JP2021004585A - Rotor blade for two-phase flow turbine and two-phase flow turbine including the rotor blade - Google Patents

Abstract

To provide a rotor blade for a two-phase flow turbine capable of improving efficiency of the two-phase flow turbine and the two-phase flow turbine including the rotor blade.SOLUTION: A rotor blade for a two-phase flow turbine driven by a gas-liquid two-phase flow of fluid includes: a rotating shaft provided rotatably; a disk-shaped disk fixed to the rotating shaft; a plurality of blades provided in a hub on the outer peripheral surface of the disk to be spaced from each other in a circumferential direction around the rotating shaft; and shroud parts each facing a tip end of each of the plurality of blades. The shroud part is configured so that a radius of an inner peripheral surface of the shroud part from a rotating axis center of the rotating shaft reduces from an inlet end toward an outlet end of the shroud part. Each of the plurality of blades is configured so that a radius of the tip end of the blade from the rotating axis center reduces from a front edge of the blade toward a rear edge of the blade.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to moving blades of a two-phase flow turbine and a two-phase flow turbine including the moving blades.

Patent Documents 1 and 2, respectively, describe a two-phase flow turbine in which a gas-liquid two-phase flow drives a turbine to recover power. Generally, for two-phase flow turbines, the type of axial flow impulse turbine is used. In such a two-phase flow turbine, the gas-liquid two-phase flow flowing out of one or more nozzles is in the direction of rotation of the turbine rotor while flowing through a flow path formed between adjacent blades of the turbine rotor. Give power to the wings. The force applied to the blades causes the turbine rotor to rotate, generating rotational power.

Such a two-phase flow turbine includes a nozzle that generates a gas-liquid two-phase flow and a rotor blade that includes a turbine rotor that is rotated by the gas-liquid two-phase flow that flows out of the nozzle. Turbine rotors have a disc fixed to a rotating shaft and multiple blades fixed to the disc, and the blades often have shrouds on the tip ends of the blades from the blades by centrifugal force. The gas-liquid two-phase flow is prevented from being released to the outside.

Japanese Patent No. 3222350 Judgment No. 60-187105

FIG. 15 shows a view of the conventional two-phase flow turbine 200 as viewed from the axial direction of the rotating shaft 206. Here, the Cartesian coordinates in the stationary system are set, the horizontal direction in FIG. 15 is the X axis, the right direction is positive, the direction perpendicular to the X axis is the Y axis, the upward direction is positive, the center of the rotation axis is the Z axis, and the back direction of the drawing. The explanation will be given using the so-called right-handed system, which is positive from the front to the front. This two-phase flow turbine includes a moving blade 200 and one of a plurality of nozzles 210, and is configured so that the gas-liquid two-phase flow 204 flows out from the nozzle 210.

The moving blades 200 are provided at a cylindrical hub 205, a plurality of blades 201 extending in the radial direction from the hub 205 (only three blades are represented in FIG. 15), and a tip end of the blade 201. It is composed of an annular shroud 202. Some rotor blades do not have the shroud 202 installed, and in this case, the inner peripheral surface of the casing faces the tip end of the blade 201 via a clearance.

In FIG. 15, the center line CL connecting the inlet and the outlet of the nozzle 210 is displayed so as to be perpendicular to the Y axis when projected onto the plane XY plane including the X axis and the Y axis. The position where the center line CL intersects the blade 201 and the gas-liquid two-phase flow 204 flowing out of the nozzle 210 flows into the moving blade 200 in the intersecting region is the outermost wall surface of the nozzle 210 in the radial direction. It is represented by the intersection P between the extension line of the shroud 202 and the inner wall surface of the shroud 202. FIG. 16 shows a cross section of the rotor blade 200 in a plane S passing through the intersection P and including the Z axis. FIG. 16 also depicts a nozzle 210 projected perpendicular to this cross section.

As shown in FIG. 16, the center line CL of the nozzle 210 is greatly tilted with respect to the rotation axis 206 when projected onto the plane S, and the gas-liquid two-phase flow 204 flowing out of the nozzle 210 is the tip of the blade 201. It flows into the rotor blade 200 with a large inclination with respect to the shroud 202 provided at the end 201a (the inclination angle of the nozzle formed by the center line CL and the rotation axis 206 is indicated as α). Therefore, when the gas-liquid two-phase flow 204 flowing out of the nozzle 210 flows into the moving blade 200, the flow flowing into the moving blade 200 from the vicinity of the shroud 202 adheres to the inner surface of the shroud 202 and flows. Since the turning angle of the shroud 202 is too large, peeling 207 occurs at the inlet end 202a of the shroud 202, and the flow path area of the gas-liquid two-phase flow 204 becomes narrow. Therefore, there is a problem that the flow velocity in the axial direction of the rotating shaft 206 of the rotor blade 200 is accelerated, the load on the blade 201 is reduced, the work on the blade 201 is reduced, and the efficiency of the two-phase flow turbine is lowered. .. Further, even when the shroud 202 is not installed and the casing corresponding to the inner surface of the shroud 202 is installed facing the tip end 201a via a clearance, the gas-liquid two-phase flow 204 flowing out from the nozzle 210 moves. There is also a problem that the wall surface of the casing is peeled off when flowing into the blade 200, and the efficiency of the two-phase flow turbine is also lowered.

In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a blade of a two-phase flow turbine capable of improving the efficiency of the two-phase flow turbine and a two-phase flow turbine including the blade. To do.

(1) The moving blade of the two-phase flow turbine according to at least one embodiment of the present invention is
The blades of a two-phase flow turbine driven by a gas-liquid two-phase flow of fluid.
Rotatably provided rotating shaft and
A disc-shaped disc fixed to the rotating shaft and
A plurality of blades provided on the hub on the outer peripheral surface of the disc so as to be spaced apart from each other in the circumferential direction about the rotation axis.
A shroud portion facing each tip end of the plurality of blades is provided.
The shroud portion is configured such that the radius of the inner peripheral surface of the shroud portion decreases from the center of the rotation axis of the rotation shaft toward the inlet end to the exit end of the shroud portion, and the plurality of blades. Each is configured such that the radius of the tip end of the wing decreases from the center of the axis of rotation from the front edge of the wing to the trailing edge of the wing.

According to the configuration (1) above, the velocity component in the radial inward direction on the meridional surface, which is the cross section including the rotation axis, is compared with the configuration in which the vicinity of the inlet end of the shroud portion extends in the axial direction of the rotation axis. By reducing the difference between the flow angle of the gas-liquid two-phase flow and the inclination angle near the inlet end of the shroud portion, the occurrence of peeling at the inlet end is suppressed, and the efficiency of the two-phase flow turbine is improved. Can be done.

