JP2019143535A - Counter-rotating impeller and fluid machine - Google Patents

Abstract

To provide a counter-rotating impeller having large recoverable energy, and a fluid machine.SOLUTION: A counter-rotating impeller 40 comprises first and second impellers 20 and 30 arranged coaxially. The first impeller 20 has an axial flow type impeller 21 and a mixed flow type impeller 22 arranged in an axis direction. The second impeller 30 is a centrifugal impeller that rotates in a direction opposite to a rotational direction of the first impeller 20, and is arranged at a position continuous with the mixed flow type impeller 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a counter rotating impeller composed of first and second impellers arranged coaxially and a fluid machine having counter rotating impellers.

  Small hydropower generation is positioned as one of the renewable energies and is being introduced to respond to global warming issues and diversify energy supply systems. Among small hydropower generation, relatively large-scale power generation facilities with an output of about 100 kW to 1000 kW are spreading, but for further expansion of small hydropower generation, the output is about 0.1 kW to about 1 kW. Development of pico hydroelectric power generation is desired. Pico hydroelectric power generation makes effective use of water resources that are not well used, such as agricultural waterways, simple water supply, and small rivers, and performs large-scale construction such as drawing foundations and water pipes for installing water turbines. There is an advantage that it is not necessary, is easy to set up and has little impact on the natural environment.

  The water turbine for pico hydroelectric power generation is required to have portability in order to be easily installed by being carried to an agricultural waterway or a simple water supply. In the non-patent document 1, the applicant has proposed a small water wheel for pico hydroelectric power generation. The water wheel of Non-Patent Document 1 is a so-called contra-rotating type, and the front impeller and the rear impeller are arranged coaxially. Each impeller is an axial flow type, and the blades are attached to rotate in directions opposite to each other when fluid (water) flows from front to back.

  Such a counter-rotating type water wheel uses two impellers to collect fluid energy at each impeller, so the diameter of the impeller is larger than when the same fluid energy is collected by one impeller. Is small and can be miniaturized. In addition, since the swirl speed component of the fluid energy at the front impeller exit can be recovered by the rear impeller, and the swirl speed component of the fluid energy at the rear impeller exit can be eliminated, there is a friction loss proportional to the square of the speed. The fluid energy that can be recovered is large and highly efficient.

Shigemitsu, et al., “Effects of spoke shape of counter-rotating small hydro turbine on performance and internal flow”, Turbomachine, Vol. 44, No. 2, 2016.

  In the counter-rotating water turbine of Non-Patent Document 1, in order to increase the recoverable energy, the flow rate of the fluid flowing through the impeller may be increased to increase the input energy input to the turbine. However, when the fluid flow rate is increased, the efficiency may be deteriorated and the impeller may be damaged. In order to prevent this, it is necessary to increase the size of the impeller by increasing the diameter of the impeller. However, if the size is increased, the portability required for the water turbine for pico hydropower generation is lost, so there is room for improvement.

  The present invention has been made paying attention to the above-described problems, and an object thereof is to provide a counter-rotating impeller and a fluid machine that are small and have a large recoverable energy.

  A counter-rotating impeller according to the present invention includes first and second impellers arranged coaxially, and the first impeller includes an axial flow impeller and a mixed flow impeller arranged in the axial direction. The second impeller is a centrifugal impeller that rotates in a direction opposite to the rotation direction of the first impeller, and is disposed at a position that is continuous with the mixed flow impeller. .

  When the counter-rotating impeller of the present invention is used as an impeller for a water wheel or a windmill, when a fluid such as water or air is input toward the first impeller, the first impeller receives energy from the fluid. Get and rotate. The fluid exits the first impeller and flows into the second impeller, the second impeller obtains energy from the fluid and rotates in the opposite direction to the first impeller, and the fluid is the second impeller. Spill from. Energy is extracted by energy extraction means such as a generator connected to the first impeller and the second impeller.

