Turbine and governor device

Abstract

To extract more energy than when two blades with an arcuate cross section, each having an inner peripheral surface that has a constant thickness and is semicircular in cross section, are used to extract energy from fluid flowing through a pipe.SOLUTION: A turbine is arranged inside a pipe so as to be rotatable around a rotational axis perpendicular to a flow direction of fluid flowing inside the pipe, and comprises blades whose orthogonal cross section perpendicular to the rotation axis is formed into an arch shape. In the orthogonal cross section, an inner peripheral surface of the blade is semicircular, the center of the inner peripheral surface is away from the rotational axis, and the rotational axis is arranged between both ends of the inner peripheral surface, and there are three or more blades, where, when viewed from a direction of the rotational axis, each of the blades is arranged at equal intervals in a circumferential direction of the rotational axis.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a turbine and a governor device. [Background technology]

[0002] Non-Patent Document 1 discloses a configuration in which a Savonius turbine is arranged on a water supply pipe to extract energy. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] S. Abdolkarim Payambarpour, Amir F. Najafi, Franco Magagnato, Investigation of deflector geometry and turbine aspect ratio effect on 3D modified in-pipe hydro Savonius turbine: Parametric study:, Renewable Energy 148(2020)44-59 Summary of the Invention [Problem to be solved by the invention]

[0004] When extracting energy by placing a turbine with a rotating axis perpendicular to the fluid flow direction inside a pipe, a turbine may be used that has an inner surface that receives the fluid flowing inside the pipe and has two arched blades with an orthogonal cross section perpendicular to the rotating axis.

[0005] Specifically, the two blades have a uniform thickness. Furthermore, in an orthogonal cross section perpendicular to the rotation axis, the inner peripheral surface of the blade is semicircular, the center of the inner peripheral surface is away from the rotation axis, and the rotation axis is disposed between both ends of the inner peripheral surface. Moreover, when viewed from the direction of the rotation axis, the two blades are disposed at equal intervals in the circumferential direction of the rotation axis.

[0006] The objective of the present disclosure is to extract more energy from a fluid flowing through a pipe compared to the case where energy is extracted using two arcuate blades of constant thickness and an inner circumferential surface with a semicircular cross section. [Means for solving the problem]

[0007] The turbine of the first aspect is characterized in that it is provided with a blade that is arranged inside a tube so as to be rotatable around a rotation axis perpendicular to the flow direction of a fluid flowing inside the tube, the blade having an arch-shaped orthogonal cross section perpendicular to the rotation axis, the inner surface of the blade being semicircular in the orthogonal cross section, the center of the inner surface being away from the rotation axis, the rotation axis being arranged between both ends of the inner surface, the turbine has three or more blades, and when viewed from the direction of the rotation axis, each of the blades is arranged at equal intervals in the circumferential direction of the rotation axis.

[0008] According to the above configuration, the fluid flowing inside the pipe toward the turbine presses against the inner circumferential surface of one of the blades and flows along the inner circumferential surface. Furthermore, the fluid flowing along the inner circumferential surface of one of the blades presses against the inner circumferential surfaces of the other blades and flows along the inner circumferential surfaces, and flows inside the pipe away from the turbine. Here, the three or more blades are arranged at equal intervals in the circumferential direction of the rotating shaft. Therefore, the fluid flowing toward the turbine presses against the inner circumferential surface of one of the blades.

[0009] As a result, the turbine can extract more energy from the fluid flowing through a tube than would be possible with two arcuate blades of constant thickness and semicircular inner periphery.

[0010] The turbine according to a second aspect is the turbine of the first aspect, characterized in that the thickness of the central portion of the blade in the orthogonal cross section is greater than the thickness of the end portion.

[0011] According to the above configuration, the thickness of the blade at the center in the orthogonal cross section is made larger than the thickness at the end, so that the amount of fluid passing between the blade and the inner wall of the tube and next to the turbine is smaller than if the blade had the same thickness at the center as at the end.

[0012] This allows the turbine to extract more energy than if the blade were as thick in the center as it is at the ends.

[0013] A governor device according to a third aspect is characterized in that it comprises a governor body that reduces the pressure of gas as a flowing fluid, the turbine described in claim 1 or 2 that is arranged upstream of the governor body in the flow direction of the gas and rotated by the flowing gas, and a conversion member that converts the rotation of the turbine into energy.