(2) In some embodiments, in the configuration of (1) above,
The front edge extends linearly from the hub-side end, which is the hub-end-side end of the blade, to the chip-side end, which is the chip-end-side end, and the chip-side end is the hub-side end. It is configured to be located on the trailing edge side in the axial direction of the rotating shaft rather than the portion.

If the distance until the gas-liquid two-phase flow flowing out of the nozzle flows into the rotor blade becomes long, the flow velocity of the gas-liquid two-phase flow before flowing into the rotor blade decreases, so the nozzle outlet becomes It is preferable to arrange the nozzles so that they are constructed in parallel and close to the front edge of the blade. However, if the nozzle outlet is made parallel to the front edge of the blade in the configuration (1) above, the nozzle outlet will not be perpendicular to the center line of the nozzle, and the nozzle will be in the radial direction. The more the gas-liquid two-phase flow located on the outside, the faster it flows out from the spout.
In addition, since the gas-liquid two-phase flow located on the outer side in the radial direction flows out from the nozzle, there is no resistance from the wall surface of the nozzle, but the gas-liquid two-phase flow located on the inner side in the radial direction does not flow out from the nozzle. There is a problem that the velocity energy of the gas-liquid two-phase flow is lost due to resistance from the wall surface of the nozzle.
According to the configuration of (2) above, by inclining the front edge of the blade, the nozzle outlet can be configured to be perpendicular to the center line of the nozzle, so that such a problem can be solved. ..

(3) In some embodiments, in the configuration of (1) above,
The front edge
The tip extends linearly from the tip-side end, which is the tip-end-side end of the blade, to the intermediate portion between the hub-side end, which is the hub-end-side end, and the tip-side end. A first portion configured so that the side end portion is located closer to the trailing edge side in the axial direction of the rotation axis than the intermediate portion.
Includes a second portion configured to extend linearly from the intermediate portion to the hub side end along a direction perpendicular to the axial direction of the rotation axis.

In the part of the front edge of the wing that does not face the nozzle outlet, the front edge of the wing passes through the area where there is no flow from the nozzle, so that it flows into the blade from that area or from the blade. A flow such as outflow occurs, and the moving blades give work to the area, so-called wind damage occurs. On the other hand, according to the configuration of (3) above, in the meridional shape of the wing, the front edge of the wing is close to the nozzle spout in parallel with the nozzle spout and at the nozzle spout at the portion facing the nozzle spout. By configuring the non-facing portion to extend along the direction perpendicular to the axis of rotation, the length of the front edge of the wing that does not face the nozzle outlet is shortened. The increase in wind damage can be suppressed.

(4) In some embodiments, in the configuration of (2) or (3) above,
Each of the plurality of blades is configured such that the radius from the center of the rotation axis to the hub end decreases from the front edge to the trailing edge.

Of the gas-liquid two-phase flow flowing from the nozzle to the rotor blade, the gas-liquid two-phase flow located near the hub surface of the rotor blade collides with the hub surface after flowing into the rotor blade and the velocity energy decreases. .. However, according to the configuration (4) above, the gas-liquid two-phase so that the distance in the radial direction from the hub surface is larger than that in the configuration in which the hub end extends in the axial direction of the rotating shaft toward the front edge. Since the flow flows into the rotor blade, the collision of the gas-liquid two-phase flow with the hub surface is suppressed, and the decrease in velocity energy can be suppressed.
In addition, the portion of the front edge of the blade that does not face the nozzle ejection port passes through a region in the vicinity where there is no flow, so that the portion flows into or out of the rotor blade from that region. A flow is generated and the moving blades give work to the area, so-called wind damage occurs. According to the configuration of (4) above, the distance from the rotation axis to the hub end decreases from the front edge to the trailing edge, so that the portion of the front edge of the wing that does not face the nozzle ejection port becomes smaller. Therefore, the increase in wind damage can be suppressed. At the same time, if the radial distance from the hub end to the tip end is defined as the blade height, the blade height can also be lowered, so that the stress on the blade cross section due to the centrifugal force acting on the root of the blade due to the rotation of the blade is reduced. It can also be suppressed.

(5) In some embodiments, in any of the configurations (1) to (4) above,
The pressure surface of the blade has a shape that is convexly curved in the direction of rotation of the blade in the blade cross section formed when the blade is cut on a cylindrical surface centered on the center of the rotation axis. The position of the most convex portion on the pressure surface is such that the ratio of the distance from the front edge to the most convex portion to the axial distance from the front edge to the trailing edge is 1/2 to 3/4. It is in a range position.

The flow of the liquid phase in the gas-liquid two-phase flow flows linearly in the direction of the gas-liquid two-phase flow in the moving blade, and eventually reaches the pressure surface of the blade. The larger the angle of incidence of the liquid phase with respect to the pressure surface when the liquid phase collides with the pressure surface, the greater the loss due to the collision of the liquid phase with the pressure surface. According to the configuration of (5) above, the most convex portion of the pressure surface in the direction of rotation of the blade is located on the trailing edge side as compared with the case where the most convex portion is located on the trailing edge side, so that the liquid phase with respect to the pressure surface is located. Since the length of the blade surface at which the incident angle of the flow is small becomes long, the loss due to the collision of the liquid phase with the pressure surface can be reduced, and the efficiency of the two-phase flow turbine can be improved.

(6) In some embodiments, in any of the configurations (1) to (5) above,
The wing includes a pressure plane and a negative pressure plane,
When the hub end of the blade is viewed from the outside in the radial direction, the hub end includes a concave curved portion on the pressure surface side that is concavely curved with respect to the rotation direction of the blade on the pressure surface side, and is concave on the pressure surface side. The curved portion extends from the front edge of the wing toward the trailing edge of the wing.
In the circumferential direction passing through the most protruding portion of the concave curved portion on the pressure surface side, the blade thickness of the blade is w, and between the pitches of the pressure surface and the negative pressure surface of each blade adjacent to the circumferential direction. If the distance of is L, (w / L) ≧ 1/3.

