified. The impeller 21 shown in FIG. 8B differs from the structure shown in FIG. 8A in the position of the blade opening 28P. In the impeller 21 shown in FIG. 8B , the blade opening 28P is located closer to the impeller inlet 26 than the impeller outlet 27 and at the upstream end of the partition member 28. In other words, the blade opening 28P is located at the impeller inlet 26. Even with this configuration, the partition member 28 can promote the flow of the fluid FL flowing through the second region R2 and the third region R3. This promotes the return flow of the fluid FL in the second region R2 and the third region R3. This reduces the flow rate of the fluid machine.

[0171] 8B, the blade opening 28P is disposed upstream of the position of the blade opening 28P in FIG. 8A. Therefore, in the first direction FD, the length over which the fluid FL flows in the second region R2 can be increased, and the length over which the fluid FL flows in the third region R3 can be increased. In other words, by adjusting the position of the blade opening 28P, the degree of reflux of the fluid FL in the second region R2 and the third region R3 can be adjusted.

[0172] 1 to 2B are denoted by the same reference numerals, and the description thereof will be omitted or simplified. In Fig. 9, the components constituting the fluid machine other than the impeller are omitted.

[0173] The impeller 21A shown in Fig. 9 has a side plate 29. The side plate 29 is joined to the blade plate 25 so as to be spaced apart from the main blade plate 24. The side plate 29 faces the shroud wall 31. The impeller 21A having such a configuration is a so-called closed impeller. The impeller 21A can be applied to the first embodiment, the second embodiment, and the modified examples described above. Therefore, the same or similar effects as those of the first embodiment, the second embodiment, and the modified examples can be obtained.

[0174] <Modification of Blade Plate> The impeller 21A shown in Fig. 10A has the partition member 28 described with reference to Fig. 8A. As shown in Fig. 10A , the partition member 28 is disposed between the side plate 29 and the blade main plate 24. The partition member 28 and the side plate 29 are each fixed to the blade plate 25, for example. This maintains the distance between the blade main plate 24 and the partition member 28, the distance between the partition member 28 and the side plate 29, and the distance between the side plate 29 and the shroud wall 31. In particular, the partition member 28 is located at the boundary between the second region R2 and the third region R3 between the blade main plate 24 and the shroud wall 31.

[0175] In the impeller 21A, the partition member 28 separates the fluid FL flowing in the second region R2 from the fluid FL flowing in the third region R3. Furthermore, the fluid FL flowing in the third region R3 flows from the third region R3 into the second region R2 via the blade opening 28P. This promotes the flow of the fluid FL through the second region R2 and promotes the flow of the fluid FL through the third region R3. This promotes the return flow of the fluid FL in the second region R2 and the third region R3. This reduces the flow rate of the fluid machine.

[0176] The impeller 21A shown in Figure 10B has the partition member 28 described with reference to Figure 8B. Even in this configuration, the partition member 28 can promote the flow of the fluid FL flowing through the second region R2 and the third region R3. This promotes the return flow of the fluid FL in the second region R2 and the third region R3. This allows the flow rate of the fluid machine to be reduced.

[0177] <Sixth Embodiment> <Heat Cycle System> The fluid machines 10 according to the first to fifth embodiments described above can be applied to a heat cycle system. A heat cycle system including the fluid machine 10 will be described with reference to Fig. 11 and Fig. 12. The heat cycle system 70 includes a compressor 71, a condenser 72, an expansion valve 73, an evaporator 74, a first supply pump 75, and a second supply pump 76. The heat cycle system 70 is, for example, a refrigerator or a heat pump.

[0178] The compressor 71 compresses the working fluid vapor A to generate high-temperature, high-pressure working fluid vapor B. The compressor 71 is an example of the fluid machine 10 described above. The working fluid may be, for example, water, a hydrocarbon, or a fluorine-based substance. The fluorine-based substance may be, for example, chlorofluorocarbon. The condenser 72 cools and liquefies the working fluid vapor B discharged from the compressor 71 to generate a low-temperature, high-pressure working fluid C. The condenser 72 may be, for example, a heat exchanger. The shape, type, structure, etc. of the heat exchanger are not particularly limited. The expansion valve 73 expands the working fluid C discharged from the condenser 72 to generate a low-temperature, low-pressure working fluid D. The evaporator 74 heats the working fluid D discharged from the expansion valve 73 to generate a high-temperature, low-pressure working fluid vapor A. The evaporator 74 may be, for example, a heat exchanger. The shape, type, structure, etc. of the heat exchanger are not particularly limited. The first supply pump 75 supplies a load fluid E to the evaporator 74. Here, the load fluid E is, for example, water, antifreeze, air, etc. The second supply pump 76 supplies the fluid FL to the condenser 72.

