Bulb tubular pump resistance reducing and vortex eliminating device based on fish bionics

Abstract

The utility model discloses a bulb tubular pump resistance reducing and vortex eliminating device based on fish bionics, which belongs to the technical field of tubular pumps and comprises a jet flow resistance reducing structure and a vortex eliminating empennage structure. The jet flow resistance reduction structure comprises a plurality of jet flow holes formed in the side wall of the front section of the bulb body in the circumferential direction and a jet flow water supply pipeline communicated with the jet flow holes. The vortex elimination empennage structure is arranged at the tail end of the bulb body and comprises two side diffusion wings which are vertically symmetrical and a concave arc-shaped contraction wing connected with the two side diffusion wings, and the tail length of the diffusion wings reaches the extension line of the contraction section of the bulb body. According to the jet flow resistance reduction structure, the thickness of the viscous bottom layer of the side wall can be increased through fluid jetted by the jet flow holes, the flow velocity gradient at the side wall is reduced, and the frictional resistance of the bulb body is reduced; the vortex elimination empennage structure can balance tail end pressure distribution and weaken excessive flow field distribution change caused by the contraction section of the bulb body, so that the vortex influence is reduced.

Description

Technical Field

[0001] The utility model relates to a drag reducing and vortex eliminating device for a bulb tubular pump, in particular to a drag reducing and vortex eliminating device for a bulb tubular pump based on fish bionics. Background Art

[0002] With the advancement of the second phase of the East Route of the South-to-North Water Diversion Project, low-head and high-flow bulb-type tubular pumps have been widely adopted due to their excellent hydraulic performance and high operating efficiency. As one of the main structures of the bulb-type tubular pump, the shape design of the bulb body is crucial to the hydraulic performance of the pump. There are about 400,000 low-head pumps in my country, with a total installed capacity of more than 40 million kilowatts. If the efficiency of the pump unit is improved by one percentage point, 4 billion kilowatt-hours of electricity can be saved each year. On the other hand, since the bulb-type tubular pump occupies part of the flow channel, the flow channel area of ​​the bulb body contraction section is increased, the flow velocity is partially reduced, and there is still some fluid velocity circulation that has not been effectively eliminated, which is easy to form a local low-speed area at the tail of the bulb body, and form vortex vortex and other unfavorable flow areas. At present, most of the measures to reduce the hydraulic loss of the bulb body section are to optimize the bulb body shape, but the optimization of its geometric shape ultimately has an efficiency bottleneck that cannot be improved, so it is necessary to start from other aspects to improve the unit efficiency.

[0003] Studies have shown that the shark gill jet injects low-speed fluid into the wall downstream of the outlet, increases the thickness of the low-speed flow field near the wall, and reduces the flow velocity gradient near the wall, which can effectively reduce the friction resistance; by setting up the tail wing, the remaining part of the velocity circulation can be eliminated, the pressure distribution at the tail end can be balanced, and the purpose of weakening the vortex can be achieved. For example, in the prior art, patent CN103112547A discloses a microporous jet drag reduction structure on the surface of a ship. It includes: a guide groove (3) arranged below the waterline of the ship, a porous shell plate (5) is covered on the guide groove (3) on the side of the ship, and a bow mesh plate (6) is covered on the guide groove (3) at the front of the ship. The cross-sectional size of the guide groove (3) extending to the stern part gradually decreases to form a drain (2). The patent mentions that the boundary layer flow field is changed by forming a microporous jet on the wall below the waterline of the ship to achieve the purpose of reducing the navigation resistance of the ship. However, its vortex elimination effect still needs to be further improved. Utility Model Content

[0004] The utility model aims to solve the above-mentioned problems existing in the prior art and proposes a bulb tubular pump drag reduction and vortex elimination device based on fish bionics, which reduces the friction resistance of the bulb body by jet drag reduction and sets a tail fin-type vortex elimination tail wing at the tail end of the bulb body to reduce the influence of the vortex on the unit.

[0005] In order to achieve the above utility model purpose, the technical solution of the utility model is as follows:

[0006] A drag reduction and vortex elimination device for a bulb cross-flow pump based on fish bionics, characterized in that it includes a jet drag reduction structure and a vortex elimination tail wing structure; the jet drag reduction structure includes a plurality of jet holes arranged on the circumference of the side wall of the front section of the bulb body and a jet water supply pipeline connected thereto; the vortex elimination tail wing structure is arranged at the rear end of the bulb body, and includes two side diffusion wings that are symmetrical up and down and an inwardly concave arc-shaped contraction wing connecting the two side diffusion wings, and the tail length of the diffusion wing reaches the extension line of the contraction section of the bulb body.

[0007] Furthermore, the symmetry centers of the diffusion wings on both sides coincide with the central axis of the bulb body.

[0008] Furthermore, the jet water supply pipeline includes a water inlet arranged at the front end of the bulb body, a water pipe connecting the jet hole and the water inlet, and a motor pump connected to the water pipe.

[0009] Furthermore, the jet hole is located in a diffusion angle reduction area of ​​the diffusion section of the bulb body.

