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 a plurality of 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, the rotational axis is arranged between both ends of the inner peripheral surface, and when viewed from a direction of the rotational axis, the blades are arranged at equal intervals in a circumferential direction of the rotational axis, and a thickness of a central part of the blade in the orthogonal cross section is made thicker than a thickness of end parts.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 having an inner circumferential surface with a semicircular cross section. [Means for solving the problem]

[0007] The turbine according to a first aspect is characterized in that it comprises a plurality of blades arranged inside a pipe so as to be rotatable around a rotation axis perpendicular to the flow direction of a fluid flowing inside the pipe, the blades having an arch-shaped orthogonal cross section perpendicular to the rotation axis, the inner surfaces of the blades being semicircular in the orthogonal cross section, the center of the inner surfaces being away from the rotation axis and the rotation axis being arranged between both ends of the inner surfaces, and when viewed from the direction of the rotation axis, the blades are arranged at equal intervals in the circumferential direction of the rotation axis, and the thickness of the central part of the blades in the orthogonal cross section is thicker than the thickness of the ends.

[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 outer circumferential surface of the blade is convex so that the thickness of the blade at the center is greater than the thickness of the blade at the end. Therefore, compared to the case where a blade with a constant thickness is used, less fluid flows beside the turbine through between the blade and the inner wall of the pipe, and more fluid presses against the inner circumferential surface of the blade.

[0009] As a result, more energy can be extracted from the fluid flowing through a pipe than when two blades with a constant thickness and an arcuate cross-section having a semicircular inner periphery are used to extract energy from the fluid flowing through a pipe.

[0010] The turbine according to a second aspect is the turbine of the first aspect, characterized in that the turbine includes three of the blades.

[0011] According to the above configuration, since the rotor has three blades, the fluid flowing inside the tube presses against the inner circumferential surface of one of the blades at any rotational position, so that the rotor can extract more energy than the rotor with two blades.

[0012] 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.

[0013] 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

[0014] 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]

[0015] [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

[0016] 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.

[0017] (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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] [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.

[0023] 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.

[0024] 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.

[0025] 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).

[0026] 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.

[0027] 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.

[0028] (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.

[0029] 2 and 3, the turbine 50 has a first blade 52, a second blade 54, a first spacer 58, a second spacer 60, and a rotating shaft member 62. In the following description, the first blade 52 and the second blade 54 may be referred to as the "first and second blades 52, 54," and the first spacer 58 and the second spacer 60 may be referred to as the "first and second spacers 58, 60."

[0030] 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 and second blades 52, 54 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.

[0031] [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 this rotating shaft member 62 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.

[0032] [First spacer 58, second spacer 60] 2, the first spacer 58 and the second spacer 60 are disposed so as to sandwich the first and second blades 52, 54 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 a gap is provided between the first and second spacers 58, 60 and the inner wall 22a of the gas pipe 22.

[0033] [First blade 52, second blade 54] The first blade 52 and the second blade 54 have the same shape. In addition, the first and second blades 52, 54 are disposed with the same gap between them and the inner wall 22a of the gas pipe 22.

[0034] -First Blade 52- 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 is semicircular.

[0035] 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.

[0036] 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.

[0037] Furthermore, 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 of 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 at the center of the first and second blades 52 and 54 in the vertical direction, at a cross section close to the first spacer 58, or at a cross section close to the second spacer 60.

[0038] Moreover, the outer peripheral surface 52b is convex with respect to the line segment connecting both ends of the first blade 52 so that the distance between the inner peripheral surface 52a and the outer peripheral surface 52b at the center of the inner peripheral surface 52a is larger than the distance between the inner peripheral surface 52a and the outer peripheral surface 52b at the ends of the inner peripheral surface 52a. In other words, the outer peripheral surface 52b is convex with respect to the line segment connecting both ends of the first blade 52 so that the thickness at the center of the first blade 52 is thicker than the thickness at the ends. In this embodiment, the "thickness" refers to the distance between the inner peripheral surface 52a and the outer peripheral surface 52b.