A part of the liquid phase flow in the gas-liquid two-phase flow flowing into the rotor blade reaches and adheres to the hub surface of the rotor blade instead of the pressure surface. The liquid phase that reaches the hub surface moves toward the pressure surface of the blade while applying a circumferential force to the hub surface, but the boundary layer of the flow of the liquid phase gradually becomes thicker, and the boundary layer becomes the rotational speed of the blade. Will turn at. Then, the swirling speed of the liquid phase becomes faster than the swirling speed of the gas-liquid two-phase flow, and rotational power is given from the blade to the boundary layer of the liquid phase. On the contrary, in the turbine that gives the fuel, the rotational power that the liquid phase flows can be given from the blade, and a loss occurs. However, according to the configuration of (6) above, the liquid phase reaching the hub surface decreases and the liquid phase directly reaching the pressure surface of the blade increases, so that the power in the rotational direction given to the blade increases. This makes it possible to improve the efficiency of the two-phase flow turbine.

(7) In some embodiments, in the configuration of (6) above,
The hub end side of the negative pressure surface of one blade of the adjacent blade in the circumferential direction and the hub end side of the pressure surface of the other blade are connected to each other at least partially from the front edge to the trailing edge. ing.

According to the configuration of (7) above, in the cross section perpendicular to the rotation axis, the hub surface of the conventional rotor blade is replaced with the pressure surface near the hub end of the pressure surface, so that the cross section of the blade surface is continuous. It consists of curves. For this reason, in order to form a structure in which the hub of the rotor blade and the blade are integrally processed, the frequency of replacement of the end mill during the blade forming work is reduced in the processing method in which the end mill is pushed from the inner surface side of the shroud to the hub side. Therefore, the workability of the blade can be improved.

(8) In some embodiments, in the configuration of (6) or (7) above,
In the cross section of the wing perpendicular to the axis of rotation, the pressure surface is concavely curved in the direction of rotation between the tip end and the hub end.
According to this configuration, it is possible to obtain the effect of the configuration of (6) above while suppressing the decrease in the flow path width of the flow path formed between the adjacent blades as much as possible.

(9) In some embodiments, in any of the configurations (1) to (8) above,
The front edge of the wing includes a first recess recessed in the meridian plane between the tip end of the wing and the hub end of the wing toward the trailing edge side of the wing.
According to this configuration, regardless of the inclination angle of the front edge with respect to the axial direction of the rotation axis, the gas-liquid two-phase flow flowing out from the nozzle is transmitted to the blade surface regardless of the inclination angle α of the nozzle formed by the center line of the nozzle and the rotation axis. Can be flushed along.

(10) In some embodiments, in the configuration of (9) above,
The trailing edge includes a second recess recessed between the tip end and the hub end toward the front edge side.
According to this configuration, at least a part of the liquid phase flowing on the pressure surface flows out from the rotor blade across the second recess. Then, as compared with the case where the second recess is not formed, the liquid phase flowing out across the second recess has a shorter distance flowing on the pressure surface. The resistance of the pressure surface to the liquid phase is reduced, and the efficiency of the two-phase flow turbine can be improved.

According to at least one embodiment of the present disclosure, the shroud portion faces the rotation axis in a direction perpendicular to the rotation axis as compared with a configuration in which the vicinity of the inlet end of the inner peripheral surface of the shroud portion extends in the axial direction of the rotation axis. By reducing the difference between the flow angle of the gas-liquid two-phase flow having a velocity component in the direction and the inclination angle near the inlet end of the shroud portion, the occurrence of peeling at the inlet end is suppressed, so that the two-phase flow turbine Efficiency can be improved.

It is a figure which shows the structure of the two-phase flow turbine which concerns on Embodiment 1 of this disclosure. It is a figure for demonstrating the operation which the gas-liquid two-phase flow flows in the flow path between two adjacent blades of a moving blade in the two-phase flow turbine which concerns on Embodiment 1 of this disclosure. It is a figure for demonstrating the action effect of the moving blade of the two-phase flow turbine which concerns on Embodiment 1 of this disclosure. It is a meridian view of the blade provided in the modified example of the moving blade of the two-phase flow turbine according to the first embodiment of the present disclosure. It is a meridian view of the blade provided in another modification of the moving blade of the two-phase flow turbine according to the first embodiment of the present disclosure. It is a meridian view of the blade provided in still another modification of the moving blade of the two-phase flow turbine according to the first embodiment of the present disclosure. It is sectional drawing of the blade provided in still another modification of the moving blade of the two-phase flow turbine which concerns on Embodiment 1 of this disclosure. FIG. 6 is a meridian view of the wing shown in FIG. It is a figure which shows the structure of the blade provided in the moving blade of the two-phase flow turbine which concerns on Embodiment 2 of this disclosure. It is sectional drawing of the blade provided in the moving blade of the two-phase flow turbine which concerns on Embodiment 2 of this disclosure. It is a figure which shows the structure of the blade provided in the moving blade of the two-phase flow turbine which concerns on Embodiment 3 of this disclosure. It is sectional drawing of the blade provided in the moving blade of the two-phase flow turbine which concerns on Embodiment 3 of this disclosure. It is a figure for demonstrating the action effect of the moving blade of the two-phase flow turbine which concerns on Embodiment 3 of this disclosure. It is sectional drawing of the blade provided in the modification of the moving blade of the two-phase flow turbine which concerns on Embodiment 3 of this disclosure. It is a meridian view of the blade provided in the moving blade of the two-phase flow turbine according to the fourth embodiment of the present disclosure. It is the figure which looked at the moving blade of the conventional two-phase flow turbine in the axial direction of the rotation axis. It is a meridian view of the blade provided in the moving blade of a conventional two-phase flow turbine.

Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention to that alone, but are merely explanatory examples.

(Embodiment 1)
As shown in FIG. 1, the two-phase flow turbine 1 according to the first embodiment of the present disclosure is, for example, an impulse turbine provided in place of an expansion valve in the refrigeration cycle of a refrigerator, and is provided by a refrigerant circulating in the refrigeration circuit. Driven. The two-phase flow turbine 1 includes a moving blade 10 and a nozzle 20. The moving blades 10 are equally spaced between the disk-shaped disc 11, the rotating shaft 12 fixed to the disc 11 so as to pass through the center of the disc 11, and the outer peripheral surface 11a of the disc 11, that is, the hub surface of the moving blade 10. It is provided with a plurality of blades 13 that are opened and fixed. That is, the plurality of blades 13 are provided so as to be spaced apart from each other in the circumferential direction about the rotation shaft 12. With this configuration, when the blade 13 rotates in the circumferential direction (rotation direction D1) about the rotation shaft 12, the disk 11 rotates with this rotation, that is, the rotation shaft 12 fixed to the disk 11 rotates in the rotation direction D. It is designed to rotate to.

The nozzle 20 is provided so that a flow path 21 is formed inside the nozzle 20 so as to extend from the inflow port 20b to the spout 20a and the spout 20a faces the blade 13. The flow path area of the flow path 21 decreases from the inflow port 20b toward the spout 20a, the flow path area becomes the minimum at the position 20c between the inflow port 20b and the spout 20a, and from the position 20c to the spout 20a. It is configured so that the flow path area increases toward it.

