Radial turbine, exhaust component of radial turbine, rotary machine, exhaust component of rotary machine

Abstract

Provided are a radial turbine, an exhaust member of a radial turbine, a rotary machine, and an exhaust member of a rotary machine, which aim to reduce regions where separation occurs in a flow path and improve the efficiency of pressure recovery in a diameter-expanded flow path. A radial turbine (10A) includes: a rotor (12) disposed so as to be rotatable about a center axis (C); a rotating blade (13) fixed to an outer peripheral portion of the rotor (12); a casing (11) disposed on an outer peripheral side of the rotor (12) and the rotating blade (13) and forming a flow path of a working fluid on an inner side thereof; a reduced flow path portion (16) disposed at a position on a downstream side of the rotating blade (13) in a flow direction of the working fluid and gradually reducing a cross-sectional area of the flow path of the working fluid toward the downstream side; and an expanded flow path portion (17) disposed on a downstream side of the reduced flow path portion (16) and gradually expanding the cross-sectional area of the flow path of the working fluid toward the downstream side.

Description

[0001] This application is a divisional application of the following patent application: Application Number: 201880003439.6 Application date: February 7, 2018 Invention Title: Rotating Machinery, Exhaust Components for Rotating Machinery Technical Field

[0002] This invention relates to a rotating machine and an exhaust component for the rotating machine. Background Technology

[0003] Rotating machinery such as radial-flow turbines (centrifugal turbines) or axial-flow turbines used in turbochargers, and axial-flow blowers for blast furnaces, comprises a housing, a rotor rotatably disposed within the housing, and blades disposed on the outer periphery of the rotor. Some of these rotating machines utilize externally supplied working fluid to rotate the bladed rotor. Others utilize externally transmitted power to rotate the bladed rotor and deliver the working fluid.

[0004] However, in such rotating machinery, from a performance point of view, it is desirable to efficiently convert the velocity of the working fluid passing through the blades into pressure.

[0005] Therefore, for example, as disclosed in Patent Document 1, a structure is often adopted in which an expanding flow path (diffuser) with a gradually increasing cross-sectional area is used in the exhaust flow path of the working fluid. By setting up such an expanding flow path, the pressure of the compressed working fluid can be gradually reduced and discharged to, for example, atmospheric pressure.

[0006] Previous technical documents Patent documents Patent Document 1: Japanese Patent No. 5040156. Summary of the Invention

[0007] The technical problem to be solved by the invention For example, such as Figure 11 As shown, in the case of the radial turbine 1 used in the turbocharger, the working fluid changes direction as it flows along the impeller 3 from the outer periphery of the housing 2 and is discharged from the inner periphery of the impeller 3 along the central axis. In this case, downstream of the central portion 3c of the impeller 3, a portion of the working fluid flowing out from the inner periphery of the impeller 3 along the central axis detaches to form a stripping vortex. The region S1 where this stripping vortex is generated does not function as a flow path for the working fluid. Therefore, in the expanded-diameter flow path 4 downstream of this region where the stripping vortex is generated, the efficiency of pressure recovery is impaired.

[0008] And, as Figure 12As shown, in the case of an axial flow blower 5, etc., there is a situation where the working fluid flowing between the housing 6 and the rotor 7 disposed within the housing 6 experiences stripping on the downstream side of the moving blade 8A or the fixed blade 8B. For example, when stripping occurs in the working fluid flowing along the surface of the rotor 7 on the downstream side of the fixed blade 8B, the stripped area S2 essentially does not function as a flow path for the working fluid. Therefore, in the expanded diameter flow path 9, which is affected by the stripped area S2 on its downstream side, the efficiency of pressure recovery is impaired.

[0009] The present invention was made in view of this situation, and its object is to provide a rotating machine and an exhaust component of the rotating machine that can reduce the area of ​​stripping in the flow path and improve the efficiency of pressure recovery in the expanded flow path.

[0010] means for solving technical problems To solve the above-mentioned problems, the rotating machinery and the exhaust component of the rotating machinery of the present invention employ the following means.

[0011] One aspect of the present invention relates to a rotating machine comprising: a rotor rotatable about a central axis; rotating blades fixed to the outer periphery of the rotor; a housing disposed on the outer periphery of the rotor and the rotating blades, and forming a flow path for a working fluid on its inner side; a narrowing flow path portion disposed downstream of the rotating blades in the flow direction of the working fluid, wherein the cross-sectional area of ​​the flow path of the working fluid gradually decreases toward the downstream side; and an expanding flow path portion disposed downstream of the narrowing flow path portion, wherein the cross-sectional area of ​​the flow path of the working fluid gradually increases toward the downstream side.

