CN209892500U - Centrifugal pump blade capable of avoiding fluid stall - Google Patents

Abstract

The utility model discloses a can avoid fluid stall's centrifugal pump blade, including the blade body, the blade body is equipped with the mounting groove in its suction surface one side, is equipped with passive form fluidic device in the mounting groove, and passive form fluidic device includes the casing, is equipped with aqua storage tank and the confined cavity that communicates with the blade body is outer in the casing, and aqua storage tank and cavity are separated through an elastic film. The utility model has the advantages that: the deformation displacement generated by the elastic film continuously pumps the fluid on the surface of the blade, so that the blade can quickly adapt to the pressure change at the tail position of the suction surface, the unstable flow phenomena such as backflow, stall vortex and the like are prevented, and the overall stability of the centrifugal pump is improved; the passive jet device belongs to passive control, does not need external signals and energy injection, and can carry out real-time self-adaptation on an internal flow field when the centrifugal pump operates; the device has simple structure and low cost, and improves the overall stability of the centrifugal pump.

Description

Centrifugal pump blade capable of avoiding fluid stall

Technical Field

The utility model relates to a fluid machinery equipment technical field especially relates to a can avoid centrifugal pump blade of fluid stall.

Background

Due to the structural characteristics of large diffusion degree of the flow channel of the centrifugal pump and the like, when the centrifugal pump operates under the working condition of small flow, fluid is easy to flow and separate on the suction surface of the blade to form separation vortex, the separation vortex gradually develops into stall cluster, the stall cluster weakens the through-flow capacity of the flow channel, even causes the flow channel to be blocked in serious conditions, and the operation stability and efficiency of the pump are seriously influenced. At present, control research on the stall of the centrifugal pump mostly stays on the analysis of the stall phenomenon inside the centrifugal pump under a small-flow working condition and the analysis of the movement characteristic of a stall group, a better solution and a better result are not converted to reduce and control the stall phenomenon of the centrifugal pump, and the optimization and modification design effect on the centrifugal pump blades is not obvious.

For example, the chinese patent document entitled "a centrifugal pump impeller having high operation efficiency" discloses a centrifugal pump impeller having high operation efficiency, which is published by chinese patent document No. CN205744585U on the publication date 2016, 11, and 30. The impeller of the centrifugal pump is provided with the rectifying convex part on the back of the blade, and the rectifying convex part is arranged in the middle of the back of the blade or on one side of the middle of the back of the blade, which is close to the inlet of the blade. The geometrical parameters of the rectifying convex part are as follows: theta 1/phi is more than or equal to 0.25 and less than or equal to 0.55; (theta 2-theta 1)/phi is more than or equal to 0.24 and less than or equal to 0.40; delta/h is more than or equal to 0.25 and less than or equal to 0.95; in the formula: phi is the blade wrap angle; theta 1 is an included angle between the blade inlet and the starting point of the rectifying convex part; theta 2 is the included angle between the blade inlet and the terminal point of the rectifying convex part; h is the distance between the highest point of the rectifying convex part and the working surface of the blade at the corresponding position; delta-the distance between the back surface of the blade without the rectifying convex part and the working surface of the blade at the corresponding position, and the value positions of the distance h and the distance delta are the same. The disadvantages are that: 1. the optimization and modification design effect of the centrifugal pump blade is not obvious, the working principle is that the convex part is added to forcibly disturb the water flow in the centrifugal pump, the pressure of the water flow in the back pressure area of the blade in the centrifugal pump cannot be compensated, the kinetic energy of the water body can be reduced, and the power transfer of the centrifugal pump is reduced; 2. the structural parameters of the rectifying convex part are assisted and integrated with the blade, so that the manufacturing cost of the blade is increased.

It is therefore desirable to design a centrifugal pump blade that automatically adjusts the pressure at the surface of the blade to avoid stalling of the fluid.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the not enough of stall phenomenon appears easily in the backpressure district of overcoming centrifugal pump blade among the prior art, provides a can avoid fluid stall's centrifugal pump blade, and the pressure variation of adaptation suction surface afterbody position department that can be very fast prevents to form unstable flow phenomena such as backward flow and stall whirlpool, improves the holistic stability of centrifugal pump.