[0010] Furthermore, a plurality of jet holes are evenly distributed along the circumference of the side wall of the bulb body, and the number of the jet holes takes a maximum value while satisfying the structural strength and the placement of components inside the bulb body.

[0011] Furthermore, a filter screen is provided at the water inlet.

[0012] Furthermore, the distance between the longitudinal section where the jet hole is located and the front end surface of the bulb body is 0.4R, where R is the radius of the impeller of the bulb crossflow pump.

[0013] Furthermore, the diffusion angle of the diffusion wing is the same as the diffusion angle of the front end of the bulb body.

[0014] Furthermore, the vertical length W of the diffusion wing is 0.4R, the longitudinal thickness H is 0.1R, and R is the radius of the impeller of the bulb crossflow pump.

[0015] Furthermore, the distance L from the outer edge of the arc line of the concave bottom of the arc-shaped contraction wing to the starting end of the diffusion wing is 0.2R, and R is the radius of the impeller of the bulb crossflow pump.

[0016] In summary, the utility model has the following advantages:

[0017] 1. The jet drag reduction structure of the utility model can increase the thickness of the viscous bottom layer of the side wall, reduce the velocity gradient at the side wall, and reduce the friction resistance of the bulb body through the fluid ejected through the jet hole; the vortex elimination tail wing structure can balance the pressure distribution at the tail end, reduce the excessive change of the flow field distribution caused by the contraction section of the bulb body, and thus reduce the influence of vortex;

[0018] 2. The utility model makes full use of the water inlet set up at the rear of the pump guide vane to lead water into the interior of the bulb body for motor cooling, and then pumps the cooling water into the jet port at the side wall of the bulb body, thereby reducing the friction resistance of the bulb body and achieving water cooling of the motor, which plays a role in reducing costs and increasing efficiency;

[0019] 3. The jet hole of the utility model is located in the area where the diffusion angle of the bulb body is reduced, so the fluid is easier to transfer along the wall, and the jet fluid effectively adheres to the bulb body to form a low flow rate area on its surface, which has the best drag reduction effect;

[0020] 4. The extension line of the contraction section of the bulb body of the utility model just extends to the tail of the diffuser wing, so that the tail of the bulb body forms a more obvious tapered tail. At the same time, due to the spacing effect of the diffuser tail, the fluids on the left and right sides of the tail will not quickly aggregate and collide, thereby reducing the dissipation of turbulent kinetic energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0022] Figure 2 This is a schematic diagram of the water inlet distribution of the utility model;

[0023] Figure 3 This is a schematic diagram of the structure of the vortex-eliminating tail wing of the utility model;

[0024] Figure 4 This is a schematic diagram of the structural parameters of the vortex-eliminating tail wing of the utility model;

[0025] Figure 5 This is a before and after comparison diagram of the turbulent kinetic energy distribution of the central axis section of the bulb body of the utility model;

[0026] Figure 6 The effect of the number of jet holes on the shear stress distribution on the bulb wall;

[0027] Figure 7 is a schematic diagram of the structure of a bulb body;

[0028] In the figure:

[0029] 1. Bulb body, 2. flow channel, 3. guide vane section, 4. impeller section, 101. diffusion section, 102. cylinder section, 103. contraction end, 104. front end face, 5. jet hole, 6. water inlet, 7. water guide pipe, 8. motor pump, 9. vortex elimination tail wing structure, 901. diffusion wing, 902. arc-shaped contraction wing. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the utility model, the utility model is further described below in conjunction with preferred embodiments and drawings. Those skilled in the art should understand that the content described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the utility model.

[0031] The utility model discloses a drag reduction and vortex elimination device for a bulb tubular pump based on fish bionics, which is mainly used in bulb tubular pumps to achieve drag reduction and vortex elimination. Figure 1 The bulb pump shown in the figure comprises a flow channel 2, a bulb body 1, a guide vane section 3 and an impeller section 4. The typical olive-shaped bulb body 1 structure is as follows: Figure 7 As shown, with the flow direction as the front end, the bulb body 1 includes a diffusion section 101, a barrel section 102 and a contraction section from the front end surface 104 to the rear end. The angle α in the figure is the diffusion angle of the front end of the bulb body 1.

[0032] The drag reduction and vortex elimination device comprises a jet drag reduction structure and a vortex elimination tail wing structure 9 arranged on the bulb body 1, wherein the jet drag reduction structure comprises a plurality of jet holes 5 arranged on the circumference of the side wall of the front section of the bulb body 1 and a jet water supply pipeline connected to the jet holes 5. The vortex elimination tail wing structure 9 is connected to the tail end of the bulb body 1, and comprises two symmetrical diffusion wings 901 on both sides and an inwardly concave arc-shaped contraction wing 902 connecting the two diffusion wings 901, and the tail length of the diffusion wing 901 reaches the extension line of the contraction section of the bulb body 1.