[0012] According to the rotating machinery described in this method, the flow path of the working fluid is narrowed by providing a flow-reducing section located downstream of the rotating blades in the flow direction of the working fluid. As a result, in the narrowed section, the area downstream of the rotating blades where stripping may occur is relatively reduced relative to the area where the working fluid actually flows. This reduces the area where stripping of the working fluid occurs within the flow path. After this flow-reducing section, the cross-sectional area of ​​the working fluid flow path is gradually increased by widening the flow-reducing section, thereby improving the efficiency of pressure recovery of the working fluid.

[0013] In the aforementioned rotating machinery, a discharge section is further provided, which extends downstream of the rotor and the rotating blades and discharges the working fluid downstream. It is even more preferable that the narrowing flow path section and the widening flow path section are formed in the discharge section at a position further downstream of the end of the rotor in the flow direction.

[0014] In this type of rotating machinery, stripping of the working fluid is prone to occur at the downstream end of the rotor. In this structure, by providing a narrowed flow path section located further downstream than the downstream end of the rotor, the area where stripping of the working fluid occurs can be effectively reduced.

[0015] In the aforementioned rotating machinery, the housing and the rotor extend toward the downstream side of the flow direction more than the rotating blades, and it is further preferred that the narrowed flow path is formed on at least one side of the housing and the rotor more than the downstream side of the rotating blades.

[0016] According to this rotating machinery, in a structure in which the housing and rotor extend continuously to a downstream side than the rotating blades, the area where working fluid is stripped can be effectively reduced.

[0017] The aforementioned rotating machinery also includes a fixed blade, which is located further downstream than the rotating blade and extends from the housing toward the inner circumference. It is further preferred that the narrowed flow path is formed in the region where the fixed blade is located in the flow direction.

[0018] According to this rotating machinery, the area where the working fluid is stripped can be reduced in the fixed blade section located on the downstream side of the rotating blade.

[0019] The aforementioned rotating machinery also includes a fixed blade, which is positioned upstream of the rotating blade and extends from the housing toward the inner circumference. It is further preferred that the narrowing flow path is positioned downstream of the working fluid flow direction, which is closer to the rotating blade than the rotating blade.

[0020] According to this rotating machinery, the area where the working fluid is stripped can be reduced in the portion located on the downstream side of the rotating blades.

[0021] An exhaust component for a rotating machine according to one aspect of the present invention comprises: a rotor rotatable about a central axis; rotating blades fixed to the outer periphery of the rotor; and a housing disposed on the outer periphery of the rotating blades and having a flow path for a working fluid formed therein. The exhaust component of the rotating machine further comprises: a cylindrical exhaust component body extending downstream of the rotor and the rotating blades, forming an exhaust flow path for discharging the working fluid downstream; a narrowing flow path portion formed on the inner periphery of the exhaust component body, with the cross-sectional area of ​​the flow path gradually decreasing downstream of the flow direction of the working fluid; and an expanding flow path portion formed on the inner periphery of the exhaust component body, further downstream of the narrowing flow path portion, with the cross-sectional area of ​​the flow path gradually increasing downstream.

[0022] According to the exhaust component of the rotating machinery involved in this method, by providing such an exhaust component, it is equivalent to setting a narrowed flow path section at a position downstream of the flow direction of the working fluid, which is closer to the rotating blades. This reduces the area within the flow path where working fluid stripping occurs.

[0023] Invention Effects According to the rotating machinery and exhaust components of the rotating machinery involved in the present invention, it is possible to reduce the area of ​​stripping generated in the flow path and improve the efficiency of pressure recovery in the expanded flow path. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view showing the structure of the radial turbine used in the turbocharger according to the first embodiment of the present invention.

[0025] Figure 2 This is a diagram showing the flow path area in the radial turbine used in the turbocharger according to the first embodiment of the present invention.

[0026] Figure 3 This is a cross-sectional view showing the structure of the radial turbine used in a turbocharger according to a variation of the first embodiment of the present invention.

[0027] Figure 4 This is a diagram showing the flow path area in the radial turbine used in a turbocharger according to a variation of the first embodiment of the present invention.

[0028] Figure 5 This is a cross-sectional view showing the structure of the axial flow blower according to the second embodiment of the present invention.