In the plane corresponding to the plane S (see FIG. 15) in FIG. 2, the moving blade 10 further includes a shroud portion 50 in the form of a cylindrical shroud provided fixedly to each tip end 16 of each blade 13. There is. The shroud portion 50 is not limited to the shroud fixed to each tip end 16 of each wing 13 as long as it is configured to face each tip end 16 of each wing 13, and each tip of each wing 13 is not limited to the shroud portion 50. It may be a casing provided so as to open a gap with respect to the end 16.

The shroud portion 50 is a curved portion in which the radius r1 of the inner peripheral surface 50c of the shroud portion 50 centered on the rotation axis center O of the rotation shaft 12 decreases from the inlet end 50a to the outlet end 50b of the shroud portion 50. The peripheral surface portion 51 is included. That is, the curved inner peripheral surface portion 51 is a part of the inner peripheral surface 50c near the inlet end 50a. In the cross section of the rotating shaft 12 along the axial direction (FIG. 2), the downstream inner peripheral surface 52 on the outlet end 50b side of the curved inner peripheral surface portion 51 is parallel to the outer surface of the rotating shaft 12. The curved inner peripheral surface portion 51 has a shape that is convexly curved with respect to the outer surface of the rotating shaft 12. Further, in the wing 13, the radius r2 of the chip end 16 centered on the center O of the rotation axis is from the front edge 18 of the wing 13 to the trailing edge 19 of the wing 13 so as to correspond to the form near the inlet end 50a of the shroud portion 50. It is configured to include a portion 16a that decreases towards.

Next, the operation of the two-phase flow turbine 1 according to the first embodiment of the present disclosure will be described.
As shown in FIG. 1, the liquid refrigerant circulating in the refrigeration circuit flows into the nozzle 20 through the inflow port 20b and flows through the flow path 21. When the liquid refrigerant flows into the flow path 21 from the inflow port 20b, the flow path area of the flow path 21 decreases to the position 20c, so that the refrigerant is accelerated while flowing to the position 20c. On the contrary, since the flow path area of the flow path 21 increases from the position 20c to the ejection port 20a, the refrigerant is depressurized while flowing from the position 20c to the ejection port 20a. When the refrigerant is decompressed and reaches a damp area, a part of the refrigerant vaporizes and the volume increases rapidly. The refrigerant expands between the position 20c and the ejection port 20a, and at the ejection port 20a, the energy of the pressure difference is converted into a velocity, resulting in a gas-liquid two-phase flow in which a liquid phase and a gas phase are mixed. The refrigerant is ejected from the nozzle 20 to the rotor blade 10 as a gas-liquid two-phase flow.

When the gas-liquid two-phase flow of the refrigerant ejected from the nozzle 20 to the moving blade 10 flows through the flow path 40 of the moving blade 10, the velocity energy of the gas-liquid two-phase flow gives a force to the blade 13 and its reaction force. The blade 13 rotates in the rotation direction D1. The disk 11 rotates in the rotation direction D1 with the rotation of the blade 13, whereby the rotation shaft 12 rotates in the rotation direction D, and rotational power can be obtained from the two-phase flow turbine 1.

In the plane corresponding to the plane S (see FIG. 15) in FIG. 2, the gas-liquid two-phase flow 100 ejected toward the moving blade 10 is in the direction perpendicular to the rotation axis 12 toward the rotation axis 12. It has a velocity component. Therefore, when the gas-liquid two-phase flow 100 flows into the flow path 40, the gas-liquid two-phase flow 100 grabs the inlet end 50a at a portion close to the shroud portion 50. In the first embodiment, since the curved inner peripheral surface portion 51 having a shape curved convexly with respect to the outer surface of the rotating shaft 12 is formed in the vicinity of the inlet end 50a of the shroud portion 50, the gas-liquid two-phase flow The flow angle of 100 (the angle formed by the direction of the gas-liquid two-phase flow 100 with respect to the rotation axis 12) and the inclination angle of the shroud portion 50 near the inlet end 50a (the tangent line of the curved inner peripheral surface portion 51 near the inlet end 50a). The difference from the angle formed with respect to the rotating shaft 12) becomes small. That is, when the gas-liquid two-phase flow 100 flows into the flow path 40, the gas-liquid two-phase flow 100 comes into smooth contact with the curved inner peripheral surface portion 51 at a portion close to the shroud portion 50. As a result, the occurrence of peeling at the inlet end 50a is suppressed, so that the efficiency of the two-phase flow turbine 1 (see FIG. 1) can be improved.

In the two-phase flow turbine 1 in the plane corresponding to the plane S (see FIG. 15) in FIG. 3, when the distance between the gas-liquid two-phase flow 100 flowing out of the nozzle 20 and flowing into the moving blade 10 becomes long, the turbine moves. Since the flow velocity of the gas-liquid two-phase flow 100 decreases before flowing into the blade 10, it is preferable to arrange the nozzle 20 so that the ejection port 20a of the nozzle 20 is parallel to the front edge 18 of the blade 13. However, when trying to make the nozzle 20 outlet 20a parallel to the front edge 18 of the blade 13 in the configuration of FIG. 2, the nozzle 20 ejection port 20a becomes the inlet 20b (see FIG. 1) as shown in FIG. And, the configuration is not perpendicular to the center line CL connecting the centers of the spouts 20a. Since the flow in the nozzle 20 is accelerated along the distance along the center line CL and becomes a substantially constant flow velocity in the cross section CS perpendicular to the center line CL, the ejection port 20a of the nozzle 20 is not perpendicular to the center line CL. In this case, the flow velocity at the spout 20a is distributed. The gas-liquid two-phase flow 100 located on the outer side in the radial direction in the nozzle 20 is configured to flow out from the ejection port 20a earlier. Then, since the gas-liquid two-phase flow 100 located on the outer side in the radial direction flows out from the nozzle 20, there is no resistance from the wall surface of the nozzle 20, but the gas-liquid two-phase flow 100 located on the inner side in the radial direction flows out from the nozzle 20. Since it does not flow out, it receives resistance from the wall surface of the nozzle 20, and there is a problem that the velocity energy of the gas-liquid two-phase flow 100 is lost.

