JP2012202260A - Impeller and turbo machine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impeller including a blade structure to avoid lowering of performance of a turbo machine and to enhance energy conversion efficiency.SOLUTION: In this impeller 1, a plurality of blades 6 extending to a rotating direction rear side toward the radial direction outside from a rotary shaft center are arranged at intervals in a peripheral direction, and a main flow passage 15 in which a main flow W flows is formed between the blades 6 adjacent to each other in the peripheral direction toward the radial direction outside. The impeller 1 includes; an inflow hole 8 opened in each of the blades 6; an outflow hole 9 opened in a portion at the radial direction outside of the inflow hole 8 in the blade 6; and a boosting chamber 14 which is formed in the blade 6, is connected to the inflow hole 8 and the outflow hole 9 and has larger cross-sectional area orthogonal to a flowing direction of auxiliary fluid W2 flowing at the inside than that of at least one of the inflow hole 8 and the outflow hole 9.

Description

  The present invention relates to an impeller in a turbomachine such as a pump that converts mechanical energy into fluid pressure and kinetic energy.

  2. Description of the Related Art Conventionally, a turbo machine such as a pump that boosts a fluid using mechanical energy and imparts kinetic energy to the fluid, or a turbine that extracts the pressure or kinetic energy of the fluid as mechanical energy is known. There are various types of turbomachines, for example, an axial flow type in which fluid flows in the axial direction of the turbomachine, a diagonal flow type in which fluid flows in an oblique direction with respect to the axis, or a direction orthogonal to the axis. For example, a centrifugal type in which a fluid flows in the direction in which the fluid flows is used.

  Among the above turbomachines, in particular, impellers installed in pumps and water turbines cause cavitation near the impeller blades during operation, causing erosion near the blades, leading to performance degradation of the pump and water turbine. There was a case. On the other hand, for example, Patent Document 1 discloses a water turbine provided with an impeller that suppresses the occurrence of cavitation by providing a through hole that communicates a suction surface side and a pressure surface side of a blade.

JP-A-5-99115

  However, in the conventional impeller, means for solving the problem of boundary layer separation on the suction surface side of the blade and the occurrence of a fluid stall region at the outer peripheral edge of the blade, which are other factors that cause the performance of the turbomachine to deteriorate. Is not established.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an impeller having a blade structure that avoids performance degradation of the turbomachine and increases energy conversion efficiency, and a turbomachine equipped with the impeller. To do.

In order to solve the above problems, the present invention employs the following means.
That is, in the impeller according to the present invention, a plurality of blades extending rearward in the rotational direction from the center of the rotational axis toward the radially outer side are arranged at intervals in the circumferential direction, and adjacent to each other in the circumferential direction toward the radially outer side. In the impeller in which a fluid flow path is formed, an inflow hole opening in the wing, an outflow hole opening in a portion radially outside the inflow hole in the wing, and an inside of the wing are formed. A pressure increasing chamber connected to the inflow hole and the outflow hole and having a larger cross-sectional area perpendicular to the flow direction of the fluid flowing through the inside than at least one of the inflow hole and the outflow hole. Features.

  In such an impeller, a part of the fluid introduced into the main flow channel of the impeller is taken into the pressure increasing chamber through the inflow hole. In the pressurizing chamber, the fluid is decelerated due to the difference in cross-sectional area between the inflow hole and the outflow hole, and the pressure is increased by the centrifugal force acting on the fluid itself, and is discharged from the outflow hole. As a result, boundary layer separation generated on the blade and fluid stall generated at the outer peripheral edge of the blade are suppressed.

  The inflow hole is preferably opened on the suction surface side of the blade.

  The boundary layer is easy to develop because the rear side of the blade rotation direction is the suction side. Therefore, more boundary layer can be sucked from the inflow hole opened to the suction surface side, and the effect of stabilizing the flow is easily obtained. Therefore, by providing an impeller having such a blade structure, a decrease in fluid flow performance is avoided, and energy conversion efficiency during turbomachine operation is improved.