[0029] Figure 6 This is a cross-sectional view showing the structure of the axial flow blower according to the third embodiment of the present invention.

[0030] Figure 7 This is a cross-sectional view showing the structure of an axial flow blower according to a modified example of the third embodiment of the present invention.

[0031] Figure 8 This is a cross-sectional view showing the structure of the axial flow turbine according to the fourth embodiment of the present invention.

[0032] Figure 9 This is a graph showing the flow velocity distribution in an embodiment of the present invention.

[0033] Figure 10 This is a graph showing the flow velocity distribution in a comparative example of the present invention.

[0034] Figure 11This is a cross-sectional view showing the structure of the radial turbine used in conventional turbochargers.

[0035] Figure 12 This is a cross-sectional view showing the structure of a conventional axial flow blower. Detailed Implementation

[0036] Hereinafter, an embodiment of the rotating machinery and the exhaust component of the rotating machinery according to the present invention will be described with reference to the accompanying drawings.

[0037] [First Embodiment] The following uses Figure 1 The first embodiment of the present invention will be described.

[0038] like Figure 1 As shown, the radial flow turbine (rotating machinery) 10A used in the turbocharger has a housing 11, a rotor 12 and rotating blades 13.

[0039] The housing 11 forms the outer shell of the radial flow turbine 10A. The housing 11 includes: a hollow rotor housing 11R that houses the rotor 12; and an exhaust component (exhaust section, exhaust component body) 15A arranged to surround the outer periphery of the rotating blades 13.

[0040] Furthermore, the housing 11 is connected to an intake housing or stationary blade having an intake port (not shown) that draws in working fluids such as exhaust gas from the internal combustion engine from the radial outside.

[0041] The rotor 12 includes: a rotating shaft 12s that is rotatably supported within the housing 11 via a bearing (not shown) about a central axis C; and a disk portion 14 disposed at one end of the rotating shaft 12s in the direction of the central axis C.

[0042] The wheel portion 14 includes: a bore portion 14b formed in the central portion including the central shaft C; and a deflection surface 14f formed on the outer peripheral side of the bore portion 14b facing the direction of the central shaft C. The deflection surface 14f is formed by a concave curved surface whose outer diameter gradually increases from one side to the other in the direction of the central shaft C, so that the flow direction of the working fluid taken in from the radially outer air intake 11a toward the radially inner side is deflected toward the direction of the central shaft C.

[0043] Multiple rotating blades 13 are provided on the deflection surface 14f of the disk portion 14 at intervals along the circumference around the central axis C.

[0044] The housing 11 described above has a protective cover 18 provided in such a way that a plurality of rotating blades 13 are covered on one side from the direction of the central axis C.

[0045] The exhaust component 15A is provided continuously with the shroud portion 18 at a position downstream of the flow direction of the working fluid, i.e., on the side in the direction of the central axis C, which is closer to the flow direction of the rotating blade 13. The exhaust component 15A is cylindrical and has an exhaust flow path 102 formed on its inner side for the working fluid to flow from the inner circumferential side of the disc portion 14 (the outer circumferential side of the hole portion 14b) toward the side in the direction of the central axis C (downstream side).

[0046] The exhaust component 15A has a narrowing flow path 16 and an enlarged flow path 17 located downstream of the narrowing flow path 16 on its inner circumferential surface 15f. The narrowing flow path 16 and the enlarged flow path 17 are formed in the exhaust component 15A at a position further downstream than the end face (end) 14g of the hole 14b located downstream of the flow direction of the rotor 12.

[0047] The narrowing flow path 16 is formed such that its inner diameter gradually decreases towards the downstream side, thereby gradually reducing the cross-sectional area of ​​the working fluid. The widening flow path 17 is formed continuously downstream of the narrowing flow path 16, and is formed such that its inner diameter gradually increases towards the downstream side, thereby gradually increasing the cross-sectional area of ​​the working fluid.

[0048] In the radial-flow turbine 10A described above, the working fluid taken in from the intake port 11a flows radially outward and inward into the flow path 101 between the deflection surface 14f of the disc portion 14 and the shroud portion 18. The working fluid flowing into this flow path 101 collides with the rotating blades 13, causing the rotor 12 to rotate around its central axis, thereby driving a compressor (not shown) connected to the other end of the rotor 12. The working fluid flows out from the inner circumferential side of the disc portion 14 (outer circumferential side of the bore portion 14b) towards the central axis C (downstream side), and is discharged to the outside through the exhaust flow path 102 inside the exhaust component 15A.