As a configuration for solving such a problem, in the plane corresponding to the plane S (see FIG. 15) in FIG. 4, the front edge 18 is from the hub side end portion 18b, which is the end portion of the wing 13 on the hub end 17 side. It is configured so that it extends linearly to the chip side end 18a, which is the end on the chip end 16 side, and the chip side end 18a is located on the trailing edge 19 side in the axial direction of the rotating shaft 12 with respect to the hub side end 18b. can do. When the front edge 18 is configured in this way, when the nozzle 20 is arranged so that the nozzle 20 is parallel to the front edge 18 of the blade 13, the center line CL is set with respect to the nozzle 20 a. Can be vertical.

Further, an example of modification to the configuration of FIG. 4 is shown in FIG. 4a. In this modification, the front edge 18 includes a first portion 18d and a second portion 18e. The first portion 18d extends linearly from the chip side end portion 18a to the intermediate portion 18c between the hub side end portion 18b and the chip side end portion 18a, and the chip side end portion 18a rotates more than the intermediate portion 18c. It is configured to be located on the trailing edge 19 side in the axial direction of 12. The second portion 18e is configured to extend linearly from the intermediate portion 18c to the hub side end portion 18b along a direction perpendicular to the axial direction of the rotating shaft 12.

The second portion 18e, which is a portion of the front edge 18 of the blade 13 that does not face the ejection port 20a of the nozzle 20, flows into the rotor blade 10 from that region by passing through a region in the vicinity where there is no flow. A flow of flow or outflow from the moving blade 10 occurs, and the moving blade 10 gives work to the region, so-called wind damage occurs. On the other hand, the second portion 18e of the nozzle 20 not facing the ejection port 20a is configured to extend along the direction perpendicular to the rotation axis 12, so that the nozzle 20 of the front edge 18 is ejected. Since the length of the portion not facing the outlet 20a is shortened, an increase in wind damage can be suppressed.

Further, in each of the configurations of FIGS. 2 and 4 and 4a, of the gas-liquid two-phase flow 100 flowing from the nozzle 20 into the moving blade 10, the outer peripheral surface 11a of the disk 11 to which the blade 13 is fixed, that is, the hub of the moving blade 10. The gas-liquid two-phase flow 100 located near the surface has a problem that the velocity energy is reduced by colliding with the hub surface after flowing into the moving blade 10.

As a configuration for solving such a problem, in the plane corresponding to the plane S (see FIG. 15) in FIG. 5, the blade 13 has a hub end 17 centered on the center O of the rotation axis with respect to the configuration of FIG. The radius r3 of the can be configured to include a curved edge portion 17a which is a portion where the radius r3 decreases from the front edge 18 toward the trailing edge 19. That is, the curved edge portion 17a is a part of the hub end 17 near the front edge 18. In the cross section of the rotating shaft 12 along the axial direction (FIG. 5), the hub end 17 on the trailing edge 19 side of the curved edge 17a is relative to the hub end 17 of the conventional structure extending axially in the meridional plane. It has a concavely curved shape.

According to such a configuration, the radius is increased from the hub side end portion 18b, which has a larger radial distance from the hub surface than the configuration in which the hub end 17 extends in the axial direction of the rotating shaft 12 toward the front edge 18. Since the gas-liquid two-phase flow 100 smoothly flows into the moving blade 10 along the concave surface so as to be smaller, the collision of the gas-liquid two-phase flow 100 with the hub surface is suppressed, and the velocity energy is reduced. It can be suppressed. Further, according to such a configuration, the radius r3 decreases from the front edge 18 toward the trailing edge 19 in the vicinity of the inlet of the moving blade 10, so that the nozzle 20 of the front edge 18 of the blade 13 becomes the ejection port 20a. Since the non-faced portion becomes smaller, an increase in wind damage can be suppressed. At the same time, if the radial distance from the hub end 17 to the tip end 16 is defined as the blade height, the blade height can also be lowered, so that the blade is caused by the centrifugal force acting on the root of the blade 13 due to the rotation of the blade 13. It is also possible to suppress the stress in the cross section.

Further, as shown in FIG. 6, the recess 30 recessed in the rotation direction D1 of the blade 13 may be formed on the pressure surface 14 of the blade 13 with respect to the configuration of FIG. The recess 30 is a curved portion 31 that is recessed and curved in an arc shape in the rotation direction D1 of the blade 13, and is flat from the tip side end portion 31a, which is the end portion of the curved portion 31 on the tip end 16 side, to the tip end 16. The first flat surface 32 extending may include a second flat surface 33 extending flat from the hub side end 31b, which is the end of the curved portion 31 on the hub end 17 side, to the hub end 17. As shown in FIG. 7, the recess 30 may be formed so as to extend from the front edge 18 to the trailing edge 19, for example. The recess 30 may be formed so as to partially extend between the front edge 18 and the trailing edge 19.

The gas-liquid two-phase flow 100 flowing out of the nozzle 20 in the plane corresponding to the plane S (see FIG. 15) in FIG. 7 is a gas phase and a liquid phase due to the liquid phase being refined by surface tension into droplets. Is a separated flow. If the blade shape of the blade 13 is designed according to the gas phase, the gas phase can flow along the blade surface of the blade 13, but the liquid phase is linear in the direction of the gas-liquid two-phase flow 100. The liquid phase flow 102 is formed on the pressure surface 14 after the droplets collide with the pressure surface 14 and are accumulated again. The liquid phase flows along the pressure plane 14, then passes through the trailing edge 19 and flows out of the flow path 40 (see FIG. 2). The friction of the liquid phase flow 102 along the pressure surface 14 with respect to the pressure surface 14 forms a boundary layer on the pressure surface 14. This boundary layer rotates at the rotational speed of the blade 13 in the vicinity of the pressure surface 14. The centrifugal force due to this rotation acts on the boundary layer, so that the boundary layer moves in the direction from the hub end 17 to the chip end 16 (outward in the radial direction of the blade height).

On the other hand, when the recess 30 is formed on the pressure surface 14, the flow 102 of the liquid phase along the pressure surface 14 becomes a flow along the recess 30. Even if centrifugal force acts on the boundary layer of the liquid phase flowing along the recess 30, the first flat surface 32 of the recess 30 suppresses the movement toward the tip end 16 in the blade height direction, so that the pumping action is used. The loss is suppressed and the efficiency of the two-phase flow turbine 1 can be improved. Further, since the liquid phase mainly flows on the pressure surface 14 toward the trailing edge 19 along the curved portion 31 having a large curvature, the liquid phase flows along the surface having a small curvature as compared with the case where the liquid phase flows. The length of the wet edge at which the phase contacts the pressure surface 14 (the length of the portion where the liquid phase contacts the pressure surface 14 in the blade height direction) becomes short, and the resistance of the liquid phase to the pressure surface 14 decreases. Further, the flow of the liquid phase 102 has a shorter movement distance in the blade height direction than the flow of the liquid phase when the recess 30 is not formed on the pressure surface 14, so that the liquid phase with respect to the pressure surface 14 Resistance becomes smaller. As a result, the efficiency of the two-phase flow turbine 1 (see FIG. 1) can be improved.