[0014] According to the above-mentioned configuration, the turbine is disposed upstream of the governor body in the gas flow direction, which makes it possible to extract energy from the energy that would otherwise be lost in the governor body and would not be utilized. Effect of the Invention

[0015] According to the present disclosure, more energy can be extracted from a fluid flowing through a pipe compared to the case where energy is extracted using two arcuate blades of constant thickness and having an inner circumferential surface with a semicircular cross section. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a configuration diagram showing a governor device according to a first embodiment of the present disclosure. [Diagram 2] 1 is a diagram showing a turbine according to a first embodiment of the present disclosure, disposed within a gas conduit; [Diagram 3] 1 is a cross-sectional view of a turbine according to a first embodiment of the present disclosure, taken horizontally through a central portion. [Figure 4]1A and 1B are a plan view and a side view, respectively, of a turbine according to a first embodiment of the present disclosure. [Diagram 5] FIG. 2 is a side view of the turbine according to the first embodiment of the present disclosure, taken from another side; [Figure 6] 3A and 3B are phase diagrams illustrating a rotating state of the turbine according to the first embodiment of the present disclosure. [Figure 7] 3A and 3B are phase diagrams illustrating a rotating state of the turbine according to the first embodiment of the present disclosure. [Figure 8] 1 is a graph showing evaluation results of the turbine according to the first embodiment of the present disclosure; [Figure 9] 1A and 1B are diagrams showing an evaluation model used to evaluate a turbine according to a first embodiment of the present disclosure. [Figure 10] FIG. 2 is a cross-sectional view of a central portion of a turbine according to a comparative embodiment of the present disclosure, cut in the horizontal direction. [Figure 11] 5A and 5B are phase diagrams showing a rotating state of a turbine according to a comparative embodiment to the turbine according to the first embodiment of the present disclosure. [Figure 12] 5A and 5B are phase diagrams showing a rotating state of a turbine according to a comparative embodiment to the turbine according to the first embodiment of the present disclosure. [Figure 13] 1A and 1B are diagrams showing an evaluation model used to evaluate a turbine according to a comparative embodiment of the turbine in accordance with the first embodiment of the present disclosure. [Figure 14] FIG. 11 is a cross-sectional view of a turbine according to a second embodiment of the present disclosure, taken horizontally through a central portion. [Figure 15] 6A and 6B are phase diagrams illustrating a rotating state of a turbine according to a second embodiment of the present disclosure. [Figure 16] 6A and 6B are phase diagrams illustrating a rotating state of a turbine according to a second embodiment of the present disclosure. [Figure 17]13A and 13B are diagrams showing an evaluation model used to evaluate a turbine according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] First Embodiment An example of a governor device and a turbine according to a first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 13. Note that arrow H shown in each figure indicates the up-down direction when the rotating shaft of the turbine is in the vertical direction, arrow D shown in each figure indicates the horizontal direction when the rotating shaft of the turbine is in the vertical direction and indicates the gas flow direction, and arrow W shown in each figure indicates the horizontal direction when the rotating shaft of the turbine is in the vertical direction and indicates the direction perpendicular to the gas flow direction.

[0018] (Gas Supply System 10) First, a description will be given of a gas supply system 10 in which the governor device 20 is used. The gas supply system 10 is an example of a fluid supply system.

[0019] The gas supply system 10 is, for example, a system that supplies city gas from a supply source (for example, a gas manufacturing plant) to consumers (for example, general homes, commercial facilities, industrial facilities, etc.) The gas supply system 10 includes a first gas pipe 11, a second gas pipe 12, and a governor device 20, as shown in FIG.

[0020] The direction in which gas flows is referred to as the gas flow direction in the gas supply system 10. Gas is an example of a fluid.

[0021] The first gas pipe 11 is disposed on the supply source side (i.e., the upstream side in the gas flow direction) of the second gas pipe 12 in the gas supply system 10. The first gas pipe 11 is a gas pipe for passing city gas having a higher gas pressure than that in the second gas pipe 12.

[0022] The second gas pipe 12 is disposed on the consumer side (i.e., downstream in the gas flow direction) of the first gas pipe 11 in the gas supply system 10. The second gas pipe 12 is a gas pipe for carrying city gas having a lower pressure than that in the first gas pipe 11.