[0049] Here, within the exhaust component 15A, a portion of the working fluid flowing along the deflection surface 14f of the wheel portion 14 peels off at the downstream side of the end face 14g of the hole portion 14b of the wheel portion 14, generating vortices. Consequently, a region S21 for generating peeling vortices is formed on the downstream side of the end face 14g of the hole portion 14b. On the other hand, within the exhaust component 15A, the working fluid flowing downstream along the central axis C is deflected radially inward by the narrowing flow path 16 formed on the inner circumferential surface 15f. The working fluid passing through the narrowing flow path 16 gradually decreases in velocity as its flow path cross-sectional area gradually increases in the widening flow path 17, and is released from the outlet of the exhaust component 15A into the external atmosphere, for example, atmospheric pressure.

[0050] As a result, the radial dimension of the region S21 in which the stripping vortex is generated in the center of the exhaust flow path 102 formed in the exhaust component 15A by having the reduced flow path section 16 becomes smaller, and the cross-sectional area (hereinafter referred to as the effective flow path area) of the region S22 in which the working fluid flows downstream on the outer periphery of the region S21 becomes relatively larger.

[0051] Figure 2 This refers to the flow path area M1 of the exhaust component 15A, the effective flow path area M2 of the region S22 where the working fluid flows, excluding the region S21 where the stripping vortex is generated, and the flow path area 16 when it is not equipped with a narrowing section. Figure 11 The diagram shown illustrates the effective flow path area M0 of the working fluid flow region excluding the stripped vortex region S21. Figure 2 As shown, by having the narrowed flow path section 16, the effective flow path area M2 of the working fluid flow area S22 becomes larger.

[0052] According to the radial-flow turbine 10A and exhaust component 15A described above, the flow path 102 of the working fluid is narrowed by providing a narrowing flow path section 16 located downstream of the rotating blade 13 in the flow direction of the working fluid. As a result, in the narrowed flow path section, the area S21 downstream of the rotating blade 13 where stripping may occur is relatively reduced relative to the area S22 where the working fluid substantially flows. This reduces the area S21 where working fluid stripping occurs within the flow path. After this narrowing flow path section 16, the cross-sectional area of ​​the working fluid flow path is gradually increased by widening the flow path section 17, thereby improving the efficiency of working fluid pressure recovery.

[0053] Furthermore, by providing a narrowing flow path section 16 on the downstream side of the end face 14g on the downstream side of the hole section 14b of the disc section 14, the area S21 where working fluid is stripped can be effectively reduced.

[0054] [Modifications of the first embodiment] like Figure 3 As shown, the exhaust component (discharge section, exhaust component body) 15B of the radial-flow turbine (rotating machinery) 10B used in the turbocharger is provided continuously with the shroud portion 18 of the housing 11, located downstream of the flow direction of the working fluid, i.e., on the side in the direction of the central axis C, further downstream than the rotating blades 13. The exhaust component 15B is cylindrical and has an exhaust flow path 102 formed on its inner side for the working fluid to flow from the inner circumference of the disc portion 14 (the outer circumference of the orifice portion 14b) toward the downstream side.

[0055] The exhaust component 15B has a straight flow path 20, a first enlarged flow path 21, a narrowed flow path 22, and a second enlarged flow path 23 disposed downstream of the narrowed flow path 22 on its inner circumferential surface 15f from the upstream side toward the downstream side. These first enlarged flow path 21, narrowed flow path 22, and second enlarged flow path 23 are formed in the exhaust component 15B at a position further downstream than the end face 14g of the hole 14b located downstream of the flow direction of the rotor 12.

[0056] The straight flow path 20 has a constant inner diameter in the direction of the central axis C.

[0057] The first enlarged flow path section 21 is formed such that the cross-sectional area of ​​the flow path of the working fluid gradually increases as its inner diameter gradually expands towards the downstream side.

[0058] The narrowing flow path section 22 is formed such that its inner diameter gradually decreases towards the downstream side, thereby gradually reducing the cross-sectional area of ​​the working fluid. The second widening flow path section 23 is formed continuously to the downstream side of the narrowing flow path section 22, and is formed such that its inner diameter gradually increases towards the downstream side, thereby gradually increasing the cross-sectional area of ​​the working fluid.