[0179] Although the embodiments and modifications of the present disclosure have been described above, it should be understood that these are merely illustrative of the present disclosure and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present disclosure. Therefore, the present disclosure should not be considered limited by the foregoing description, but is limited by the scope of the claims.

[0180] According to one aspect of the present disclosure, the flow rate at the same head can be adjusted without changing the rotation speed of the fluid machine and without significantly reducing efficiency, and the flow rate can be adjusted quickly and in a short time.

[0181] 10...Fluid machine, 20...Rotating structure, 21, 21A...Impeller, 22...Rotating shaft, 23...Support member, 24...Blade main plate, 25...Blade plate, 26...Impeller inlet, 27...Impeller outlet, 28...Partition member, 28P...Blade opening, 29...Side plate, 30...Casing, 31...Shroud wall, 32...Main plate side wall, 33...Inlet, 34...Outlet, 35...First member accommodating groove, 36...Second member accommodating groove, 3 7...accommodating portion, 41, 60X...tip portion, 42...dividing portion, 43...gap portion, 50, 50A, 50B, 50C, 50D, 50E, 50F, 50G, 50H...second member, 50AE...end surface, 50AF, 50AS, 50EF, 50FF...plate member, 50BE...end surface, 50BF...elastic member, 50BS...elastic member, 50CL...downstream protrusion, 50CU...upstream protrusion, 50DA, 50FA...shaft Part, 51... Flow area, 40, 40A, 60A, 60B, 60C, 60D, 60E, 60F, 60G, 60H, 60I, 60J... First member, 61... Projection, 62... Base, 62B... Bottom , 62C... Curved surface, 62D... Base downstream surface, 62F... First base, 62K... Inclined surface, 62P... Through hole, 62R... Recessed part, 62S... Second base, 62U... Base upstream surface, 63... First extension part, 64 ...second extension portion, 65...accommodation area, 70...heat cycle system, 71...compressor, 72...condenser, 73...expansion valve, 74...evaporator, 75...first supply pump, 76...second supply pump, D1...first drive unit, D2...second drive unit, DR...downstream area, FL...fluid, FP...flow path, R1...first area, R2...second area, R3...third area, UR...upstream area, US...upstream side, WL...inner wall

Claims

1. A fluid machine comprising: a rotating structure having an impeller having a blade main plate and a blade plate, and a rotating shaft rotatably supporting the impeller; a casing rotatably housing the rotating structure and having a shroud wall facing the blade plate, a main plate side wall facing the blade main plate, an inlet through which a fluid flows, and an outlet through which the fluid flows out; a flow path through which at least a portion of the fluid flows in a first direction from the inlet to the outlet; a first member provided downstream of the impeller between the main plate side wall and the shroud wall, the first member being movable relatively to the shroud wall, and the amount of protrusion into the flow path in the vicinity of the downstream end of the impeller being variable; and a second member disposed on the shroud wall upstream of the impeller in the first direction, the second member being capable of adjusting the flow of fluid along the shroud wall toward the impeller in the first direction.

2. A fluid machinery as described in claim 1, wherein the second member has an upstream surface located upstream of the second member and a downstream surface located downstream of the second member, and the second member is configured to reduce the flow rate of the fluid flowing downstream of the downstream surface, of the fluid flowing along the shroud wall toward the impeller, more than the flow rate of the fluid flowing toward the upstream surface.

3. A fluid machinery as described in claim 2, wherein the second member is movable relative to the shroud wall in a radial direction of the flow passage at a cross section of the flow passage parallel to a direction perpendicular to the first direction, and the second member is configured to reduce a flow rate of the fluid in the vicinity of the shroud wall by moving the second member relative to the shroud wall.