[0023] [Governor device 20] The governor device 20 is disposed between the first gas pipe 11 and the second gas pipe 12 in the gas supply system 10. That is, in the gas supply system 10, the governor device 20 is disposed downstream of the first gas pipe 11 in the gas flow direction and upstream of the second gas pipe 12 in the gas flow direction.

[0024] The governor device 20 functions as a pressure regulator that regulates the pressure of the gas flowing from the first gas pipe 11 to the second gas pipe 12 between the first gas pipe 11 and the second gas pipe 12. Specifically, the governor device 20 reduces the pressure of the gas from the first gas pipe 11 and sends it to the second gas pipe 12.

[0025] The governor device 20 has a basic component 26 including the gas pipe 22 and the governor body 24, and a housing 28. The basic component 26 including the gas pipe 22 and the governor body 24 is housed inside the housing 28. The gas pipe 22 is an example of a pipe.

[0026] The basic component 26 is a component for allowing gas to flow, and includes the gas pipe 22, the governor body 24, and other components such as other gas pipes and valves. In the basic component 26, gas flows from an inlet 25 to which the first gas pipe 11 is connected to an outlet 27 to which the second gas pipe 12 is connected (see arrows 20A, 20B, 20C, and 20D).

[0027] The governor body 24 is a component that reduces the pressure of the gas flowing in the basic component 26. The gas pipe 22 is provided on the upstream side of the governor body 24 in the gas flow direction. Specifically, the gas pipe 22 is connected to the governor body 24 on the upstream side of the gas flow direction. The flow path diameter of the gas pipe 22 is smaller than the flow path diameter of the components connected to the gas pipe 22 on the upstream side of the flow direction and the flow path diameter of the components connected to the gas pipe 22 on the downstream side of the flow direction (specifically, the governor body 24). In addition, a turbine 50 is disposed in the gas pipe 22. The governor device 20 includes a generator 36 as a conversion member that converts the rotation of the turbine 50 into energy.

[0028] In the governor device 20, as described below, a turbine 50 is disposed relative to the gas pipe 22. The gas flowing through the governor device 20 is depressurized by the turbine 50, and is further depressurized by the governor body 24. Therefore, in the governor device 20, the gas in the flow passages indicated by the arrows 20A and 20B, the gas in the flow passage indicated by the arrow 20C, and the gas in the flow passage indicated by the arrow 20D become gradually lower in pressure in this order.

[0029] (Configuration of turbine 50) The turbine 50 is a prime mover that converts the energy of the gas flowing in the governor device 20 into rotational force and extracts the energy. The turbine 50 is disposed in the gas pipe 22 as shown in FIG.

[0030] 2 and 3, the turbine 50 has a first blade 52, a second blade 54, a third blade 56, a first spacer 58, a second spacer 60, and a rotating shaft member 62. In the following description, the first blade 52, the second blade 54, and the third blade 56 may be referred to as the "first, second, and third blades 52, 54, 56," and the first spacer 58 and the second spacer 60 may be referred to as the "first and second spacers 58, 60."

[0031] The turbine 50 is a vertical-axis turbine, and its rotation axis extends in a direction (arrow H) perpendicular to the flow direction (arrow D) of gas in the gas pipe 22. The first, second and third blades 52, 54, 56 and the first and second spacers 58, 60 are disposed inside the gas pipe 22 by a rotating shaft member 62 so as to be rotatable around the rotation axis.

[0032] [Rotary shaft member 62] 2, the rotating shaft member 62 extends in a direction (arrow H) perpendicular to the gas flow direction (arrow D) of the gas pipe 22, and protrudes upward from the inside of the gas pipe 22 through a through hole (not shown) provided in the gas pipe 22. In other words, the rotation axis (CA in the figure) of the rotating shaft member 62 extends in a direction (arrow H) perpendicular to the gas flow direction of the gas pipe 22, and passes through the center of the gas pipe 22, which has a circular cross section.

[0033] [First spacer 58, second spacer 60] 2, the first spacer 58 and the second spacer 60 are disposed so as to sandwich the first, second, and third blades 52, 54, and 56 from above and below. The surfaces of the first and second spacers 58, 60 facing the inner wall 22a of the gas pipe 22 are spherical, and gaps are provided between the first and second spacers 58, 60 and the inner wall 22a of the gas pipe 22.