  In the centrifugal impeller, the outer diameters of the fluid inlet and the outlet are different, and the difference in the peripheral speed of the inlet and the peripheral speed of the outlet causes a difference in the centrifugal force. Therefore, the difference in the centrifugal force becomes energy. On the other hand, since the outer diameter of the fluid inlet and outlet is the same, the axial flow impeller converts the centrifugal force into energy because there is no difference in the peripheral velocity of the inlet and the peripheral velocity of the outlet and no difference in centrifugal force. I can't. Therefore, when each impeller has the same diameter, fluid flow rate, and rotational speed, the centrifugal impeller imposes a higher load than the axial flow impeller, that is, the fluid is input to the centrifugal impeller. It is possible to increase energy. The mixed flow impeller has intermediate characteristics between the centrifugal impeller and the axial flow impeller. Note that “loading” means giving input energy, and if the flow rate is constant, the load is expressed as a lift when the impeller is used in a pump, and when it is used in a turbine. Is represented as a head and, when used in a blower, as a pressure.

  In the present invention, since the second impeller is a centrifugal impeller, the magnitude of the load applied to the second impeller is made larger than that of the axial-flow impeller having the same diameter as that of the prior art. As a result, the fluid energy that can be recovered by the second impeller while maintaining a small size can be increased.

  Further, in the counter-rotating impeller, it is known that the load applied to the first and second impellers needs to be substantially uniform in order to reduce friction loss and achieve high efficiency. It has been. In the contra-rotating impeller of the present invention, since the centrifugal impeller is used as the second impeller, the first impeller can be loaded with a load approximately equal to the centrifugal impeller. It is necessary to.

  When each impeller has the same diameter, fluid flow rate, and rotational speed, the magnitude of the load that can be applied to the axial flow impeller is smaller than that of the centrifugal impeller. Moreover, the magnitude | size of the load which can be applied to a mixed flow type impeller is a medium magnitude | size larger than an axial flow type impeller and smaller than a centrifugal impeller. In addition, the magnitude of the load that can be applied to the first impeller includes the magnitude of the load that can be applied to the axial flow type impeller and the magnitude of the load that can be applied to the mixed flow type impeller. It is sum.

  For this reason, in this invention, the magnitude | size of the load which can be applied to a 1st impeller by making the 1st impeller into the composite type impeller which combined the axial flow type and the mixed flow type is used. The load that can be applied to the second impeller is approximately equal to the magnitude of the load. Therefore, the friction loss at the second impeller outlet can be reduced, and the efficiency becomes high.

  Furthermore, since it is possible to increase the magnitude of the load applied to the first impeller, even if the diameter is the same as that of the small axial flow impeller of the prior art, as a result, the first impeller The fluid energy recoverable by the vehicle can be increased.

  As described above, according to the present invention, the recoverable fluid energy increases in each of the first and second impellers, so that the recoverable energy can be increased while maintaining a small size.

  The counter-rotating impeller of the present invention can also be used as an impeller for a pump or a blower. In this case, the flow of the fluid is opposite to that of the impeller for a water wheel or a windmill, and the second impeller is moved to the second for the water wheel or the windmill by an energy input means such as an electric motor connected to the second impeller. By rotating in a direction opposite to the rotation direction of the impeller, a fluid such as a liquid or a gas obtains energy from the second impeller and flows toward the first impeller. By rotating the first impeller in the opposite direction to the second impeller by energy input means such as an electric motor connected to the first impeller, the fluid obtains energy from the first impeller and Outflow from 1 impeller. Thereby, high energy, such as a high pressure and a high head, can be given to the flowing-out fluid.

  According to a preferred embodiment, the first impeller includes a hub, and a plurality of blades spirally provided on the outer peripheral surface of the hub with respect to the axial direction of the hub. The axial flow impeller includes a cylindrical portion having a constant diameter over the entire length, and a reduced diameter portion which configures the diagonal flow impeller and decreases in diameter toward the end.

  According to a preferred embodiment, each blade of the first impeller protrudes on the outer periphery of the second impeller.

  Another aspect of the present invention is a fluid machine including any of the counter-rotating impeller described above and a cylindrical casing that accommodates the counter-rotating impeller.

  The fluid machine may further include a cylindrical body fixed in the casing and rotatably supporting the first and second impellers in the casing.

  According to a preferred embodiment, the electric rotating machine further includes a rotating electric machine housed in the cylindrical body, and the rotating shaft of the rotating electric machine is connected coaxially with the shafts of the first and second impellers.