4. A fluid machinery as described in claim 2, wherein the second member has an elastic member that constitutes part of the shroud wall, and the second member is configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by deforming the elastic member.

5. A fluid machinery as described in claim 2, wherein the second member has an upstream protrusion arranged on the inner wall of the flow passage upstream in the first direction, and a downstream protrusion arranged on the inner wall of the flow passage downstream of the upstream protrusion in the first direction, the upstream protrusion and the downstream protrusion are rotatable relative to each other in the circumferential direction of the flow passage in a cross section of the flow passage parallel to a direction perpendicular to the first direction, and the second member is configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by the relative rotation of the upstream protrusion and the downstream protrusion.

6. A fluid machinery as described in claim 2, wherein the second member has an axis portion extending in a direction intersecting the radial direction of the flow passage in a cross section of the flow passage parallel to a direction perpendicular to the first direction and in a direction intersecting the first direction, and the second member is configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by rotating around the axis portion.

7. A fluid machinery as described in claim 2, wherein the second member has an axis portion extending radially of the flow passage in a cross section of the flow passage parallel to a direction perpendicular to the first direction, and the second member is configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by rotating around the axis portion.

8. A fluid machinery as described in claim 2, wherein the impeller has an impeller inlet located upstream of the impeller in the flow path and communicating with the flow path, and the second member is configured to reduce the flow rate of the fluid in the vicinity of the shroud wall by adjusting the distance between the second member and the impeller inlet in the first direction.

9. A fluid machine comprising: a rotating structure having an impeller having a blade main plate and a blade plate, and a rotating shaft rotatably supporting the impeller; a casing rotatably housing the rotating structure and having a shroud wall facing the blade plate, a main plate side wall facing the blade main plate, an inlet through which a fluid flows, and an outlet through which the fluid flows out; a flow path through which at least a portion of the fluid flows in a first direction from the inlet to the outlet; and a first member provided downstream of the impeller between the main plate side wall and the shroud wall, movable relative to the shroud wall, the amount of protrusion into the flow path in the vicinity of the downstream end of the impeller being variable, and having a protrusion protruding toward the upstream side in the first direction.

10. A fluid machine as claimed in claim 1 or claim 9, wherein, when viewed in an axial direction in which the rotating shaft extends, the first member is arranged at a position radially spaced from the rotating shaft.

11. The fluid machinery according to claim 10, wherein the first member has an annular shape when viewed in the axial direction.

12. The fluid machinery according to claim 11, wherein, when viewed in the axial direction, the first member has a circular shape, an oval shape, an elliptical shape, or a polygonal shape.

13. The fluid machinery according to claim 10, wherein the first member has a non-annular shape when viewed in the axial direction.

14. A fluid machine as described in claim 13, wherein, when viewed in the axial direction, the first member has a plurality of divided portions arranged radially from the rotating shaft, and the plurality of divided portions are spaced apart along the circumferential direction of the first member.

15. A fluid machine as described in claim 14, wherein the first member has the plurality of divided portions and gap portions in the circumferential direction where the plurality of divided portions are not formed, and when the area ratio of the first member in the annular shape where no gap portions are formed, as viewed in the axial direction, is 1.0, the total area ratio of the gap portions formed along the circumferential direction, as viewed in the axial direction, is 0.2 or less.

16. A fluid machinery as described in claim 1 or claim 9, wherein the first member has a protrusion protruding toward the upstream side in the first direction and a base extending in the extension direction of the first member, the protrusion having a first extension portion facing the main plate side wall, and the first extension portion being provided on a part of the base and extending from the base towards the impeller.

17. A fluid machinery as described in claim 16, wherein the first member has a second extension portion opposite the first extension portion, the base portion has a storage area accommodated in the shroud wall, and the second extension portion is provided in the storage area.

18. A fluid machinery as described in claim 1 or claim 9, wherein the first member has a protrusion protruding toward the upstream side in the first direction and a base extending in the extension direction of the first member, the base has a base upstream surface facing the impeller, and the protrusion has a recessed portion provided in the base upstream surface.

19. The fluid machinery according to claim 18, wherein the cross-sectional shape of the recessed portion has at least one of a curved portion and an angular portion.