(Embodiment 2)
Next, the moving blades of the two-phase flow turbine according to the second embodiment will be described. The moving blade of the two-phase flow turbine according to the second embodiment has a limited configuration of the negative pressure surface of the blade 13 as compared with the first embodiment. In the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. 8 and 9 referred to in the second embodiment are views of the shape of the blade 13 viewed from the outside of the radius.

As shown in FIG. 8, the negative pressure surface 15 of the wing 13 includes a negative pressure surface side convex curved portion 60 formed so as to extend from the front edge 18 toward the trailing edge 19. The convex curved portion 60 on the negative pressure surface side is configured so that the blade thickness on the negative pressure surface 15 side is larger than the blade thickness on the pressure surface 14 side. As shown in FIG. 9, the negative pressure surface side convex curved portion 60 has a blade 13 in a blade cross section formed when the blade 13 is cut on a cylindrical surface centered on the center O of the rotation axis (see FIG. 2 and the like). It is curved convexly toward the rotation direction D1 of. Further, the pressure surface 14 of the blade 13 has a shape that is convexly curved in the rotation direction D1.

As shown in FIG. 8, the most convex portion 14a of the pressure surface 14 toward the rotation direction D1 is the most convex portion from the front edge 18 with respect to the distance L3 from the front edge 18 to the trailing edge 19 at the tip end 16. The ratio X (= L4 / L3) of the distance L4 to 14a is in the range of 1/2 to 3/4. Other configurations are the same as those in the first embodiment. The configuration of FIG. 8 is based on the configuration in the vicinity of the front edge 18 of the wing 13 as shown in FIG. 3, but is based on the configuration of the vicinity of the front edge 18 of the wing 13 as shown in FIG. 2 or FIG. 2 may be configured.

Next, the operation of the two-phase flow turbine 1 according to the second embodiment of the present disclosure will be described with reference to FIG. Since only the flow of the gas-liquid two-phase flow in the moving blade 10 (see FIG. 1) differs between the operation of the first embodiment and the operation of the second embodiment, the following description describes the two-phase gas-liquid phase in the moving blade 10. Only the flow of the flow will be described.

In the nozzle 20 (see FIG. 1), the acceleration of the gas phase is larger than the acceleration of the liquid phase, and the flow velocity of the gas phase is larger than the flow velocity of the liquid phase. Therefore, the relative flow velocity of the gas phase as seen from the moving blade 10 The flow angle θ ₂ of the relative flow velocity of the liquid phase is larger than the flow angle θ ₁ . Since the power balance between the gas phase and the liquid phase of the power of the two-phase flow turbine 1 (see FIG. 1) is larger in the latter, the liquid phase at the front edge 18 is required to reduce the loss of the liquid phase. It is preferable to design the blade 13 so that the incident of the flow 102 is small. With such a design, the incident of the gas phase flow 101 with respect to the negative pressure surface 15 becomes large.

On the other hand, in the second embodiment, since the negative pressure surface side convex curved portion 60 is formed on the negative pressure surface 15 so as to extend from the front edge 18 toward the rear edge 19, the gas phase flow 101 is the front edge. After passing through 18, the negative pressure surface 15 (the convex curved portion 60 on the negative pressure surface side) comes into smooth contact from the front edge 18 to the trailing edge 19, so that the gas phase loss due to the incident is reduced, and the gas phase loss is reduced. The efficiency of the multiphase turbine 1 can be improved.

On the other hand, the liquid phase flow 102 in the gas-liquid two-phase flow 100 flows linearly in the flow path 40 in the direction of the gas-liquid two-phase flow 100, and eventually reaches the pressure surface 14 of the blade 13. The larger the incident angle θ of the liquid phase with respect to the pressure surface 14 when the liquid phase collides with the pressure surface 14, the greater the loss due to the collision of the liquid phase with the pressure surface 14. In the second embodiment, the most convex portion 14a of the pressure surface 14 toward the rotation direction D1 is the most convex portion from the front edge 18 with respect to the distance L3 from the front edge 18 to the trailing edge 19 at the tip end 16. Since the ratio X (= L4 / L3) of the distance L4 to 14a is in the range of 1/2 to 3/4, when the most convex portion 14a is located closer to the front edge 18 (X <1). (In the case of / 2), the incident angle θ of the liquid phase flow 102 with respect to the pressure surface 14 is smaller. As a result, the loss due to the collision of the liquid phase with the pressure surface 14 is reduced, and the efficiency of the two-phase flow turbine 1 can be improved.

(Embodiment 3)
Next, the moving blades of the two-phase flow turbine according to the third embodiment will be described. The moving blade of the two-phase flow turbine according to the third embodiment has a limited configuration of the pressure surface of the blade 13 with respect to the first or second embodiment. Hereinafter, the third embodiment will be described with a configuration in which the configuration of the pressure surface of the blade 13 is limited to the configuration of the first embodiment, but the configuration of the pressure surface of the blade 13 is limited to the configuration of the second embodiment. 3 may be configured with. In the third embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, FIG. 10 referred to in the third embodiment is a view of the shape of the blade 13 viewed from the outside of the radius.

As shown in FIG. 10, the hub end 17 of the blade 13 includes a pressure surface side concave curved portion 70 that is concavely curved toward the rotation direction D1 of the blade 13 on the pressure surface 14 side. The pressure surface side concave curved portion 70 extends from the front edge 18 toward the trailing edge 19. In the rotation direction D1 passing through the most concave portion 70a in the rotation direction D1 of the concave curved portion 70 on the pressure surface side, the blade thickness of the blade 13 is set to w, and the pressure surface of each blade 13 adjacent to the rotation direction D1. Assuming that the distance between the pitches of 14 and the negative pressure surface 15 is L, (w / L) ≧ 1/3, preferably 1/3 ≦ (w / L) ≦ 2/3.

As shown in FIG. 11, in a cross section that crosses the concave curved portion 70 on the pressure surface side in FIG. 10 and is perpendicular to the center O of the rotation axis, the pressure surface 14 of the blade 13 is formed by the tip end 16 and the hub end 17. It is curved convexly toward the negative pressure surface 15 in the rotation direction D1. Other configurations are the same as those in the first embodiment.