The fluid machine is used as, for example, a water wheel, a windmill, a pump, or a blower.
When the fluid machine is used as a water wheel, the fluid is water or liquid, and when the fluid is input to the first impeller, the first impeller rotates by obtaining energy from the fluid. A generator is connected to the first impeller, and the rotor of the generator is rotated by the first impeller to generate power. The fluid exits the first impeller and flows into the second impeller, and the second impeller obtains energy from the fluid and rotates in the opposite direction to the first impeller. A generator is connected to the second impeller, and the rotor of the generator rotates by the second impeller to generate electric power. The fluid flows out of the second impeller. When the fluid machine is used as a windmill, the fluid is air or gas, and the first impeller and the second impeller obtain energy from the fluid and rotate to generate electric power as in the case of the water wheel.

  When the fluid machine is used as a pump, the fluid obtains energy from the second impeller and rotates toward the first impeller by rotating the second impeller by an electric motor connected to the second impeller. Flowing. The fluid is water or liquid. The first impeller is connected to an electric motor, and the electric motor rotates the first impeller in the opposite direction to the second impeller, so that the fluid obtains energy from the first impeller and the first impeller Outflow from impeller. When the fluid machine is used as a blower, the fluid is air or gas, and air is blown by obtaining energy from the first impeller and the second impeller as in the case of the pump.

  According to the present invention, it is possible to provide a counter-rotating impeller and a fluid machine that are small and have large recoverable energy.

It is sectional drawing of the fluid machine which concerns on one Embodiment of this invention. (A) of a 1st impeller is the front view seen from the exit side, (B) is a perspective view. (A) of a 2nd impeller is the front view seen from the exit side, (B) is a perspective view. It is a meridian view of a fluid machine. (A) is a meridional view of a first impeller, and (B) is a meridional view of a second impeller. It is a meridional view showing another example of the fluid machine. It is a meridional view showing another example of the fluid machine.

  Embodiments of the present invention will be described with reference to the drawings. In the following description, an example in which a fluid machine is used as the water wheel 10 is shown, and a side where fluid is input to the water wheel 10 is referred to as an inlet side or an upstream side, and a side where fluid is output is referred to as an outlet side or a downstream side. Water, which is a fluid, flows in the direction from the first impeller 20 toward the second impeller 30 (the direction from left to right in FIG. 1 and the direction of arrow A). In the drawings, the generators 64, 74, 84, and 85 are shown in a simplified manner.

  1 to 5 show a counter-rotating impeller 40 and a water wheel 10 according to an embodiment of the present invention. As shown in FIG. 1, the water wheel 10 includes a counter-rotating impeller 40, a cylindrical casing 50 that accommodates the counter-rotating impeller 40 therein, and a fixed casing in the casing 50. The first and second cylindrical bodies 60 and 70 are arranged coaxially with the two impellers 20 and 30 and rotatably support the first and second impellers 20 and 30. Yes. In FIG. 1, the casing 50 is shown in cross section.

  The counter-rotating impeller 40 includes first and second impellers 20 and 30 arranged coaxially. The first impeller 20 and the axial flow impeller 21 aligned in the axial direction and the diagonal flow The second impeller 30 is a centrifugal impeller that rotates in a direction opposite to the rotation direction of the first impeller 20, and is located at a position continuous with the mixed flow impeller 22. Be placed.

  As shown in FIGS. 2 and 4, the first impeller 20 includes a hub 23 and a plurality of blades 24 spirally provided on the outer peripheral surface of the hub 23 with respect to the axial direction of the hub 23. ing. The hub 23 includes a cylindrical portion 25 having a constant diameter over the entire length, and a reduced diameter portion 26 that is continuous with the cylindrical portion 25 and decreases in diameter toward the end portion. A reduced diameter portion 26 is disposed on the outlet side. The blades 24 are arranged on the outer peripheral surface of the hub 23 at equal intervals in the circumferential direction. In this embodiment, the blades 24 receive a force from the fluid flowing from the upstream side and are counterclockwise when viewed from the inlet side (arrow B in FIG. 1). The blades 24 are provided so that the first impeller 20 rotates in the direction). The blade 24 has a protruding end portion 27 that protrudes from the outlet side end of the hub 23, and the protruding end portion 27 covers the outer periphery of the second impeller 30. An axial-flow impeller 21 is configured by the cylindrical portion 25 of the hub 23 and the portion provided on the cylindrical portion 25 of the blade 24, and is provided on the reduced diameter portion 26 of the hub 23 and the reduced diameter portion 26 of the blade 24. The mixed flow impeller 22 is constituted by the projecting portion and the protruding end portion 27.