[0059] Figure 4 This refers to the flow path area M11 of the exhaust component 15B, the effective flow path area M12 of the working fluid flow area S22 excluding the region S21 where stripping vortices are generated, and the flow path area 22 when it is not equipped with a narrowing section ( Figure 11 The diagram shown illustrates the effective flow path area M0 of the working fluid flow region excluding the stripped vortex region S21. Figure 4 As shown, by having a narrowed flow path section 22, the effective flow path area M12 of the working fluid flow area S22 becomes larger.

[0060] In this exhaust component 15B, similar to the exhaust component 15A of the first embodiment described above, the area S21 where stripping may occur downstream of the rotating blade 13 can be reduced by providing the narrowing flow path section 22, and the effective flow path cross-sectional area of ​​the area S22 where the working fluid substantially flows can be increased. After this narrowing flow path section 22, the flow path cross-sectional area of ​​the working fluid is gradually increased by the second widening flow path section 23, thereby improving the efficiency of pressure recovery of the working fluid.

[0061] [Second Implementation] Next, a second embodiment of the rotating machinery and the exhaust component of the rotating machinery according to the present invention will be described. Furthermore, in the following description, structures common to the first embodiment described above will be labeled with the same symbols and their descriptions will be omitted.

[0062] like Figure 5As shown, the axial flow blower (rotating machinery) 10C includes a housing 31C, a rotating shaft (rotor) 32, moving blades (rotating blades) 33, and fixed blades 34.

[0063] The shell 31C is cylindrical, extending along the central axis C.

[0064] The rotating shaft 32 is supported by a bearing (not shown) inside the housing 31C in a manner that allows it to rotate about the central axis C. This rotating shaft 32 is driven by a turbine (not shown) or similar device in a manner that allows it to rotate about the central axis C.

[0065] The annular region between the inner circumferential surface of these housings 31C and the outer circumferential surface of the rotating shaft 32 forms the flow path 103 for the working fluid.

[0066] Multiple moving blades 33 are provided at intervals around the central axis C on the outer periphery of the rotating shaft 32. Each moving blade 33 is formed to extend radially outward from the outer periphery of the rotating shaft 32.

[0067] Fixed blades 34 are disposed downstream of moving blades 33 along the central axis C. Multiple fixed blades 34 are spaced apart circumferentially around the central axis C on the inner side of housing 31C. Each fixed blade 34 extends from housing 31C toward its inner circumference.

[0068] The aforementioned housing 31C and rotating shaft 32 extend downstream in the flow direction than the moving blades 33 and fixed blades 34. In the housing 31C, a narrowing flow path section 36C and an expanding flow path section 37 are formed at a position further downstream than the moving blades 33 and fixed blades 34.

[0069] These narrowing flow path sections 36C and widening flow path sections 37 are formed on the inner peripheral surface 31f of the housing 31C. The narrowing flow path section 36C gradually narrows towards the downstream side along the inner diameter of the housing 31C, thus reducing the cross-sectional area of ​​the working fluid flow path. Here, as... Figure 5 As shown, the narrowed flow path section 36C can be formed in the area where a fixed blade 34 is provided in the flow direction.

[0070] The enlarged flow path section 37 is located downstream of the narrowed flow path section 36C, and the cross-sectional area of ​​the flow path of the working fluid gradually increases as the inner diameter of the housing 31C gradually expands towards the downstream side.

[0071] According to the axial flow blower 10C described above, the flow path of the working fluid is narrowed by providing a narrowing flow path section 36C downstream of the flow direction of the working fluid passing through the moving blades 33 and the fixed blades 34. As a result, in the narrowed flow path section, the cross-sectional area S22 of the region where the working fluid substantially flows in the flow path 103 between the housing 31C and the rotating shaft 32 becomes relatively larger. Consequently, the area S21 where delamination may occur downstream of the moving blades 33 is relatively reduced. After passing through this narrowing flow path section 36C, the cross-sectional area of ​​the working fluid flow path gradually increases by widening the flow path section 37, thereby improving the efficiency of pressure recovery of the working fluid.

[0072] [Third Implementation] Next, a third embodiment of the rotating machinery and the exhaust component of the rotating machinery according to the present invention will be described. Furthermore, in the following description, structures common to the second embodiment described above will be labeled with the same symbols and their descriptions will be omitted.

[0073] like Figure 6 As shown, the axial flow blower (rotating machinery) 10D includes a housing 31D, a rotating shaft (rotor) 32D, moving blades 33, and fixed blades 34.

[0074] The shell 31D is cylindrical, extending along the central axis C.