In order to achieve the above purpose, the present invention adopts the following technical solution.

The utility model provides a can avoid centrifugal pump blade of fluid stall, includes the blade body, and the blade body is equipped with the mounting groove in its suction surface one side, is equipped with passive form fluidic device in the mounting groove, and passive form fluidic device includes the casing, is equipped with the aqua storage tank and the confined cavity with the outer intercommunication of blade body in the casing, and aqua storage tank and cavity are separated through an elastic film.

When the centrifugal pump stably operates, the pressure outside the jet orifice and the pressure in the cavity are in a balanced state, when the pump operates under a low-flow working condition, unstable flow phenomena such as flow separation, backflow, stall vortex and the like are easily generated at the tail part of the suction surface of the blade of the centrifugal pump due to changes of an inflow angle, large divergence degree of a flow channel and the like, so that a low-pressure even negative-pressure area is formed, when the surface pressure of the blade begins to be reduced and the energy of a boundary layer is insufficient, the elastic film is displaced towards the jet orifice due to the pressure change, at the moment, fluid in the water storage tank flows towards the flow channel at a certain speed due to the reduction of the volume of the water storage tank, and the fluid with the speed increases the energy of the boundary layer, so that the fluid is not easy to generate flow separation at the tail end of the suction surface, and; when the surface pressure of the jet orifice is overlarge, fluid can be pressed into the water storage tank to enable the elastic film to generate displacement away from the jet orifice, a local high-pressure area formed at the tail part of the blade body is relieved, and therefore the fluid is not easy to generate backflow at the inlet position of the front end of the blade body due to the huge pressure difference of the inlet and the outlet of the impeller; the passive jet device is embedded in the blade body, the original shape of the blade body is not changed, the acting of the blade body is not influenced, and the stability of water flow in the centrifugal pump is improved.

Preferably, the chord length of the blade body bone line is L, the mounting groove is located 0.3 ~ 0.4.4L forward of the tail end of the blade body, the passive jet device is located in the mounting groove, when the centrifugal pump operates under a low-flow working condition, unstable flow phenomena such as flow separation, backflow, stall vortex and the like are caused to occur at the tail position of the suction surface of the blade easily due to the change of an inflow angle, the large diffusion degree of a flow channel and the like, a low-pressure or even negative-pressure area is formed, and the mounting groove is located at the position, so that the actual compensation effect of the passive jet device can be enhanced, and the stall of the flow in the centrifugal pump can be eliminated.

Preferably, the aqua storage tank is symmetrical structure, and the aqua storage tank includes four walls, and wherein a set of relative wall is parallel relative for equality in the aqua storage tank, thereby another relative wall of group draws close gradually from inside to outside in the aqua storage tank and makes the aqua storage tank form convergent spray tube shape, and the aqua storage tank is including the end of sealing a class and the jet orifice that are located its both ends, and the end of sealing a class is parallel with the jet orifice, and the jet orifice is located the suction surface of blade body, and elastic film's border and the end laminating of sealing a class. The wall surface of the water storage tank is in a tapered spray pipe shape, and the size of a jet orifice positioned on the suction surface of the blade body is the smallest size of the wall surface of the water storage tank, so that the shape of the surface of the blade is kept unchanged as far as possible under the condition that the acting of the blade is not influenced.

Preferably, the jet orifice is rectangular, the flow sealing end is rectangular, the width of the jet orifice is 0.0025 to 0.0075L, the width of the cavity is the same as that of the flow sealing end, and the width of the cavity is 0.1 to 0.15L. The structural strength of the blade body is guaranteed, and meanwhile the passive jet device is convenient to arrange in the installation groove.

Preferably, the shape of a generatrix of the wall surface of the water storage tank is an's' shape formed by overlapping two tangent circular arcs, the central angle of each circular arc is smaller than 90 degrees, and a tangent line at the jet opening is parallel to a tangent line at the flow sealing end. The tapered spray pipe is structurally optimized by combining the advantages of a streamline nozzle and a conical nozzle, the loss coefficient is reduced, the large flow rate coefficient is ensured, and the compensation capacity of the water storage tank for the local high-pressure area at the tail part of the blade body is improved.