  In this embodiment, six blades 24 are provided, the diameter on the inlet side of the first impeller 20 (also referred to as “inlet tip diameter”) DF1 is 90 mm, and the diameter on the inlet side of the hub 23 (also referred to as “inlet hub diameter”). DF2 is 60 mm, the diameter of the outlet side of the hub 23 (also referred to as “outlet outer diameter”) DF3 is 54 mm, the axial length BF of the hub 23 is 51 mm, and the axial length BF1 of the cylindrical portion 25 is 41 mm, the axial length BF2 of the reduced diameter portion 26 is 10 mm, and the protruding length 27 (also referred to as “outlet blade height”) BF3 of the blade 24 is 8.7 mm. It is not something.

  The second impeller 30 includes a disk-shaped main plate 32, a hub 33 provided in the central portion on one surface of the main plate 32, and a plurality of second impellers 30 erected around the hub 33 at equal intervals in the circumferential direction. Blades 34 are provided. In the present embodiment, the blade 34 is provided so that the second impeller 30 rotates in a clockwise direction (opposite to the arrow B in FIG. 1) when viewed from the inlet side by receiving a force from the fluid flowing from the upstream side. Yes. Each blade 34 is substantially L-shaped in the meridional view of FIG. 4 and FIG. 5B, and an L-shaped piece 34 a is connected to the main plate 32, and the other piece 34 b is connected to the hub 33. The second impeller 30 is arranged such that the main plate 32 is on the inlet side, the hub 33 is on the outlet side, the L-shaped piece 34a of the blade 34 is on the inlet side, and the other piece 34b is on the outlet side. The diameter DR1 of the impeller 30 is smaller than the diameter DF3 on the outlet side of the hub 23 of the first impeller 20. The protruding end portion 27 of the blade 24 of the first impeller 20 covers the entire length BR2 in the axial direction of the piece 34a of the blade 34, or covers the middle partway.

  In this embodiment, seven blades 34 are provided, the diameter of the second impeller 30, that is, the diameter of the main plate 32 (also referred to as “input chip diameter”) DR1 is 50 mm, and the diameter on the outlet side of the hub 33 (“exit hub”). DR2 is also 14 mm, the diameter of the outlet side of the second impeller 30 (also referred to as “outlet outer diameter”) DR3 is 34 mm, the total axial length BR of the second impeller 30 is 20 mm, and the blade 34 The axial length (also referred to as “entrance blade height”) BR2 of the piece 34a is 8.7 mm, and the thickness BR1 of the main plate 32 is 1 mm, but is not limited thereto.

  The shape of the blades 24 and 34 of the first and second impellers 20 and 30, the mounting angle of the blades 24 and 34 to the hubs 23 and 33, and the various dimensions described above are the first and second impellers. The load applied to 20 and 30 is approximately equal, and is appropriately set so as to achieve high efficiency.

  The first cylindrical body 60 is disposed on the upstream side of the first impeller 20. The first cylindrical body 60 is formed by forming a guide portion 62 having a tapered tip at the inlet side of the cylindrical portion 61. In the present embodiment, the guide portion 62 has a conical shape and a tip having a flat shape, but the tip may be sharp or rounded. The diameter of the cylindrical portion 61 of the first cylindrical body 60 is substantially equal to the diameter DF2 on the inlet side of the hub 23 of the first impeller 20. The first tubular body 60 is fixed to the inner wall of the casing 50 by spokes 63 provided at equal intervals in the circumferential direction on the outer peripheral surface of the first tubular body 60. A generator 64 is accommodated coaxially with the first impeller 20 in the first cylindrical body 60, and a shaft 23 a provided on the hub 23 of the first impeller 20 on the rotating shaft of the generator 64. Are connected by coupling or the like. As a result, the first impeller 20 is rotatably supported in the casing 50. An electric wire (not shown) connected to the generator 64 is drawn out of the casing 50 through an opening (not shown) provided in the casing 50 through the inside of the first tubular body 60 and the spoke 63. .