[0075] The rotating shaft 32D is supported by a bearing (not shown) inside the housing 31D in a manner that allows it to rotate about the central axis C. This rotating shaft 32D is driven by a turbine (not shown) or similar device in a manner that allows it to rotate about the central axis C.

[0076] The annular region between the inner circumferential surface of these housings 31D and the outer circumferential surface of the rotating shaft 32D forms the flow path 103 for the working fluid.

[0077] Multiple moving blades 33 are provided at intervals around the central axis C on the outer periphery of the rotating shaft 32D. Each moving blade 33 is formed to extend radially outward from the outer periphery of the rotating shaft 32D.

[0078] Fixed blades 34 are disposed downstream of moving blades 33 in the direction of central axis C. Multiple fixed blades 34 are provided at intervals along the circumferential direction around central axis C on the inner side of housing 31D. Each fixed blade 34 is formed to extend from housing 31D toward the inner circumferential side.

[0079] The aforementioned housing 31D and rotating shaft 32D extend downstream in the flow direction than the moving blades 33 and fixed blades 34. A narrowed flow path 36D is formed on the outer peripheral surface of the rotating shaft 32D, further downstream than the moving blades 33 and fixed blades 34. Furthermore, an enlarged flow path 37 is formed on the inner peripheral surface of the housing 31D, further downstream than the narrowed flow path 36D.

[0080] The flow path section 36D expands downstream through the outer diameter of the rotating shaft 32D, while the cross-sectional area of ​​the working fluid gradually decreases. Here, as... Figure 6 As shown, the narrowed flow path section 36D is formed in the area where a fixed blade 34 is provided in the flow direction.

[0081] The enlarged flow path section 37 is located downstream of the reduced flow path section 36D, and the cross-sectional area of ​​the flow path of the working fluid gradually increases as the inner diameter of the housing 31D gradually expands towards the downstream side.

[0082] According to the axial flow blower 10D described above, the flow path of the working fluid is narrowed by providing a narrowing flow path section 36D downstream of the flow direction of the working fluid passing through the moving blades 33 and the fixed blades 34. As a result, in the narrowed flow path section, the cross-sectional area S32 of the region where the working fluid actually flows in the flow path 103 between the housing 31D and the rotating shaft 32D becomes relatively larger. Consequently, the area S31 where stripping may occur downstream of the moving blades 33 is relatively reduced. After passing through this narrowing flow path section 36D, the cross-sectional area of ​​the working fluid flow path gradually increases by widening the flow path section 37, thereby improving the efficiency of pressure recovery of the working fluid.

[0083] [Modifications of the third embodiment] Furthermore, in the third embodiment described above, the narrowing flow path section 36D is provided in the region where the fixed blade 34 is provided in the flow direction, but it is not limited to this.

[0084] For example, such as Figure 7 As shown, the narrowed flow path 36E of the rotating shaft (rotor) 32E formed in the axial flow blower (rotor machinery) 10E can also be set at a position further downstream than the fixed blade 34.

[0085] [Fourth Implementation] Next, a fourth embodiment of the rotating machinery and the exhaust component of the rotating machinery according to the present invention will be described.

[0086] like Figure 8 As shown, the axial flow turbine (rotating machinery) 10F includes a turbine housing 41, a rotor 42, fixed blades 43, moving blades (rotating blades) 44, and an exhaust housing (casing) 45.

[0087] The turbine housing 41 is cylindrical, extending along the central axis C.

[0088] Multiple fixed blades 43 are provided at intervals along the circumferential direction around the central axis C on the inner side of the turbine housing 41. Each fixed blade 43 is formed in such a way that it extends from the turbine housing 41 toward the inner circumferential side.

[0089] The rotor 42 is supported by a bearing (not shown) in a manner that allows it to rotate about the central axis C.

[0090] Multiple moving blades 44 are provided at intervals around the central axis C on the outer periphery of the rotor 42. Each moving blade 44 is formed to extend radially outward from the outer periphery of the rotor 42. The moving blades 44 are arranged downstream of the fixed blades 43 in the direction of the central axis C.

[0091] The exhaust casing 45 is connected to the downstream side of the turbine housing 41. The exhaust casing 45 includes: an outer peripheral casing portion 45a located radially outward of the moving blade 44; and an inner peripheral casing portion 45b disposed radially inward relative to the outer peripheral casing portion 45a. The inner peripheral casing portion 45b is cylindrical, extending along the central axis C, and is disposed on the outer peripheral side of the rotation shaft 42s of the rotor 42. An annular cross-sectional area between the inner peripheral surface of the outer peripheral casing portion and the outer peripheral surface of the inner peripheral casing portion 45b of the exhaust casing 45 forms an exhaust flow path 104 for the working fluid.