Next, the operation of the two-phase flow turbine 1 according to the third embodiment of the present disclosure will be described. Since only the flow of the gas-liquid two-phase flow in the moving blade 10 (see FIG. 1) differs between the operation of the first embodiment and the operation of the third embodiment, the following description describes the two-phase gas-liquid phase in the moving blade 10. Only the flow of the flow will be described.

As shown in FIG. 12A, when the hub end 17 does not include the pressure surface side concave curved portion 70 in FIG. 10, the gas-liquid two-phase flow flowing into the rotor blade 10 in the cross section perpendicular to the rotating shaft 12 A part of the liquid phase flow 102 of the above reaches and adheres to the outer peripheral surface 11a (hub surface of the moving blade 10) of the disk 11 instead of the pressure surface 14. The liquid phase 103 that has reached the outer peripheral surface 11a of the disk 11 moves toward the pressure surface 14 while applying a force in the circumferential direction to the outer peripheral surface 11a, but the boundary layer of the flow of the liquid phase 103 gradually becomes thicker and becomes a boundary. The layer eventually turns with the disc 11. Then, the swirling speed of the liquid phase 103 becomes faster than the swirling speed of the gas-liquid two-phase flow, and rotational power is applied from the blade 13 to the boundary layer of the flow of the liquid phase 103. On the contrary, in the turbine that applies the rotational power to the blade 13, the rotational power that the liquid phase 103 flows from the blade 13 can be applied, resulting in a loss.

On the other hand, in the third embodiment, as shown in FIG. 12B, the hub end 17 of the blade 13 in the cross section perpendicular to the rotation axis 12 is directed toward the rotation direction D1 in FIG. 10 on the pressure surface 14 side. Since the concave curved portion 70 on the pressure surface side is included, the range of the pressure surface 14 is expanded in the circumferential direction in the vicinity of the outer peripheral surface 11a of the disk 11 in the portion including the concave curved portion 70 on the pressure surface side. That is, the range in which the outer peripheral surface 11a of the disk 11 is exposed is reduced. Then, the liquid phase reaching the outer peripheral surface 11a of the disk 11 decreases, and the liquid phase reaching the pressure surface 14 of the blade 13 increases. Therefore, the power in the rotational direction given to the blade 13 is increased. The efficiency of the two-phase flow turbine can be improved.

In the third embodiment, as shown in FIG. 11, the pressure surface 14 of the blade 13 crosses the pressure surface side concave curved portion 70 in FIG. 10 and is perpendicular to the rotation axis 12 (see FIG. 2 and the like). , The tip end 16 and the hub end 17 are curved in a convex shape in the rotation direction D1. If the pressure surface 14 is not curved convexly toward the rotation direction D1 as shown by the broken line BL in FIG. 11, the flow path of the flow path 40 (see FIG. 1) formed between the pressure surface 14 and the adjacent blade. The width will decrease. Therefore, since the pressure surface 14 is curved in a convex shape toward the rotation direction D1, the liquid phase reaching the pressure surface 14 of the blade 13 is maintained while suppressing the decrease in the flow path width of the flow path 40 as much as possible. It can be increased to improve the efficiency of the two-phase flow turbine.

In the third embodiment, as shown in FIG. 11, the pressure surface side concave curved portion 70 in FIG. 10 is in contact with the outer peripheral surface 11a of the disc 11 between the adjacent blades 13 in the cross section perpendicular to the rotation axis 12. , Not limited to this form. As shown in FIG. 13, a pressure surface 14 that is convexly curved in the rotation direction D1 between the tip end 16 and the hub end 17 is a negative pressure surface of the adjacent blade 13 along the outer peripheral surface 11a of the disc 11. It may extend to 15. That is, the hub ends 17 of the adjacent blades 13 may be connected to each other. Further, the portion where the hub ends 17 of the adjacent blades 13 are connected to each other may be the entire portion between the front edge 18 and the trailing edge 19 of the blade 13, or a part between the front edge 18 and the trailing edge 19. You may. In the portion where the hub ends 17 of the adjacent blades 13 are not connected to each other, it is necessary to replace the end mill 300 in the middle when processing the blades 13, but the hub ends 17 of the adjacent blades 13 are connected to each other. In the portion, it is not necessary to replace the end mill 300 in the middle when processing the blade 13. By connecting the hub ends 17 of the adjacent blades 13 to each other, the frequency of replacement of the end mill 300 during the forming work of the blade 13 can be reduced, so that the workability of the blade 13 can be improved. If the hub ends 17 of the adjacent blades 13 are connected to each other from the front edge 18 to the trailing edge 19 of the blade 13, it is not necessary to replace the end mill 300 during the forming work of the blade 13, and the blade 13 does not need to be replaced. Workability can be further improved.

(Embodiment 4)
Next, the moving blades of the two-phase flow turbine according to the fourth embodiment will be described. The moving blades of the two-phase flow turbine according to the fourth embodiment are limited to the configuration of the front edge 18 of the blade 13 on the meridian plane for each of the first to third embodiments. In the following, the fourth embodiment will be described in which the configuration of the front edge 18 of the wing 13 is limited to the configuration shown in FIG. 5 of the first embodiment, but the configuration of FIG. 2, FIG. 4 or FIG. 4a of the first embodiment will be described. The fourth embodiment may be configured by limiting the configuration of the front edge 18 of the wing 13 to the configuration shown in any of the configurations or the configuration of the second embodiment. In the fourth embodiment, the same reference numerals as those of the constituent requirements of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 14, the front edge 18 of the wing 13 includes a first recess 80 recessed between the tip end 16 of the wing 13 and the hub end 17 toward the trailing edge 19 side. Further, although not an essential configuration requirement in the fourth embodiment, the trailing edge 19 may include a second recess 90 recessed toward the front edge 18 side between the tip end 16 of the wing 13 and the hub end 17. .. Other configurations are the same as those in the first embodiment.

In the first embodiment, as shown in FIG. 5, the front edge 18 of the blade 13 is tilted in order to use the nozzle 20 having the nozzle 20a having the ejection port 20a perpendicular to the direction of the outflow gas-liquid two-phase flow 100. On the other hand, in the fourth embodiment, the first recess 80 has a shape corresponding to the outer shape of the ejection port 20a of the nozzle 20, so that a part of the nozzle 20 is inserted into the first recess 80. Since 20 can be arranged, a nozzle 20 having a nozzle 20a perpendicular to the direction of the outflowing gas-liquid two-phase flow 100 can be used regardless of the inclination angle of the front edge 18.