  Furthermore, it is preferable that the outflow hole is opened on the suction surface side of the blade.

  When the fluid whose pressure has been increased in the pressurizing chamber is discharged from the outflow hole to the suction surface side of the blade, the boundary layer in the vicinity of the outflow hole opening can be accelerated and separation can be suppressed, and the flow can be stabilized. Therefore, by providing an impeller having such a blade structure, a decrease in fluid flow performance is avoided, and energy conversion efficiency during operation of the turbomachine is improved.

  Moreover, the said outflow hole may open to the outer peripheral edge part of the said wing | blade here.

  The fluid whose pressure has been increased in the pressurizing chamber is discharged to the outer peripheral end of the blade, which is the stall region of the main flow of the fluid, whereby the fluid is accelerated in the stall region. Therefore, by providing an impeller having such a blade structure, energy loss due to fluid stall is suppressed, and energy conversion efficiency during turbomachine operation is improved.

  Further, the inflow hole may open to the pressure surface side of the blade.

  Although the possibility of boundary layer development is low on the pressure surface side in front of the blade rotation direction, the force acts on the pressure surface side in the direction in which the fluid is pressed against the blade. Is captured. For this reason, more fluid is increased in pressure in the pressurizing chamber, and the fluid is discharged from the outflow hole, thereby suppressing boundary layer separation and accelerating the fluid in the fluid stall region. Therefore, by providing an impeller having such a blade structure, a decrease in fluid flow performance is avoided, and energy conversion efficiency during operation is improved.

  In the state where the inflow hole is opened on the pressure surface side of the blade, the outflow hole is preferably opened on the suction surface side of the blade.

  The fluid that is taken in from the pressure side opening of the blade and increased in pressure in the pressurization chamber is discharged to the suction surface side of the blade, thereby accelerating the boundary layer near the outflow hole opening and suppressing boundary layer separation. Is stabilized. Therefore, by providing an impeller having such a blade structure, a decrease in fluid flow performance is avoided, and energy conversion efficiency during turbomachine operation is improved.

  Further, the outflow hole may be opened at the outer peripheral end of the blade in a state where the inflow hole is opened to the pressure surface side of the blade.

  Energy loss in the stall region of the flow can be prevented by discharging the fluid taken in from the opening on the pressure surface side of the blade and increased in pressure in the pressurizing chamber to the outer peripheral end of the blade. Therefore, by providing the impeller having such a blade structure, the performance degradation of the turbomachine is avoided and the energy conversion efficiency during operation is improved.

  Moreover, in a turbo machine, it is preferable to provide one of the above impellers.

  By providing the turbomachine with the impeller capable of suppressing the boundary layer separation occurring in the blade and the stall of the fluid generated at the outer peripheral edge of the blade, the performance degradation of the turbomachine is avoided, and the energy during operation Conversion efficiency is improved.

  According to the impeller and turbomachine of the present invention, separation due to the development of the boundary layer around the blade can be suppressed, the fluid can flow smoothly, and energy loss can be avoided in the fluid stall region. Therefore, a decrease in fluid flow performance is avoided, energy conversion efficiency during operation of the turbomachine can be improved, leading to cost reduction effects and improved product reliability.

It is a figure showing the whole impeller concerning a first embodiment of the present invention. It is a figure which expands and shows the wing | blade part of the impeller which concerns on 1st embodiment of this invention. It is sectional drawing of the blade | wing of the impeller which concerns on 1st embodiment of this invention, and is a figure which shows the inflow hole, outflow hole, and pressure | voltage rise chamber inside a blade | wing. It is sectional drawing of the blade | wing of the impeller which concerns on 2nd embodiment of this invention, and is a figure which shows the inflow hole, outflow hole, and pressure | voltage rise chamber inside a blade | wing. It is sectional drawing of the blade | wing of the impeller which concerns on 3rd embodiment of this invention, and is a figure which shows the inflow hole, outflow hole, and pressure | voltage rise chamber inside a blade | wing. It is sectional drawing of the blade | wing of the impeller which concerns on 4th embodiment of this invention, and is a figure which shows the inflow hole, outflow hole, and pressure | voltage rise chamber inside a blade | wing.