[0092] The aforementioned exhaust casing 45 extends downstream in the flow direction than the fixed blades 43 and the moving blades 44. A narrowing flow path 46 is formed on the outer peripheral surface of the inner peripheral casing portion 45b, further downstream than the fixed blades 43 and the moving blades 44. Furthermore, an enlarging flow path 47 is formed on the inner peripheral surface of the turbine casing 41, further downstream than the narrowing flow path 46.

[0093] The flow path section 46 gradually reduces the cross-sectional area of ​​the working fluid as the outer diameter of the inner peripheral housing section 45b expands towards the downstream side.

[0094] The enlarged flow path section 47 is located downstream of the narrowed flow path section 46, and the cross-sectional area of ​​the flow path of the working fluid gradually increases as the inner diameter of the outer peripheral housing section 45a and the outer diameter of the inner peripheral housing section 45b gradually increase towards the downstream side.

[0095] According to the axial flow turbine 10F described above, the flow path of the working fluid is narrowed by providing a narrowing flow path section 46 downstream of the flow direction of the working fluid passing through the fixed blades 43 and the moving blades 44. As a result, the area where stripping may occur downstream of the moving blades 44 is relatively reduced. After passing through this narrowing flow path section 46, the cross-sectional area of ​​the working fluid is gradually increased by the widening flow path section 47, thereby improving the efficiency of pressure recovery of the working fluid.

[0096] Furthermore, while the above embodiments illustrate radial-flow turbines 10A and 10B, axial-flow blowers 10C and 10D, and axial-flow turbine 10F, the present invention is also applicable to rotating machinery other than those described above, such as mixed-flow turbines. Moreover, the structures of each component of the radial-flow turbines 10A and 10B, the axial-flow blowers 10C and 10D, and the axial-flow turbine 10F can be configured differently from those shown in the above embodiments and their variations.

[0097] Furthermore, as long as the flow reduction section is located downstream of the working fluid flow direction, which is closer to the rotating blade, the convex shape forming the flow reduction section can be provided on either the housing side or the rotor side, or the convex shape can be provided on both the housing side and the rotor side.

[0098] In addition, the housing can be made up of a single component or by combining multiple components.

[0099] Example The effect of the structure shown in the first embodiment described above has been confirmed, and therefore, the results are shown below.

[0100] As an example, an L-shaped exhaust component is used. This exhaust component has a narrowing flow path on the upstream side of an enlarged flow path that gradually increases in inner diameter toward the downstream side.

[0101] As a comparative example, an exhaust component was used that does not have a reduced flow path section on the upstream side of the expanded flow path section, but has an inner diameter that gradually decreases towards the downstream side.

[0102] The flow velocity distribution inside the exhaust component was determined by computer analysis for the above embodiments and comparative examples.

[0103] The results are shown in Figure 9 and Figure 10 .

[0104] As shown in Figure 9, in the embodiment with the reduced flow path, and Figure 10 Compared to the comparative example shown, the flow path section with low flow velocity in the central part of the flow path is narrowed. Therefore, the area where stripping occurs within the flow path is reduced, and the efficiency of pressure recovery is improved by widening the flow path section downstream of it.

[0105] Symbol Explanation 10A, 10B - Radial flow turbine (rotating machinery), 10C, 10D, 10E - Axial flow blower (rotating machinery), 10F - Axial flow turbine (rotating machinery), 11 - Housing, 12 - Rotor, 13 - Rotating blade, 14g - End face (end), 15A, 15B - Exhaust component (discharge section, exhaust component body), 15f - Inner circumferential surface, 16, 22, 36C, 36D, 36E - Narrowing flow path section, 17, 37 - Enlarging flow path section, 23 - Second enlarging flow path section (enlarging flow path section), 31C, 31D - Housing, 31f - Inner circumferential surface, 32, 32D, 32E - Rotating shaft (rotor), 33 - Moving blade (rotating blade), 34 - Fixed blade, 42 - Rotor, 43 - Fixed blade, 44 - Moving blade (rotating blade), 45 - Exhaust housing (housing), C - Central shaft.