Preferably, the elastic membrane is made of a silicone material. The pressure pulsation generated by vibration of a metal vibrating plate and a ceramic vibrating plate adopted by a conventional jet device can be reduced, and the overall stability of the passive jet device is improved.

Preferably, the housing is made of metal foil. The metal foil has good flexibility and can buffer pressure pulsation generated by vibration of the elastic film to a certain extent, so that the passive jet device and the blade can have a good coupling effect; the metal foil is made of metal with good extensibility by hammer forging or rolling, and has smooth surface and small resistance.

Preferably, the shape of the shell is a cuboid, a concave platform is arranged on one side of the jet opening of the water storage tank of the shell, a convex shoulder matched with the concave platform is arranged in the mounting groove, and the concave platform and the convex shoulder are fixed through a plurality of screws. The passive jet device is convenient to install and fix on the blade body.

The utility model discloses an useful part lies in: 1. the deformation displacement generated by the elastic film continuously pumps fluid on the surface of the blade, and the blade can quickly adapt to pressure change at the tail position of the suction surface, so that the original energy structure of the boundary layer is changed, the suction surface is not easy to flow and separate, unstable flow phenomena such as backflow, stall vortex and the like are prevented from being formed, and the overall stability of the centrifugal pump is improved; 2. the passive jet device belongs to passive control, does not need external signals and energy injection, and can carry out real-time self-adaptation on an internal flow field when the centrifugal pump operates; 3. the device has simple structure and low cost, and has quick response to the change of the fluid pressure and energy on the surface of the blade.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is an enlarged view at a in fig. 1.

Fig. 3 is a schematic structural view of the present invention applied to the whole impeller.

Fig. 4 is a schematic structural diagram of the passive fluidic device of the present invention.

In the figure: the suction surface 11 of the blade body 1 is mounted on the groove 111, the water storage groove 22 of the shell 21 of the passive jet device 2 is provided with a flow sealing end 221, a jet opening 222, a cavity 23, an elastic film 24, a concave platform 25, a screw 3 and the chord length L of the bone line of the blade body.

Detailed Description

The invention is further described with reference to the accompanying drawings and specific embodiments.

In fig. 1, 2 and 4, a centrifugal pump blade capable of avoiding fluid stall comprises a blade body 1, wherein the blade body 1 is provided with a mounting groove 111 on one side of a suction surface 11, a bone line is made on a section of a space blade at the middle position of the blade body 1, and the chord length of the bone line of the blade body 1 is L and the unit is centimeter; the mounting groove 111 is located 0.35L forward from the trailing end of the blade body 1. The passive jet device 2 is arranged in the mounting groove 111, the passive jet device 2 comprises a shell 21, the shell 21 is made of metal foil, and the thickness is determined according to specific conditions. The shell 21 is internally provided with a water storage tank 22 and a closed cavity 23 which are communicated with the outside of the blade body 1, and the water storage tank 22 and the cavity 23 are separated by an elastic film 24. The elastic membrane 24 is made of a silicone material. The end face width of the tail end of the blade body is C, and the unit is centimeter; the height of the cavity is 0.25C, and the depth of the water storage tank is 0.25C.