[0034] [First blade 52, second blade 54, third blade 56] The first blade 52, the second blade 54, and the third blade 56 have the same shape. In addition, the first, second, and third blades 52, 54, 56 are arranged at equal intervals in the circumferential direction of the rotation axis CA.

[0035] -First Blade 52- As shown in Fig. 3, the cross section of the first blade 52 perpendicular to the rotation axis CA is arch-shaped, and has a concave inner circumferential surface 52a that receives the flowing gas, and a convex outer circumferential surface 52b. In the cross section perpendicular to the rotation axis CA, the inner circumferential surface 52a and the outer circumferential surface 52b are semicircular, and the center (C01 in the figure) of the semicircular inner circumferential surface overlaps with the center of the semicircular outer circumferential surface 52b. As a result, the distance between the inner circumferential surface 52a and the outer circumferential surface 52b of the first blade 52 is the same. In other words, the thickness of the first blade 52 is the same.

[0036] Here, in the first embodiment, the term "semicircular" does not necessarily mean a perfect semicircle, and includes a semicircular shape including a straight portion (U-shape), and further includes an elliptical shape and a flat shape.

[0037] Furthermore, the center (C01 in the drawing) of the semicircular inner circumferential surface 52a is separated from the rotation axis (CA in the drawing) of the turbine 50, and the rotation axis CA is disposed between one end 521 of the inner circumferential surface 52a separated from the rotation axis CA and the other end 522 close to the rotation axis CA. In other words, the rotation axis CA is disposed on a line segment connecting one end 521 and the other end 522 of the inner circumferential surface 52a.

[0038] Moreover, the distance from one end 521 to the other end 522 of the inner circumferential surface 52a is defined as L1, and the distance from the rotation axis CA to the other end 522 is defined as L2. In this case, the ratio between the distance L1 and the distance L2 is the same regardless of the position in the cross section perpendicular to the rotation axis CA. In other words, the ratio between the distance L1 and the distance L2 is the same whether the cross section is in the vertical center of the first blade 52, in a cross section close to the first spacer 58, or in a cross section close to the second spacer 60.

[0039] -Second blade 54, third blade 56- Regarding the cross sections of the second blade 54 and the third blade 56 perpendicular to the rotation axis CA, differences from the cross section of the first blade 52 will be mainly described.

[0040] 3, the cross-sectional shape of the second blade 54 is similar to that of the first blade 52. Specifically, when the first blade 52 is rotated 120 degrees counterclockwise about the rotation axis CA, the second blade 54 overlaps with the first blade 52.

[0041] 3, the cross-sectional shape of the third blade 56 is similar to that of the first blade 52. Specifically, when the first blade 52 is rotated 240 degrees counterclockwise about the rotation axis CA, the third blade 56 overlaps with the first blade 52.

[0042] 4(A)(B) and 5, the first, second and third blades 52, 54, 56 are disposed with the same gap between them and the inner wall 22a of the gas pipe 22. In other words, the first, second and third blades 52, 54, 56 are disposed with the same gap between them and the inner wall 22a of the gas pipe 22, whether it is a cross section of the vertical center of the first, second and third blades 52, 54, 56, a portion close to the first spacer 58, or a portion close to the second spacer 60.

[0043] (Function of Turbine 50) Next, the operation of the turbine 50 will be described in comparison with a turbine 350 according to a comparative embodiment. First, the configuration of the turbine 350 will be described, focusing mainly on the parts that differ from the turbine 50 according to the first embodiment.

[0044] [Configuration of turbine 350] 10, the turbine 350 includes a first blade 352 and a second blade 354. The first blade 352 and the second blade 354 have the same shape.

[0045] 10, a cross section of the first blade 352 perpendicular to the rotation axis CA is arched, and has a similar shape to the first blade 52 (see FIG. 3) of the turbine 50 according to the first embodiment. As a result, the first blade 352 has a concave inner circumferential surface 352a and a convex outer circumferential surface 352b.