  The second cylindrical body 70 is disposed on the downstream side of the second impeller 30. The second cylindrical body 70 is cylindrical and has a diameter substantially equal to the diameter DR2 on the outlet side of the hub 33. The second cylindrical body 70 is fixed to the inner wall of the casing 50 by spokes 73 provided at equal intervals in the circumferential direction on the outer peripheral surface of the second cylindrical body 70. A generator 74 is accommodated coaxially with the second impeller 30 in the second cylindrical body 70, and a shaft 33 a provided on the hub 33 of the second impeller 30 on the rotating shaft of the generator 74. Are connected by coupling or the like. As a result, the second impeller 30 is rotatably supported in the casing 50. An electric wire (not shown) connected to the generator 74 is drawn outside through an opening (not shown) provided in the casing 50 through the inside of the second cylindrical body 70 and the spoke 73.

  The casing 50 can accommodate the wide-diameter portion 51 that can accommodate the first impeller 20 and the first tubular body 60, the second impeller 30 and the second tubular body 70, and the wide-diameter portion 51. And a small-diameter portion 52 having a smaller diameter than the portion 51. Both ends of the casing 50 are open, and the openings 50a and 50b serve as fluid inlets or outlets. In the present embodiment, the diameter of the wide diameter portion 51 is slightly larger than the diameter DF1 on the inlet side of the first impeller 20, and the diameter of the small diameter portion 52 is slightly larger than the diameter DR3 on the outlet side of the second impeller 30. Is set to be large. As a result, the fluid flowing through the first and second impellers 20 and 30 is prevented from leaking radially outward from the first and second impellers 20 and 30, and energy loss is reduced.

  Further, the wide diameter portion 51 has a shape along the outer shape of the first impeller 20 with the diameter of the outlet portion 51a continuously decreasing toward the outlet side. As a result, the direction in which the fluid flows changes gradually, and energy loss is reduced.

Operations of the counter rotating impeller 40 and the water wheel 10 according to the above embodiment will be described.
The water wheel is an in-line type, and a water pipe 11 such as a hose is attached to the opening 50a on the inlet side of the casing 50 as shown in FIG. In addition, without attaching the water pipe 11 to the water wheel, the water wheel 10 is set so that the opening 50a on the inlet side of the casing 50 faces the upstream side in a fluid such as a river with the openings at both ends of the casing 50 opened. It may be immersed.

  When water flows from the opening 50a on the inlet side of the casing 50, the water spreads along the outer surface of the guide portion 62 of the first cylindrical body 60 (arrow a1 in FIG. 4). The flow is rectified so as to flow in the axial direction outside the cylindrical portion 61 (arrow a2 in FIG. 4). Since the diameter of the cylindrical portion 61 of the first cylindrical body 60 and the diameter DF2 on the inlet side of the hub 23 of the first impeller 20 are substantially equal, water flows straight in the axial direction and the first impeller 20 It flows into the axial flow type impeller 21.

  When water flows into the first impeller 20 in the axial direction (arrow b1 in FIG. 4), a pressure difference is generated between the front and back surfaces of each blade 24 of the first impeller 20 (a pressure surface and a suction surface are formed). As a result, lift is generated, and the first impeller 20 rotates. Water flows into the mixed flow impeller 22, the flow is bent inward in the radial direction (arrow b2 in FIG. 4), and flows out of the mixed flow impeller 22.

  Due to the rotation of the first impeller 20, the rotating shaft of the generator 64 provided in the first cylindrical body 60 rotates to generate power. The generated electric power is sent to the outside of the water wheel by an electric wire passed through the first cylindrical body 60 and the spoke 63, and used for charging the storage battery, lighting, and the like.

  When water from the first impeller 20 flows radially inward into the second impeller 30 (arrow c1 in FIG. 4), pressure is applied to the front and back surfaces of each blade 34 of the second impeller 30. A difference arises, lift is generated, and the first impeller 20 rotates in the opposite direction. The water is bent in the axial direction (arrow c2 in FIG. 4) and flows out from the second impeller 30.

  Due to the rotation of the second impeller 30, the rotating shaft of the generator 74 provided in the second cylindrical body 70 rotates to generate power. The generated electric power is sent to the outside of the water wheel by an electric wire passed through the second cylindrical body 70 and the spoke 73 and used for charging the storage battery, lighting, and the like.

  According to said embodiment, since the centrifugal impeller is used for the 2nd impeller 30, compared with the axial flow type impeller of the same diameter of a prior art, the load applied to the 2nd impeller 30 As a result, the fluid energy that can be recovered by the second impeller 30 while maintaining a small size can be increased.