Claims

1. A radial-flow turbine, characterized in that, have: A rotor that is configured to rotate about a central axis; Rotating blades, which are fixed to the outer periphery of the rotor; A housing is disposed on the outer periphery of the rotor and the rotating blades, and a flow path for the working fluid is formed on its inner side; A straight flow path is provided in the housing at a position downstream of the flow direction of the working fluid, which is closer to the rotating blades. A first enlarged flow path section is provided continuously in the housing on the downstream side of the straight flow path section, and the cross-sectional area of ​​the flow path of the working fluid gradually increases towards the downstream side; A narrowing flow path section is provided in the housing continuously downstream of the first enlarged flow path section, and the cross-sectional area of ​​the flow path of the working fluid gradually decreases towards the downstream side; as well as The second enlarged flow path section is provided continuously in the housing on the downstream side of the reduced flow path section, and the cross-sectional area of ​​the flow path of the working fluid gradually increases towards the downstream side.

2. The radial-flow turbine according to claim 1, characterized in that, It also has: The discharge section extends downstream of the rotor and the rotating blades, and discharges the working fluid downstream. The first enlarged flow path, the narrowed flow path, and the second enlarged flow path are formed in the discharge section at a position further downstream than the end of the rotor in the flow direction.

3. The radial-flow turbine according to claim 1, characterized in that, A disc portion with a hole is provided at the downstream end of the rotor. In the direction in which the central axis extends, the position of the straight flow path corresponds to the position of the hole.

4. An exhaust component for a radial-flow turbine, the radial-flow turbine comprising: a rotor rotatable about a central axis; rotating blades fixed to the outer periphery of the rotor; and a housing disposed on the outer periphery of the rotating blades, and having a flow path for the working fluid formed therein. Its features are, have: A cylindrical exhaust component body is provided to extend downstream of the rotor and the rotating blades, and forms an exhaust flow path for discharging the working fluid downstream. A straight flow path is formed on the inner circumferential surface of the exhaust component body, located downstream of the flow direction of the working fluid, and has a constant inner diameter. The first enlarged flow path is continuously formed on the inner circumferential surface of the exhaust component body at a position further downstream than the straight flow path, and the cross-sectional area of ​​the flow path of the working fluid gradually increases towards the downstream side. A narrowed flow path is formed continuously on the inner circumferential surface of the exhaust component body at a position further downstream than the first enlarged flow path, and the cross-sectional area of ​​the flow path of the working fluid gradually decreases towards the downstream side. as well as The second enlarged flow path is continuously formed on the inner circumferential surface of the exhaust component body at a position further downstream than the reduced flow path, and the cross-sectional area of ​​the flow path of the working fluid gradually increases towards the downstream side.

5. A rotating machine, characterized in that, have: A rotor that is configured to rotate about a central axis; Rotating blades, which are fixed to the outer periphery of the rotor; A housing is disposed on the outer periphery of the rotor and the rotating blades, and a flow path for the working fluid is formed on its inner side; A reduced flow path section is provided in the housing at a position downstream of the flow direction of the working fluid, which is closer to the rotating blades, and the cross-sectional area of ​​the flow path of the working fluid gradually decreases towards the downstream side. as well as An enlarged flow path section is continuously formed in the housing on the downstream side of the narrowed flow path section, and the cross-sectional area of ​​the flow path for the working fluid gradually increases towards the downstream side. The housing and the rotor extend downstream of the flow direction than the rotating blades. The rotating mechanism also includes a fixed blade, which is positioned further downstream than the rotating blade and extends from the housing toward the inner circumference. The narrowed flow path is formed in the region where the fixed blades are provided in the flow direction.

6. An exhaust component for a rotating machine, the rotating machine comprising: a rotor rotatable about a central axis; rotating blades fixed to the outer periphery of the rotor; and a housing disposed on the outer periphery of the rotating blades, and having a flow path for a working fluid formed therein. Its features are, have: A cylindrical exhaust component body is provided to extend downstream of the rotor and the rotating blades, and forms an exhaust flow path for discharging the working fluid downstream. A narrowed flow path is formed on the inner circumferential surface of the exhaust component body, and the cross-sectional area of ​​the flow path of the working fluid gradually decreases in the downstream direction of the flow direction of the working fluid. An enlarged flow path is formed continuously on the inner circumferential surface of the exhaust component body at a position further downstream than the reduced flow path, and the cross-sectional area of ​​the flow path of the working fluid gradually increases towards the downstream side. as well as A fixed blade is positioned further downstream than the rotating blade and extends from the housing toward the inner circumference. The narrowed flow path is formed in the region where the fixed blades are provided in the flow direction.

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