[0046] 10, the cross-sectional shape of the second blade 54 is similar to that of the first blade 352. Specifically, when the first blade 352 is rotated 180 degrees counterclockwise about the rotation axis CA, the second blade 54 overlaps with the second blade 354.

[0047] [Function of turbines 50 and 350] 6(A), gas flowing toward the turbine 50 presses against the concave inner circumferential surface 52a and flows along the inner circumferential surface 52a. Furthermore, the gas flowing along the inner circumferential surface 52a presses against the inner circumferential surface 54a of the second blade 54 and the inner circumferential surface 56a of the third blade 56, and flows along the inner circumferential surfaces 54a, 56a, and flows inside the gas pipe 22 so as to move away from the turbine 50.

[0048] In this manner, the inner circumferential surfaces 52a, 54a, 56a are pressed by the gas flowing inside the gas pipe 22, causing the first, second, and third blades 52, 54, 56 to rotate clockwise about the rotation axis CA.

[0049] As shown in FIG. 6(B) and FIG. 7(A)(B), as the first, second, and third blades 52, 54, and 56 rotate, the gas flowing toward the turbine 50 presses against the concave inner circumferential surface 54a and flows along the inner circumferential surface 54a. Furthermore, the gas flowing along the inner circumferential surface 54a presses against the inner circumferential surface 56a and the inner circumferential surface 52a and flows along the inner circumferential surface 56a and the inner circumferential surface 52a, and flows inside the gas pipe 22 away from the turbine 50. Furthermore, the gas flowing toward the turbine 50 presses against the concave inner circumferential surface 56a and flows along the inner circumferential surface 56a. Furthermore, the gas flowing along the inner circumferential surface 56a presses against the inner circumferential surface 52a and the inner circumferential surface 54a and flows along the inner circumferential surface 52a and the inner circumferential surface 54a, and flows inside the gas pipe 22 away from the turbine 50. By repeating this, the first, second and third blades 52, 54 and 56 continue to rotate.

[0050] 11(A), the gas flowing toward the turbine 350 presses against the concave inner circumferential surface 352a and flows along the inner circumferential surface 352a. Furthermore, the gas flowing along the inner circumferential surface 352a presses against the inner circumferential surface 354a of the second blade 354 and flows along the inner circumferential surface 354a, and flows inside the gas pipe 22 so as to move away from the turbine 350.

[0051] 11(B) and 12(A)(B), as the first and second blades 352, 354 rotate, the gas flowing toward the turbine 350 presses against the concave inner circumferential surface 354a and flows along the inner circumferential surface 354a. Furthermore, the gas flowing along the inner circumferential surface 354a presses against the inner circumferential surface 352a and flows along the inner circumferential surface 352a, and flows inside the gas pipe 22 so as to move away from the turbine 50. By repeating this, the first and second blades 352, 354 continue to rotate.

[0052] Here, in the turbine 350 according to the comparative embodiment, when the first and second blades 352, 354 are in the rotational position shown in FIG. 12(A), the gas flowing toward the turbine 350 does not press against the inner circumferential surfaces 352a, 354a, but flows inside the gas pipe 22, passing between the first and second blades 352, 354 and the inner wall 22a of the gas pipe 22, and away from the turbine 350.

[0053] On the other hand, in the turbine 50 according to the first embodiment, since there are three blades, as shown in Figures 6(A)(B) and 7(A)(B), gas flowing toward the turbine 50 presses against any of the inner circumferential surfaces 52a, 54a, 56a at any rotational position of the first, second, and third blades 52, 54, 56. As a result, in the turbine 50 according to the first embodiment, pressure is more effectively exerted by the gas flowing toward the turbine 50 than in the turbine 350 according to the comparative embodiment.

[0054] 〔evaluation〕 Next, a comparative experiment in which the performance of the turbine 50 according to the first embodiment and the performance of the turbine 350 according to a comparative embodiment are compared will be described.

[0055] 1. Evaluation specifications As an evaluation model 70 of the turbine 50, one having a constant thickness in the rotation axis direction and a constant cross-sectional shape and having a base 72, as shown in Figs. 9(A) and 9(B), was used.

[0056] As shown in FIGS. 13(A) and 13(B), an evaluation model 370 of the turbine 350 had a constant thickness in the axial direction and a constant cross-sectional shape, and included a base 372, similar to the turbine 50.