The water storage tank 22 has a symmetrical structure, and the water storage tank 22 includes four wall surfaces. One set of the opposite wall surfaces in the water storage tank 22 are parallel and opposite, and the other set of the opposite wall surfaces in the water storage tank 22 gradually draw together from the bottom of the tank to make the water storage tank 22 form a tapered nozzle shape. The water storage tank 22 comprises a flow blocking end 221 and a jet orifice 222 which are positioned at two ends of the water storage tank, the flow blocking end 221 is parallel to the jet orifice 222, the jet orifice 222 is positioned on the suction surface 11 of the blade body 1, and the edge of the elastic film 24 is attached to the flow blocking end 221. The generatrix of the wall surface of the water storage tank 22 is in an s shape formed by overlapping two tangent circular arcs, and the central angle of each circular arc is smaller than 90 degrees. The tangent at jet port 222 and the tangent at the flow-blocking end 221 are parallel. The shape of the flow sealing end 221 is rectangular, the shape of the jet orifice 222 is rectangular, and the length of the water storage tank can be set to be longer, so that the jet orifice can span a large height range of the blade body, and the response capability of the passive jet device is improved. The cavity 23 is rectangular parallelepiped, and the size of the cavity 23 is the same as the size of the sealing end 221. The width of the jet orifice is 0.005L, and the width of the cavity is 0.1L. The shell 21 is provided with a concave platform 25 at one side of the jet opening 222 of the water storage tank 22, a convex shoulder 112 matched with the concave platform 25 is arranged in the mounting groove 111, and the concave platform 25 and the convex shoulder 112 are fixed through a plurality of screws 3. When the shell 21 is installed, the shell 21 firstly slides into the installation groove 111 from one side of the blade body 1, the concave platform 25 and the convex shoulder 112 are limited, and then the sliding track of the shell 21 on the blade body 1 is filled, so that the shell 21 is embedded in the blade body 1, the shell 21 is prevented from being subjected to fluid pressure, and the structural strength and the smooth surface of the blade body 1 are ensured.

The utility model discloses at five blade centrifugal pumps's practical application, as shown in FIG. 3, passive form fluidic device 2 installs in the suction surface 11 afterbody 0.3 to 0.4L position department of the blade body 1 of centrifugal pump, and all installs passive form fluidic device 2 on every blade body 1.

Claims (8)

1. The utility model provides a can avoid centrifugal pump blade of fluid stall, characterized by, includes the blade body, and the blade body is equipped with the mounting groove in its suction surface one side, is equipped with passive form fluidic device in the mounting groove, and passive form fluidic device includes the casing, is equipped with aqua storage tank and the confined cavity with the external intercommunication of blade body in the casing, and aqua storage tank and cavity are separated through an elastic film.

2. The centrifugal pump blade capable of avoiding fluid stall of claim 1, wherein the chord length of the blade body bone line is L, and the mounting groove is located 0.3 ~ 0.4.4L forward of the tail end of the blade body.

3. A centrifugal pump blade capable of avoiding fluid stall according to claim 1, wherein the water storage tank is of a symmetrical structure and comprises four wall surfaces, one set of opposite wall surfaces in the water storage tank are parallel and opposite, the other set of opposite wall surfaces in the water storage tank gradually draw together from inside to outside so that the water storage tank forms a tapered spray pipe shape, the water storage tank comprises a flow sealing end and a jet orifice which are positioned at two ends of the water storage tank, the flow sealing end is parallel to the jet orifice, the jet orifice is positioned on a suction surface of the blade body, and the edge of the elastic film is attached to the flow sealing end.

4. A centrifugal pump vane capable of avoiding fluid stall as claimed in claim 3, wherein said jet opening is rectangular in shape, said flow-sealing end is rectangular in shape, the width of the jet opening is 0.0025 to 0.0075L, the width of the cavity is the same as the width of the flow-sealing end, and the width of the cavity is 0.1 to 0.15L.

5. A centrifugal pump blade capable of avoiding fluid stall according to claim 3 or 4, wherein the generatrix of the wall surface of the water storage tank is in an's' shape formed by overlapping two tangent arcs, the central angle of each arc is less than 90 degrees, and the tangent at the jet opening is parallel to the tangent at the flow-blocking end.

6. A centrifugal pump blade capable of avoiding fluid stall as claimed in claim 1 or claim 3, wherein said flexible membrane is formed of a silicone material.

7. A centrifugal pump blade capable of avoiding fluid stall as claimed in claim 1 wherein said casing is formed from a metal foil.

8. A centrifugal pump blade capable of avoiding fluid stall according to claim 1 or 7, wherein the casing is shaped like a cuboid, the casing is provided with a concave platform at one side of a jet opening of the water storage tank, a convex shoulder matched with the concave platform is arranged in the mounting groove, and the concave platform and the convex shoulder are fixed through a plurality of screws.

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