Hereinafter, an impeller 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
The impeller 1 is installed in a centrifugal pump (turbo machine) that introduces the main fluid W into the impeller 1 and causes the main fluid W to flow out after increasing the pressure and kinetic energy of the main fluid W.
The impeller 1 includes a disk 2, a blade 6, a cover 3, and an inflow hole 8, an outflow hole 9, and a boosting chamber 14 formed inside the wing 6.

  The disk 2 is a member extending in a disc shape with the axis O as the center, and has a first fitting hole 4 penetrating in the direction of the axis O at the center. By inserting a rotating shaft or the like (not shown) into the first fitting hole 4, the disk 2 rotates integrally with the rotating shaft or the like.

  A plurality of blades 6 (seven in this embodiment) are provided on one end face of the disk 2 facing the one side in the axis O direction with a circumferential interval. The blade 6 protrudes from one end surface of the disk 2 and extends curvedly toward the rear side in the rotational direction of the disk 2 toward the outer side in the radial direction. Further, a main flow channel 15 through which the main fluid W flows is between adjacent blades 6.

  Here, in the present embodiment, the blade 6 has a curved shape, but it only needs to extend rearward in the rotational direction about the axis O toward the radially outer side. Therefore, it is not limited to the curved shape in this embodiment.

  The cover 3 is a member provided so as to cover the plurality of blades 6 from one side in the axis O direction. The cover 3 has a disk shape centered on the axis O, and specifically has an umbrella shape that gradually decreases in diameter toward one side in the direction of the axis O. Further, the edge on the one side in the axis O direction of the blade 6 and the surface facing the other side in the cover axis O direction are fixed integrally. Further, a second fitting hole 5 penetrating in the axis O direction is formed in the center of the cover 3 in the same manner as the disk 2. In the impeller 1, the main fluid W is introduced into the inside through the second fitting hole 5, and a plurality of blades into which the main fluid W is introduced through the second fitting hole 5. A space 6 on the inner side in the radial direction is an introduction port 7.

  The inflow hole 8 has a first opening 10 formed on the suction surface side that is the rear side of the blade 6 in the rotation direction, and gradually forwards in the rotation direction of the impeller from the first opening 10 toward the radially outer side of the blade 6. And a first auxiliary flow path 11 extending to the side.

  The outflow hole 9 has a second opening 12 formed radially outside the inflow hole 8 on the suction surface side behind the blade 6 in the rotation direction, and the inside of the blade 6 from the second opening 12 in the radial direction. The second auxiliary flow path 13 gradually extends forward in the rotational direction of the impeller as it goes inward.

  The pressurizing chamber 14 is a space inside the blade 6 that extends in the extending direction of the blade 6 so as to connect the first auxiliary channel 11 and the second auxiliary channel 13. The cross section in the direction orthogonal to the extending direction has a larger cross-sectional area than the cross section orthogonal to the extending direction of the first auxiliary channel 11 or the second auxiliary channel 13. In addition, although the pressure | voltage rise chamber 14 of this embodiment has comprised the substantially rectangular parallelepiped shape, you may comprise other shapes, such as a column shape, for example.

  When viewed from the direction of the axis O, the impeller 1 of the present embodiment rotates at an angular velocity ω counterclockwise around the axis O with the radius of the disk 2 as r. The main fluid W flowing from the introduction port 7 flows at a velocity V from the radially inner side to the outer side of the impeller 1 through the main flow channel 15 formed between the adjacent blades 6.