[0057] 2. Evaluation Method 9(B) and 13(B), the evaluation models 70, 370 were rotatably placed inside a pipe 74 having a rectangular cross section, and water was run through the inside of the pipe 74 to rotate the evaluation models 70, 370. Note that with the exception of the cross-sectional shape of the evaluation models 70, 370, all items were the same between the evaluation of the evaluation models 70 and the evaluation model 370.

[0058] 3. Evaluation items The relationship between tip speed ratio λ and power coefficient Cp was calculated for each specification and plotted on a graph. Here, power coefficient Cp is the efficiency of converting the energy of the flowing fluid into mechanical power by the turbine, and tip speed ratio λ is the ratio of the turbine tip speed to the fluid flow velocity.

[0059] 4. Evaluation Results The relationship between the circumferential speed ratio λ and the power coefficient Cp is shown in the graph of Fig. 8. The horizontal axis is the circumferential speed ratio λ, and the vertical axis is the power coefficient Cp. In addition, "◯" in the graph indicates the evaluation result of evaluation model 370, and "▲" in the graph indicates the evaluation result of evaluation model 70.

[0060] From this evaluation result, it is seen that, for the power coefficient Cp, the evaluation result of the evaluation model 70 is superior to the evaluation result of the evaluation model 370 at any tip speed ratio λ. In other words, it is seen that, for the power coefficient Cp, the turbine 50 is superior to the turbine 350 at any tip speed ratio λ.

[0061] (summary) As described above, in the turbine 50, by having three blades, the power coefficient Cp of the turbine 50 is greater than the power coefficient Cp of the comparative turbine 350. In other words, by having three blades, the turbine 50 can extract more energy from the flowing fluid than the comparative turbine 350.

[0062] In the governor device 20, the turbine 50 is disposed upstream of the governor body 24 that reduces the pressure of the gas. This allows the turbine 50 to extract energy from the energy that would otherwise be lost in the governor body 24 and would not be utilized.

[0063] <Second embodiment> An example of a governor device and a turbine according to a second embodiment of the present disclosure will be described with reference to Fig. 14 to Fig. 17. Note that, regarding the governor device and the turbine according to the second embodiment, differences from the first embodiment will be mainly described.

[0064] (Configuration of turbine 150) 14, the turbine 150 according to the second embodiment has a first blade 152, a second blade 154, and a third blade 156. In the following description, the first blade 152, the second blade 154, and the third blade 156 may be referred to as "first, second, and third blades 152, 154, 156."

[0065] [First blade 152, second blade 154, third blade 156] The first blade 152, the second blade 154, and the third blade 156 have the same shape. Furthermore, the first, second, and third blades 152, 154, and 156 are disposed at equal intervals in the circumferential direction of the rotation axis CA.

[0066] -First Blade 152- 14, the cross section of first blade 152 perpendicular to rotation axis CA is arch-shaped, and has a concave inner circumferential surface 152a and a convex outer circumferential surface 152b with respect to a line segment connecting both ends of first blade 52. In the cross section perpendicular to rotation axis CA, this inner circumferential surface 152a is semicircular, and has the same shape as inner circumferential surface 52a of first blade 52 according to the first embodiment.

[0067] Moreover, the outer peripheral surface 152b is convex so that the distance between the inner peripheral surface 152a and the outer peripheral surface 152b at the center of the inner peripheral surface 152a is larger than the distance between the inner peripheral surface 152a and the outer peripheral surface 152b at the end of the inner peripheral surface 152a. In other words, the outer peripheral surface 152b is convex so that the thickness at the center of the first blade 152 is larger than the thickness at the end. In this embodiment, the "thickness" refers to the distance between the inner peripheral surface 152a and the outer peripheral surface 152b.

[0068] Specifically, the outer peripheral surface 152b includes a trajectory surface 624 that overlaps with the rotation trajectory at one end 621 of the outer peripheral surface 152b that is distant from the rotation axis CA, and an extension surface 626 that extends from the other end 622 of the outer peripheral surface 152b close to the rotation axis CA to an end of the trajectory surface 624. More specifically, the trajectory surface 624 overlaps with 1 / 4 of the rotation trajectory at the one end 621, and is formed into a 1 / 4 spherical shape. In this way, the trajectory surface 624 overlaps with the rotation trajectory at the one end 621 in any cross section in the direction of the rotation axis CA. In other words, the trajectory surface 624 overlaps with the rotation trajectory of the turbine 150 in any cross section in the direction of the rotation axis CA. The rotation trajectory at the one end 621 of the outer peripheral surface 152b that is distant from the rotation axis CA is the same as the rotation trajectory of the turbine 150.