20. A fluid machinery as described in claim 1 or claim 9, wherein the first member has a base extending in the extension direction of the first member, and the base has: a base upstream surface facing the impeller, a base downstream surface opposite the base upstream surface, and a through hole provided in the base so as to extend from the base upstream surface toward the base downstream surface.

21. A fluid machinery as described in claim 1 or claim 9, wherein the first member has a tip portion that is located at the extreme end of the first member protruding into the flow path, and the tip portion is positionable at a minimum position where the first member is contained inside the shroud wall and the amount of protrusion of the first member is minimum, a maximum position where the amount of protrusion of the first member protruding from the shroud wall toward the flow path is maximum, and an intermediate position between the maximum position and the minimum position.

22. The fluid machine according to claim 21, wherein, when the tip portion is disposed at the minimum position, the fluid flows through the flow path from the inlet to the outlet without colliding with the first member.

23. A fluid machine as described in claim 21, wherein, when the tip is positioned at the maximum position or the intermediate position, a first region, a second region, and a third region are generated in the flow passage between the impeller and the shroud wall, and in the first region, the fluid flows through the flow passage from the inlet to the outlet without colliding with the first member, in the second region, the fluid flows toward the first member and collides with the first member, and in the third region, the fluid which has collided with the first member flows in a second direction opposite to the first direction.

24. A fluid machinery as described in claim 23, wherein the impeller has an impeller outlet located downstream of the impeller in the flow passage, the impeller has an impeller inlet located upstream of the impeller in the flow passage and communicating with the flow passage, the impeller has a partition member facing the shroud wall, the partition member having a blade opening located closer to the impeller inlet than the impeller outlet, the partition member is located at the boundary between the second region and the third region, and the fluid flows from the third region to the second region through the blade opening.

25. A fluid machinery as described in claim 23, wherein the impeller has an impeller outlet located downstream of the impeller in the flow path, and with regard to the angle of the blade in the second region near the impeller outlet, when the angle of the blade is 0 degrees relative to the radial direction of the impeller and is a positive value relative to the rotational direction of the impeller, the maximum value of the angle of the blade is 0 degrees or a positive value.

26. A fluid machinery as described in claim 23, wherein the impeller has an impeller outlet located downstream of the impeller in the flow path, and with regard to the angle of the blade in the third region near the impeller outlet, when the angle of the blade is 0 degrees relative to the radial direction of the impeller and is a positive value relative to the rotational direction of the impeller, the minimum value of the angle of the blade is 0 degrees or a negative value.

27. A fluid machinery as described in claim 23, wherein the first member has a base extending in an extension direction of the first member, the base having a base upstream surface facing the impeller, a base downstream surface opposite the base upstream surface, and a through hole provided in the base so as to extend from the base upstream surface toward the base downstream surface, and a portion of the fluid flowing through the flow path flows through the through hole in a second direction opposite to the first direction, reaches the base upstream surface, and joins the fluid flowing in the second region.

28. A fluid machinery as described in claim 27, wherein the fluid flowing through the through hole in the second direction and the fluid flowing in the second region merge to generate a merged fluid on the upstream surface of the base, and the merged fluid accelerates the flow of the fluid in the third region.

29. A fluid machinery according to claim 1 or claim 9, further comprising a first drive section connected to the first member for moving the first member relatively to the shroud wall.

30. The fluid machinery according to claim 1, further comprising a second drive section connected to the second member for moving the second member relatively to the shroud wall.

31. A fluid machinery as described in claim 30, further comprising a first drive unit connected to the first member and configured to move the first member relatively to the shroud wall, wherein the first drive unit and the second drive unit move the first member and the second member so that the first member and the second member are synchronized with each other.

32. A fluid machinery as described in claim 1, further comprising a drive unit which moves the first member and the second member, the drive unit being connected to the first member and moving the first member relatively to the shroud wall, the drive unit being connected to the second member and moving the second member relatively to the shroud wall, and the drive unit moving the first member and the second member so that the first member and the second member are synchronized with each other.

33. A fluid machinery according to claim 1 or claim 9, wherein the impeller has a side plate joined to the blade plate so as to be spaced apart from the main blade plate, and the side plate faces the shroud wall.

34. A heat cycle system comprising the fluid machine according to claim 1 or 9.

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