  When the main fluid W flows through the main flow channel 15, a part of the main fluid W is taken into the pressurizing chamber 14 from the suction surface side of the blade 6 through the inflow hole 8 as the auxiliary fluid W2. After being discharged to the outside of the blade 6 from the outflow hole 9 formed on the blade 6 suction surface side, the blade 6 merges with the main fluid W again.

Next, the operation of the impeller 1 configured as described above will be described.
The auxiliary fluid W2 introduced from the suction surface side of the blade 6 into the pressure increasing chamber 14 through the inflow hole 8 is increased in pressure by the centrifugal force acting on the auxiliary fluid W2 itself, and the suction surface of the blade 6 through the outflow hole 9. Vomited to the side. That is, the boundary layer developed on the suction surface side is sucked from the main fluid W and discharged to the main fluid W as the boosted auxiliary fluid W2, thereby accelerating the boundary layer and suppressing separation of the boundary layer to stabilize the boundary layer. Can be achieved.

Here, the pressure increase of the auxiliary fluid W2 is performed as follows.
When the auxiliary fluid W2 that is taken into the pressure increasing chamber 14 at the same speed V as the main fluid W and flows through the first auxiliary flow path 11 at the speed V flows into the pressure increasing chamber 14 from the first auxiliary flow path 11, The speed of the auxiliary fluid W2 itself is reduced by widening the area of the flow path cross section. Due to this deceleration, the centrifugal force exerted on the auxiliary fluid W2 in the pressure increasing chamber 14 increases, and the pressure of the auxiliary fluid W2 is increased.

Here, the rotational angular velocity ω of the impeller 1, the radius r of the disk 2, the rotational direction component v of the impeller 1 of the flow velocity V of the auxiliary fluid W 2, and the centrifugal force exerted on the fluid per unit in the pressurizing chamber 14. When F is the density of the main fluid W, that is, the density of the auxiliary fluid W2 is ρ, F = ρ (rω−v) ² / r for the auxiliary fluid W2 in the pressurizing chamber 14 Is established. Therefore, when the impeller 1 rotates at a constant angular velocity ω, the smaller v is, that is, the smaller the velocity V of the auxiliary fluid W2 in the pressure increasing chamber is, the larger the centrifugal force F acting on the auxiliary fluid W2 is. It shows that the pressure increasing effect on the auxiliary fluid W2 is improved.

  The impeller 1 having the blades 6 having the boosting chamber 14 can reduce the flow loss of the main fluid W due to the separation of the boundary layer, thereby improving the energy conversion efficiency during the centrifugal pump operation.

Next, with reference to FIG. 4, the impeller 1 of 2nd embodiment is demonstrated.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment, and detailed description is abbreviate | omitted.

  In the present embodiment, the inflow hole 8 having the first opening 10 on the suction surface side of the blade 6, the outflow hole 9 having the second opening 12 at the outer peripheral end of the blade 6, and the pressurizing chamber 14 in the blade 6. Is provided.

  The boundary layer developed on the suction surface side of the blade 6 is sucked from the inflow hole 8 and increased in pressure in the pressure increasing chamber 14 as the auxiliary fluid W2, and then to the outer peripheral end of the blade 6 through the outflow hole 9. It is discharged and merges with the main fluid W again.

  Therefore, the boundary layer is stabilized by sucking the boundary layer on the suction surface side, and at the same time, energy loss at the outer peripheral end portion of the blade 6 which is the stall region of the main fluid W can be suppressed. That is, by providing the impeller 1 of this embodiment, the performance of the centrifugal pump can be improved.

Next, with reference to FIG. 5, the impeller 1 of 3rd embodiment is demonstrated.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment, and detailed description is abbreviate | omitted.

  In the present embodiment, the inflow hole 8 having the first opening 10 on the pressure surface side that is forward of the blade 6 in the rotation direction, the outflow hole 9 having the second opening 12 on the suction surface side of the blade 6, and the inside of the blade 6. Pressure boosting chamber 14.