[0069] -Second blade 154, third blade 156- Regarding the cross sections of second blade 154 and third blade 156 perpendicular to rotation axis CA, differences from the cross section of first blade 152 will be mainly described.

[0070] 14, the cross-sectional shape of the second blade 154 is similar to that of the first blade 152. Specifically, when the first blade 152 is rotated 120 degrees counterclockwise about the rotation axis CA, the second blade 154 overlaps with the first blade 152.

[0071] 14, the cross-sectional shape of third blade 156 is similar to that of first blade 152. Specifically, when first blade 152 is rotated 240 degrees counterclockwise about rotation axis CA, it overlaps with third blade 156.

[0072] (Function of Turbine 150) In the turbine 150, with the concave inner circumferential surface 152a of the first blade 152 facing the upstream side of the gas flow direction (arrow D) as shown in Fig. 15(A), the gas flowing toward the turbine 150 presses against the concave inner circumferential surface 152a and flows along the inner circumferential surface 152a. Furthermore, the gas flowing along the inner circumferential surface 152a presses against the inner circumferential surface 154a of the second blade 154 and the inner circumferential surface 156a of the third blade 156 and flows along the inner circumferential surfaces 154a, 156a, and flows inside the gas pipe 22 so as to move away from the turbine 150.

[0073] In this manner, the inner circumferential surfaces 152a, 154a, 156a are pressed by the gas flowing inside the gas pipe 22, causing the first, second, and third blades 152, 154, 156 to rotate clockwise about the rotation axis CA.

[0074] 15(B) and 16(A)(B), as the first, second, and third blades 152, 154, and 156 rotate, the gas flowing toward the turbine 150 presses against the concave inner circumferential surface 154a and flows along the inner circumferential surface 154a. Furthermore, the gas flowing along the inner circumferential surface 154a presses against the inner circumferential surface 156a and the inner circumferential surface 152a and flows along the inner circumferential surface 156a and the inner circumferential surface 152a, and flows inside the gas pipe 22 away from the turbine 150. Moreover, the gas flowing toward the turbine 150 presses against the concave inner circumferential surface 156a and flows along the inner circumferential surface 156a. Furthermore, the gas flowing along the inner circumferential surface 156a presses against the inner circumferential surfaces 152a and 154a, and flows along the inner circumferential surfaces 152a and 154a, flowing inside the gas pipe 22 away from the turbine 150. By repeating this process, the first, second, and third blades 152, 154, and 156 continue to rotate.

[0075] Here, in the turbine 150 according to the second embodiment, the outer peripheral surfaces 152b, 154b, 156b of the first, second, and third blades 152, 154, and 156 are convex so that the thickness at the center of the first, second, and third blades 152, 154, and 156 is thicker than the thickness at the end. For this reason, as shown in Figures 15(A)(B) and 16(A)(B), at any rotational position of the first, second, and third blades 152, 154, and 156, the gas flowing toward the turbine 150 is suppressed from flowing through the inside of the gas pipe 22 between the inner wall 22a of the gas pipe 22 and the tips of the first, second, and third blades 152, 154, and 156 and away from the turbine 150. As a result, the gas flowing toward the turbine 150 presses against any of the inner peripheral surfaces 152a, 154a, and 156a. Therefore, in the turbine 150 according to the second embodiment, pressure is applied more effectively by the gas flowing toward the turbine 150 than in the turbine 350 according to the comparative embodiment.

[0076] 〔evaluation〕 Next, an experiment for evaluating the performance of the turbine 150 according to the second embodiment will be described.

[0077] 1. Evaluation specifications As an evaluation model 170 of the turbine 150, as shown in Figs. 17(A) and 17(B), a model having a constant thickness in the axial direction and a constant cross-sectional shape and having a base 172 was used.