[0039] Specifically, the outer peripheral surface 52b includes a trajectory surface 624 that overlaps with the rotation trajectory at one end 621 of the outer peripheral surface 52b 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 52b 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 50 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 52b that is distant from the rotation axis CA is the same as the rotation trajectory of the turbine 50.

[0040] -Second Blade 54- Regarding the cross section of the second blade 54 perpendicular to the rotation axis CA, the following mainly describes the differences from the cross section of the first blade 52. As shown in Fig. 3, the cross-sectional shape of the second blade 54 is similar to the cross-sectional shape of the first blade 52. Specifically, when the first blade 52 is rotated 180 degrees counterclockwise about the rotation axis CA, it overlaps with the second blade 54.

[0041] 4(A)(B) and 5, the first and second blades 52, 54 are disposed with the same gap between them and the inner wall 22a of the gas pipe 22. In other words, the first and second blades 52, 54 are disposed with the same gap between them and the inner wall 22a of the gas pipe 22, whether in the cross section of the vertical center of the first and second blades 52, 54, in the portion close to the first spacer 58, or in the portion close to the second spacer 60.

[0042] (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 according to the comparative embodiment will be described, focusing mainly on the differences from the turbine 50 according to the first embodiment.

[0043] [Configuration of turbine 350] 10, a turbine 350 according to the comparative embodiment includes a first blade 352 and a second blade 354. The first blade 352 and the second blade 354 have the same shape.

[0044] As shown in Fig. 10, the cross section of the first blade 352 perpendicular to the rotation axis CA is arched, and has a concave inner circumferential surface 352a and a convex outer circumferential surface 352b that receive the flowing gas. In the cross section perpendicular to the rotation axis CA, the inner circumferential surface 352a and the outer circumferential surface 352b 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 352b. In other words, the first blade 352 has a constant thickness. The shape of the inner circumferential surface 352a of the first blade 352 is the same as the shape of the inner circumferential surface 52a of the first blade 52 of the first embodiment.

[0045] The second blade 354 overlaps with the first blade 352 when the first blade 352 is rotated 180 degrees counterclockwise about the rotation axis CA.

[0046] [Function of turbines 50 and 350] 6(A), the 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 flows along the inner circumferential surface 54a, and flows inside the gas pipe 22 so as to move away from the turbine 50.

[0047] In this manner, the inner circumferential surfaces 52a, 54a are pressed by the gas flowing inside the gas pipe 22, causing the first and second blades 52, 54 to rotate clockwise about the rotation axis CA.

[0048] 6(B) and 7(A)(B), as the first and second blades 52, 54 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 52a and flows along the inner circumferential surface 52a, and flows inside the gas pipe 22 away from the turbine 50. By repeating this process, the first and second blades 52, 54 continue to rotate.

[0049] 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.

[0050] 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.

[0051] 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 so as to pass between the first and second blades 352, 354 and the inner wall 22a of the gas pipe 22 (to the side of the turbine 350) and move away from the turbine 350.

[0052] On the other hand, in the turbine 50 according to the first embodiment, the outer peripheral surfaces 52b, 54b of the first and second blades 52, 54 are convex so that the thickness at the center of the first and second blades 52, 54 is thicker than the thickness at the end. Therefore, as shown in FIG. 7A, the amount of gas passing between the first and second blades 52, 54 and the inner wall 22a of the gas pipe 22 is small, and the gas that flows hits the extension surface 626 of the outer peripheral surface 52b of the first blade 52 and flows along the extension surface 626. The gas that flows along the extension surface 626 presses against the inner peripheral surface 54a of the second blade 54 and flows along the inner peripheral surface 54a, and flows inside the gas pipe 22 so as to move away from the turbine 50.

[0053] As a result, in the turbine 50 according to the first embodiment, pressure is applied more effectively 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

[0056] 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.