  By providing the inflow hole 8 on the pressure surface side of the blade 6, the pressure of the main fluid W acts in the pressing direction against the blade 6, so that more auxiliary fluid W <b> 2 is smoothly taken into the pressure increasing chamber 14. . Then, the auxiliary fluid W2 increased in pressure in the pressurizing chamber 14 is discharged to the negative pressure surface side of the blade 6 through the outflow hole 9.

  That is, a higher acceleration effect can be obtained with respect to the boundary layer developed on the suction surface side of the blade 6, and the flow loss of the main fluid W can be reduced due to separation of the boundary layer. Therefore, the impeller 1 of this embodiment can suppress the performance degradation due to the energy loss during the centrifugal pump operation.

Next, with reference to FIG. 6, the impeller 1 of 4th embodiment is demonstrated.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment, and detailed description is abbreviate | omitted.

  In the present embodiment, the inflow hole 8 having the first opening 10 on the pressure surface side that is the front of the blade 6 in the rotation direction, the outflow hole 9 having the second opening 12 at the outer peripheral end of the blade 6, and the blade 6. And an internal pressure chamber 14.

  From the first opening 10 of the inflow hole 8 on the pressure surface side of the blade 6, more auxiliary fluid W <b> 2 is taken into the pressurization chamber 14 and is pressurized in the pressurization chamber 14. The second opening 12 discharges to the stall region of the main fluid W at the outer peripheral end of the blade 6.

  By providing such an impeller 1, an effect of suppressing energy loss in the stall region can be obtained, and energy conversion efficiency during operation of the centrifugal pump can be improved.

  Although the embodiment of the present invention has been described in detail above, some design changes can be made without departing from the technical idea of the present invention.

  For example, if it is possible to control the boundary layer and the stall region of the main fluid W, the inflow hole 8 and the outflow hole 9 are directly connected without the pressurizing chamber 14, or a slit is provided instead of the hole. A form that is easy to process may be used.

  In the embodiment, an example of a centrifugal pump has been described as a turbo machine. However, the present invention is not limited to this, and the present invention may be applied to other turbo machines such as a compressor. In this case, the working fluid is not a liquid but a gas such as air or gas.

DESCRIPTION OF SYMBOLS 1 ... Impeller, 2 ... Disc, 3 ... Cover, 4 ... First fitting hole, 5 ... Second fitting hole, 6 ... Wing,
7 ... Inlet port, 8 ... Inflow hole, 9 ... Outflow hole, 10 ... First opening, 11 ... First auxiliary channel,
12 ... 2nd opening, 13 ... 2nd auxiliary flow path, 14 ... Pressure | voltage rise chamber, 15 ... Mainstream flow path, O ... Axis line,
W ... Main fluid, W2 ... Auxiliary fluid

Claims (8)

A plurality of blades extending rearward in the rotational direction from the center of the rotation axis toward the radially outer side are arranged at intervals in the circumferential direction, and a fluid flows between the blades adjacent in the circumferential direction toward the radially outer side. In the impeller where the road was formed,
An inflow hole opening in the wing;
An outflow hole that opens in a radially outer portion of the wing than the inflow hole;
A pressure increasing chamber formed inside the blade and connected to the inflow hole and the outflow hole and having a larger cross-sectional area perpendicular to the flow direction of the fluid flowing through the inside than at least one of the inflow hole and the outflow hole An impeller characterized by comprising:   The impeller according to claim 1, wherein the inflow hole is open to a suction surface side of the blade.   The impeller according to claim 2, wherein the outflow hole is open to a suction surface side of the blade.   The impeller according to claim 2, wherein the outflow hole is opened at an outer peripheral end of the blade.   The impeller according to claim 1, wherein the inflow hole opens on the pressure surface side of the blade.   The impeller according to claim 5, wherein the outflow hole is opened to a suction surface side of the blade.   The impeller according to claim 5, wherein the outflow hole opens at an outer peripheral end of the blade.   A turbomachine comprising the impeller according to any one of claims 1 to 7.

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