[0078] 2. Evaluation results The relationship between the peripheral speed ratio λ and the power coefficient Cp is shown in the graph of Fig. 8. The horizontal axis is the peripheral speed ratio λ, and the vertical axis is the power coefficient Cp. In addition, "△" in the graph indicates the evaluation result of the evaluation model 170.

[0079] From this evaluation result, it is seen that, for the power coefficient Cp, at any tip speed ratio λ, the evaluation result of the evaluation model 170 is superior to the evaluation results of the above-mentioned evaluation models 70 and 370. In other words, it is seen that, for the power coefficient Cp, at any tip speed ratio λ, the turbine 150 is superior to the turbine 50 and the turbine 350.

[0080] (summary) As described above, the outer peripheral surfaces 152b, 154b, 156b of the first, second, and third blades 152, 154, and 156 of the turbine 150 are convex so that the thicknesses of the first, second, and third blades 152, 154, and 156 at the center are thicker than the thicknesses of the ends. This makes the power coefficient Cp of the turbine 150 higher than the power coefficients Cp of the turbine 50 and the turbine 350 according to the comparative embodiment. In other words, the turbine 150 can extract more energy from the flowing fluid than the turbine 50 and the turbine 350 according to the comparative embodiment by making the outer peripheral surfaces 152b, 154b, and 156b of the first, second, and third blades 152, 154, and 156 convex so that the thicknesses of the first, second, and third blades 152, 154, and 156 at the center are thicker than the thicknesses of the ends.

[0081] Although the present disclosure has been described in detail with respect to a specific embodiment, it is clear to those skilled in the art that the present disclosure is not limited to the embodiment, and that various other embodiments are possible within the scope of the present disclosure. Modifications, deletions, additions, and combinations of the embodiments are possible as long as they do not violate the technical ideas that a person skilled in the art can recognize from the claims, the specification, and the drawings.

[0082] Furthermore, in the above-described embodiment, the turbines 50 and 150 have three blades, but the number of blades may be four or more.

[0083] In addition, in the above embodiment, the first, second and third blades 52, 54, 56 and the first, second and third blades 152, 154, 156 are solid, but they may be hollow.

[0084] In the second embodiment, the trajectory surface 624 of the outer peripheral surfaces 152b, 154b, 156b overlaps with the trajectory of the turbine in the cross section, but the overlap amount is not limited to 1 / 4 of the trajectory of the turbine 150. In other words, it is sufficient that at least a part of the outer peripheral surfaces 152b, 154b, 156b of the first, second, and third blades 152, 154, 156 has a trajectory surface that overlaps with the trajectory of the turbine. This suppresses the passage of gas between the first, second, and third blades 152, 154, 156 of the rotating turbine and the inner wall 22a, so that the gas effectively presses the inner peripheral surfaces 152a, 154a, 156a of the first, second, and third blades 152, 154, 156 that rotate. [Explanation of symbols]

[0085] 20 Governor device 22 Gas Pipe 22a Inner wall 24 Governor body 36 Generator (an example of a conversion component) 50 Turbine 52 First Blade 52a Inner surface 54 Second Blade 54a Inner surface 56 Third Blade 56a Inner surface 62 Rotating shaft member 150 Turbine 152 First Blade 152a Inner surface 154 Second Blade 154a Inner surface 156 Third Blade 156a Inner surface 624 Trajectory plane CA Rotation Axis

Claims

1. a blade disposed inside the pipe so as to be rotatable about a rotation axis perpendicular to a flow direction of a fluid flowing inside the pipe, the blade having an arch-shaped cross section perpendicular to the rotation axis; In the orthogonal cross section, the inner peripheral surface of the blade is semicircular, the center of the inner peripheral surface is away from the rotation axis, and the rotation axis is disposed between both ends of the inner peripheral surface, and the number of the blades is three or more, and each of the blades is disposed at equal intervals in the circumferential direction of the rotation axis as viewed from the direction of the rotation axis. Turbine.

2. The thickness of the central portion of the blade in the orthogonal cross section is made thicker than the thickness of the end portion. The turbine of claim 1 .

3. A governor body that reduces the pressure of gas as a flowing fluid; The turbine according to claim 1 or 2, which is disposed upstream of the governor body in a gas flow direction and rotated by the flowing gas; A conversion member that converts the rotation of the turbine into energy; A governor device comprising:

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