Further, by providing the second recess 90 on the trailing edge 19, at least a part of the liquid phase flowing on the pressure surface 14 of the blade 13 crosses the second recess 90 and flows out from the rotor blade 10. Then, as compared with the case where the second recess 90 is not formed, the liquid phase in which the distance flowing on the pressure surface 14 is shortened increases, so that the resistance of the liquid phase to the pressure surface 14 becomes small, and the two-phase flow turbine The efficiency of 1 (see FIG. 1) can be improved.

In the first to fourth embodiments, the two-phase flow turbine 1 has been described by taking as an example an impulse turbine provided in place of the expansion valve in the refrigeration cycle of the refrigerator, but the present invention is not limited to this. The two-phase flow turbine 1 may be a turbine for an organic Rankine cycle, a steam turbine for geothermal use, or the like, and is a turbine that obtains power by expanding the flow from a high-pressure liquid or a gas-liquid two-phase fluid of various plants to a low pressure. If so, the application is not limited.

In the first to fourth embodiments, the term "two-phase flow" has been used without a strict definition, but in the two-phase flow in the present disclosure, one kind of substance has two phases, a liquid phase and a gas phase. It is not limited to a substance, but is a substance composed of a plurality of liquids and gases such as when a component in the air is dissolved in water, and the gas phase state and the liquid under certain conditions. It means a flow in which the phase state is in equilibrium.

In the configuration described in the first to fourth embodiments, for example, a Pelton turbine in which the flow of the liquid phase from the ejection port of the nozzle is discharged into the gas phase at a high speed and the gas phase exists around the flow of the liquid phase. It can also be applied to turbines powered by liquids of the form.

1 Two-phase flow turbine 10 Blade 11 Disc
11a Outer surface 12 (of disk) Rotating shaft 13 Wing 14 Pressure surface 14a (Pressure surface) Most convex part 15 Negative pressure surface 16 Chip end 17 Hub end 17a Curved edge 18 Front edge 18a (Front edge) Chip side end Part 18b (front edge) Hub side end 18c (front edge) Middle part 18d (front edge) First part 18e (front edge) Second part 19 Rear edge 20 Nozzle 20a Spout 20b Inlet 20c ( Position (between the inlet and outlet of the nozzle) 21 Flow path 40 Flow path 50 Shroud part 50a (of the shroud part) Inlet end 50b (of the shroud part) Outlet end 50c (of the shroud part) Inner peripheral surface 51 Inside the curve Peripheral surface portion 52 Downstream side inner peripheral surface 60 Negative pressure surface side convex curved portion 70 Pressure surface side concave curved portion 70a (Pressure surface side concave curved portion) Most concave portion 80 First concave portion 90 Second concave portion 100 Gas-liquid two-phase Flow 101 Gas phase flow 102 Liquid phase flow CaL Camber line O Rotation axis center R Rotation axis rotation direction R1 Blade rotation direction α Nozzle inclination angle between the nozzle center line and the rotation axis

Claims (10)

The blades of a two-phase flow turbine driven by a gas-liquid two-phase flow of fluid.
Rotatably provided rotating shaft and
A disc-shaped disc fixed to the rotating shaft and
A plurality of blades provided on the hub on the outer peripheral surface of the disc so as to be spaced apart from each other in the circumferential direction about the rotation axis.
A shroud portion facing each tip end of the plurality of blades is provided.
The shroud portion is configured such that the radius of the inner peripheral surface of the shroud portion decreases from the center of the rotation axis of the rotation shaft toward the outlet end to the outlet end of the shroud portion, and the plurality of blades. Each is a two-phase flow turbine drive blade configured such that the radius of the tip end of the blade decreases from the center of the rotation axis toward the trailing edge of the blade. The front edge extends linearly from the hub-side end, which is the hub-end-side end of the blade, to the chip-side end, which is the chip-end-side end, and the chip-side end is the hub-side end. The moving blade of the two-phase flow turbine according to claim 1, which is configured to be located on the trailing edge side in the axial direction of the rotating shaft with respect to the portion. The front edge
The tip extends linearly from the tip-side end, which is the tip-end-side end of the blade, to the intermediate portion between the hub-side end, which is the hub-end-side end, and the tip-side end. A first portion configured so that the side end portion is located closer to the trailing edge side in the axial direction of the rotation axis than the intermediate portion.
The two-phase according to claim 1, further comprising a second portion configured to extend linearly from the intermediate portion to the hub-side end along a direction perpendicular to the axial direction of the rotating shaft. Flow turbine blades. The two-phase flow according to claim 2 or 3, wherein each of the plurality of blades is configured such that the radius from the center of the rotation axis to the end of the hub decreases from the front edge toward the trailing edge. Turbine blades. The pressure surface of the blade has a shape that is convexly curved in the direction of rotation of the blade in the blade cross section formed when the blade is cut on a cylindrical surface centered on the center of the rotation axis. The position of the most convex portion on the pressure surface is such that the ratio of the distance from the front edge to the most convex portion to the axial distance from the front edge to the trailing edge is 1/2 to 3/4. The vane of a two-phase flow turbine according to any one of claims 1 to 4, which is located in a range. The wing includes a pressure plane and a negative pressure plane,
When the hub end of the blade is viewed from the outside in the radial direction, the hub end includes a concave curved portion on the pressure surface side that is concavely curved with respect to the rotation direction of the blade on the pressure surface side, and is concave on the pressure surface side. The curved portion extends from the front edge of the wing toward the trailing edge of the wing.
In the circumferential direction passing through the most protruding portion of the concave curved portion on the pressure surface side, the blade thickness of the blade is w, and between the pitches of the pressure surface and the negative pressure surface of each blade adjacent to the peripheral direction. The rotor blade of the two-phase flow turbine according to any one of claims 1 to 5, wherein (w / L) ≥ 1/3, where L is the distance between the two. The hub end side of the negative pressure surface of one of the blades adjacent to each other in the circumferential direction and the hub end side of the pressure surface of the other blade are connected to each other at least partially from the front edge to the trailing edge. The moving blade of the two-phase flow turbine according to claim 6. 2. The second aspect of claim 6 or 7, wherein in the cross section of the blade perpendicular to the rotation axis, the pressure surface is concavely curved in the rotation direction between the tip end and the hub end. The moving blades of a multiphase turbine. Any one of claims 1-8, wherein the front edge of the blade comprises a first recess recessed in the meridional plane between the tip end of the blade and the hub end of the blade toward the trailing edge side of the blade. The blades of the two-phase flow turbine described in the section. The rotor blade of the two-phase flow turbine according to claim 9, wherein the trailing edge includes a second recess recessed toward the front edge side between the tip end and the hub end.

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