[0057] Moreover, an evaluation model 370 of the turbine 350 used had a constant thickness in the rotation axis direction and a constant cross-sectional shape, and had a base 372, similar to the turbine 50 in FIGS.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] (summary) As described above, the outer peripheral surfaces 52b, 54b of the turbine 50 are convex so that the thickness of the first and second blades 52, 54 at the center is greater than the thickness of their ends. This makes the power coefficient Cp of the turbine 50 higher than the power coefficient Cp of the turbine 350 of the comparative embodiment. In other words, by making the outer peripheral surfaces 52b, 54b convex so that the thickness of the first and second blades 52, 54 at the center is greater than the thickness of their ends, the turbine 50 can extract more energy from the flowing gas than the turbine 350 of the comparative embodiment.

[0063] 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.

[0064] <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.

[0065] (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."

[0066] [First blade 152, second blade 154, third blade 156] The first, second and third blades 152, 154 and 156 have a shape similar to that of the first blade 52 of the first embodiment.

[0067] Specifically, when the first blade 152 is rotated 120 degrees counterclockwise about the rotation axis CA, the first blade 152 overlaps with the second blade 154. When the first blade 152 is rotated 240 degrees counterclockwise about the rotation axis CA, the first blade 152 overlaps with the third blade 156.

[0068] (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.

[0069] 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.

[0070] 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.

[0071] Here, in the turbine 150 according to the second embodiment, since there are three blades, as shown in Figures 15(A)(B) and 16(A)(B), gas flowing toward the turbine 150 presses against any of the inner circumferential surfaces 152a, 154a, 156a at any rotational position of the first, second, and third blades 152, 154, and 156. As a result, in the turbine 50 according to the second embodiment, pressure is more effectively exerted by the gas flowing toward the turbine 150 than in the turbine 350 according to the comparative embodiment.

[0072] 〔evaluation〕 Next, an experiment for evaluating the performance of the turbine 150 according to the second embodiment will be described.

[0073] 1. Evaluation specifications As an evaluation model 170 of the turbine 150, one having a constant thickness in the rotation axis direction and a constant cross-sectional shape and having a base 172, as shown in Figs. 17(A) and (B), was used.

[0074] 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.

[0075] 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 result of the above-mentioned evaluation model 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 350.

[0076] (summary) As described above, the turbine 150 has three blades, and therefore, regardless of the rotational positions of the first, second, and third blades 152, 154, and 156, the gas flowing toward the turbine 150 presses against any of the inner circumferential surfaces 152a, 154a, and 156a. As a result, the power coefficient Cp of the turbine 150 is greater than the power coefficient Cp of the turbine 350 according to the comparative embodiment. In other words, the turbine 150 has three blades, and therefore can extract more energy from the flowing fluid than the turbine 350 according to the comparative embodiment.

[0077] 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.

[0078] Furthermore, in the second embodiment, the turbine 150 has three blades, but the number of blades may be four or more. Furthermore, in the second embodiment, the first, second and third blades 152, 154 and 156 are solid, but they may be hollow.

[0079] In the first embodiment, the trajectory surface 624 of the outer peripheral surfaces 52b, 54b 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 50. In other words, it is sufficient that at least a part of the outer peripheral surfaces 52b, 54b of the first and second blades 52, 54 has a trajectory surface that overlaps with the trajectory of the turbine. This prevents gas from passing between the first and second blades 52, 54 of the rotating turbine and the inner wall 22a, so that the gas effectively presses the inner peripheral surfaces 52a, 54a of the first and second blades 52, 54 around which the gas rotates. [Explanation of symbols]

[0080] 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 62 Rotating shaft member 74 tube 150 Turbine 152 First Blade 152a Inner surface 154 Second Blade 154a Inner surface 156 Third Blade 156a Inner surface CA Rotation Axis

Claims

1. a plurality of blades arranged 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 blades 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 when viewed from the direction of the rotation axis, each of the blades is disposed at equal intervals in the circumferential direction of the rotation axis, and the thickness of the central portion of the blade in the orthogonal cross section is made thicker than the thickness of the end portion. Turbine.

2. The blade includes three blades. 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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