  Further, the first impeller 20 in the counter-rotating impeller 40 is obtained by making the first impeller 20 a composite impeller in which the axial flow impeller 21 and the mixed flow impeller 22 are combined. The load that can be applied to the second impeller 30 can be made equal, friction loss at the second impeller outlet can be reduced, and high efficiency can be achieved.

  Furthermore, since the magnitude of the load applied to the first impeller 20 can be increased, even if the diameter is the same as that of the small axial flow impeller of the prior art, as a result The fluid energy that can be recovered by the impeller 20 can be increased.

  As described above, according to the present invention, the fluid energy that can be recovered in each of the first and second impellers 20 and 30 increases, so that the energy that can be recovered can be increased while maintaining the small size.

  Further, the reduced diameter portion 26 of the hub 23 constituting the mixed flow impeller 22 of the first impeller 20 is provided continuously from the cylindrical portion 25 of the hub 23 constituting the axial flow impeller 21. Therefore, water flows smoothly in the axial direction from the axial flow type impeller 21 to the mixed flow type impeller 22, and friction loss is reduced.

Further, in the mixed flow type impeller 22 of the first impeller 20, the diameter of the hub 23 is reduced toward the outlet side, so that the water flowing direction is gently bent from the axial direction to the radial inward direction. And friction loss can be reduced.
In addition, each blade 24 of the first impeller 20 includes a protruding end portion 27 that protrudes to the outer periphery of the second impeller 30, so that the water flowing direction can be effectively bent radially inward. Water can be sent to the second impeller 30, and friction loss can be reduced.

  Further, when the fluid is directly input to the first impeller 20 without the first cylindrical body 60, the fluid hits the end surface of the hub 23 of the first impeller 20 and is directed radially outward. Since the direction is bent in the axial direction by being bent and then hitting the casing 50, it becomes difficult for the fluid to flow into the root side of the blade 24, or the flow of the fluid flowing into the first impeller 20 is biased, resulting in energy loss. growing. On the other hand, according to the above-described embodiment, the first cylindrical body 60 is disposed on the upstream side of the first impeller 20, and the input fluid is connected to the guide portion 62 of the first cylindrical body 60. Since it is rectified in the axial direction by the cylindrical portion 61 and input to the first impeller 20, an uneven flow of fluid is prevented and friction loss is small.

FIG. 6 shows another embodiment of the present invention.
A concave portion 20 a into which a cylindrical third cylindrical body 80 is fitted coaxially with the first impeller 20 is formed on the outlet side end face 23 b of the hub 23 of the first impeller 20. The third cylindrical body 80 is fixed to the inner wall of the casing 50 by a plurality of spokes 83 extending in the axial direction from the outlet side end face 80b and arranged at equal intervals in the circumferential direction. The spoke 83 is provided between the protruding end portion 27 of the first impeller 20 and the second impeller 30 and at a position that does not hinder the rotation of the first impeller 20 and the second impeller 30. It has been. A generator 84 is accommodated coaxially with the second impeller 30 in the third cylindrical body 80, and a shaft 33 a provided on the hub 33 of the second impeller 30 on the rotating shaft of the generator 84. Are connected by coupling or the like. The second impeller 30 is rotatably supported in the casing 50 by the third cylindrical body 80.

According to said structure, since the 3rd cylindrical body 80 which pivotally supports the 2nd impeller 30 is arrange | positioned in the 1st impeller 20, the water turbine 10 which is a fluid machine can be reduced in size.
Since other configurations are the same as those in the embodiment of FIG. 1, the corresponding portions are denoted by the same reference numerals and description thereof is omitted.

FIG. 7 shows another embodiment of the present invention.
A recessed portion 20 a into which a cylindrical third tubular body 80 is fitted coaxially with the first impeller 20 is formed on the outlet side end surface 23 b of the hub 23 of the first impeller 20. The third cylindrical body 80 is fixed to the inner wall of the casing 50 by spokes 83 extending in the axial direction from the outlet side end face 80b. The spoke 83 is provided between the protruding end portion 27 of the first impeller 20 and the second impeller 30 and at a position that does not hinder the rotation of the first impeller 20 and the second impeller 30. It has been. A second generator 84 is accommodated coaxially with the second impeller 30 on the outlet side in the third cylindrical body 80, and the second impeller 30 is disposed on the rotating shaft of the second generator 84. A shaft 33a provided on the hub 33 is coupled by a coupling or the like. A first generator 85 is accommodated coaxially with the first impeller 20 on the inlet side in the third cylindrical body 80, and the first impeller 20 is mounted on the rotating shaft of the first generator 85. A shaft 23a provided on the hub 23 is coupled by a coupling or the like. The shaft 23a of the first impeller 20 protrudes from the bottom of the recess 20a. The first and second impellers 20 and 30 can be rotatably supported in the casing 50 by the third cylindrical body 80.

The hub 23 of the first impeller 20 has a cylindrical portion 25 that is longer in the axial direction toward the inlet side than the embodiment of FIG. 1, and a guide portion 23 d whose tip is tapered toward the inlet side of the cylindrical portion 25. Is formed. Thereby, the input fluid is rectified in the axial direction.
Since the 3rd cylindrical body 80 which pivotally supports the 2nd impeller 30 is arrange | positioned in the 1st impeller 20, the water turbine 10 which is a fluid machine can be reduced in size.
Since other configurations are the same as those in the embodiment of FIG. 1, the corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning of this invention.

  In the above embodiment, the axial-flow impeller 21 and the mixed-flow impeller 22 of the first impeller 20 are integrally formed, but as a so-called multistage type that is separately formed and coaxially connected. It may be formed.

The fluid machine is not limited to the water turbine 10 and is used as, for example, a windmill, a pump, or a blower.
When the fluid machine is used as a windmill, the fluid is air or gas, and the first impeller 20 and the second impeller 30 rotate by obtaining energy from the fluid as in the case of the turbine, Electric power is generated by the generators 64 and 74 connected to the car 20 and the second impeller 30.

  When the fluid machine is used as a pump, the generators 64, 74, 84, and 85 are replaced with electric motors in the above embodiment. By rotating the second impeller 30 in the opposite direction to the second impeller 30 in the case of a water turbine by an electric motor connected to the second impeller 30, the fluid receives energy from the second impeller 30. And flows toward the first impeller 20. The fluid is water or liquid. The first impeller 20 is connected to an electric motor, and the electric motor rotates the first impeller 20 in the opposite direction to the second impeller 30, so that fluid obtains energy from the first impeller 20. And flows out from the first impeller 20. The fluid is given high energy. When the fluid machine is used as a blower, the fluid is air or gas, and air is blown by obtaining energy from the first impeller 20 and the second impeller 30 as in the case of the pump.

  When the fluid machine is used as a windmill, pump, or blower, the shape and orientation of the blades 24 and 34 of the first and second impellers 20 and 30, the mounting angle of the blades 24 and 34 to the hubs 23 and 33, various types The dimensions are appropriately set so that they can be driven efficiently according to the application of the fluid machine.

10 Water wheel (fluid machine)
20 first impeller 30 second impeller 40 counter-rotating impeller 21 axial flow impeller 22 diagonal flow impeller 23 hub 24 blade 25 cylindrical portion 26 reduced diameter portion 27 projecting end portion 50 casing 60 , 70, 80 First to third cylindrical bodies 64, 74, 84 Generator (rotary electric machine)

Claims (6)

Consists of first and second impellers arranged coaxially,
The first impeller has an axial flow impeller and a mixed flow impeller arranged in the axial direction,
The second impeller is a centrifugal impeller that rotates in a direction opposite to the rotation direction of the first impeller, and is a counter-rotating impeller disposed at a position connected to the mixed flow impeller. . The first impeller includes a hub and a plurality of blades spirally provided on the outer peripheral surface of the hub with respect to the axial direction of the hub,
The hub is
The axial flow type impeller is configured, and a cylindrical portion having a constant diameter over the entire length;
The counter-rotating impeller according to claim 1, further comprising a reduced diameter portion that constitutes the mixed flow impeller and has a diameter that decreases toward an end portion.   3. The counter-rotating impeller according to claim 2, wherein each blade of the first impeller projects on an outer periphery of the second impeller. A counter-rotating impeller according to any one of claims 1 to 3,
A fluid machine comprising a cylindrical casing that houses the counter-rotating impeller.   The fluid machine according to claim 4, further comprising a cylindrical body fixed in the casing and rotatably supporting each of the first and second impellers in the casing. Further comprising a rotating electrical machine housed in the cylindrical body,
The fluid machine according to claim 5, wherein a rotating shaft of the rotating electrical machine is connected coaxially with the shafts of the first and second impellers.