[0033] In this embodiment, the jet water supply pipeline includes a water inlet 6 arranged at the front end of the bulb body 1, a water pipe 7 connecting the jet hole 5 and the water inlet 6, and a motor pump 8 connected to the water pipe 7. Preferably, the water inlet 6 is arranged on the front end surface 104 of the bulb body 1, and the water pipe 7 is wound around the outer wall of the pump drive motor in the bulb body 1. The jet water supply pipeline uses the water introduced into the bulb body 1 to take away the heat of the pump to achieve the cooling of the bulb cross-flow pump. Preferably, the water pipe 7 is made of a material with strong thermal conductivity, and a heat-conducting copper pipe with an anti-rust coating can be used.

[0034] Furthermore, a filter screen is provided at the water inlet 6 to filter impurities in the water to prevent the ejection holes 5 from being blocked.

[0035] In the utility model, the fluid ejected by the jet drag reduction structure through the jet hole 5 can increase the thickness of the viscous bottom layer of the side wall, reduce the flow velocity gradient at the side wall, and reduce the friction resistance of the bulb body 1; the vortex-eliminating tail wing structure 9 can balance the pressure distribution at the tail end, weaken the excessive change in the flow field distribution caused by the contraction section of the bulb body 1, and thus reduce the influence of the vortex.

[0036] Embodiment 1

[0037] This embodiment provides a drag reduction and vortex elimination device for a bulb tubular pump based on fish bionics, which includes a jet drag reduction structure and a vortex elimination tail wing structure 9 arranged on the bulb body 1, wherein the jet drag reduction structure includes a plurality of jet holes 5 arranged on the circumference of the side wall of the front section of the bulb body 1 and a jet water supply pipeline connected to the jet holes 5. The vortex elimination tail wing structure 9 is connected to the tail end of the bulb body 1, and includes two side diffusion wings 901 symmetrically arranged up and down and an inwardly concave arc-shaped contraction wing 902 connecting the two side diffusion wings 901, and the tail length of the diffusion wing 901 reaches the extension line of the contraction section of the bulb body 1.

[0038] The jet water supply pipeline includes a water inlet 6 arranged at the front end of the bulb body 1, a water pipe 7 connecting the jet hole 5 and the water inlet 6, and a motor pump 8 connected to the water pipe 7. In this embodiment, a plurality of water inlets 6 are provided and evenly distributed on the front end surface 104 of the bulb body 1, a plurality of water pipes 7 are provided corresponding to the number of water inlets 6, and the jet holes 5 are evenly distributed in the circumferential direction of the outer circle where the longitudinal section of the bulb body 1 is located. Figure 2 As shown, taking four water inlets 6 as an example, four water pipes 7 are provided corresponding to the four water inlets 6, and the four water pipes 7 are all wound around the outer wall of the pump drive motor in the bulb body 1. The preferred size of the water inlet 6 is 10-20 mm.

[0039] In this embodiment, the jet hole 5 is located in the area where the diffusion angle of the diffuser section 101 of the bulb body 1 decreases, the fluid is more likely to be transported along the wall, and the jet fluid effectively adheres to the bulb body 1 to form a low velocity area on its surface, which has the best drag reduction effect. Preferably, the distance S between the longitudinal section where the jet hole 5 is located and the front end surface 104 of the bulb body 1 is preferably 0.4R, where R is the radius of the impeller of the bulb crossflow pump.

[0040] Preferably, the jet holes 5 are evenly distributed along the circumference of the side wall of the bulb body 1, and the number of the jet holes 5 is as large as possible while satisfying the structural strength and the placement of the components inside the bulb body 1. Figure 6 The influence of the number of jet holes on the shear stress distribution on the bulb wall is shown in the figure. In the simulation, when the number of jet ports increases to 128, the drag reduction rate reaches 23.069%. As the number of jet ports increases, the low velocity zones formed around each port interact to form an obvious annular low velocity zone, and the wall shear stress in this area is significantly reduced. Under this simulation condition, the optimal jet velocity is 3.17V, where V is the average velocity on the two surfaces of the flow channel at the rear end of the guide vane.

[0041] Embodiment 2

[0042] On the basis of the first embodiment, this embodiment further describes the vortex elimination tail wing structure 9:

[0043] like Figure 3As shown, the vortex elimination tail structure 9 is connected to the tail end of the bulb body 1, including two symmetrical diffusion wings 901 on both sides and an inwardly concave arc-shaped contraction wing 902 connecting the two diffusion wings 901. The tail of the diffusion wing 901 is extended to the extension line of the contraction section of the bulb body 1. The extension line of the contraction section of the bulb body 1 just extends to the tail of the diffusion wing 901, so that the tail of the bulb body 1 forms a more obvious tapered tail. At the same time, due to the spacing effect of the diffusion tail, the fluids on the left and right sides of the tail will not quickly aggregate and collide, thereby reducing the dissipation of turbulent kinetic energy.

[0044] Further, such as Figure 4 As shown, the vertical length W of the diffusion wing 901 is preferably 0.4R, and the vertical thickness of the diffusion wing 901 along the central axis of the bulb body 1 is preferably 0.1R; the distance L from the outer edge of the arc line of the concave bottom of the arc-shaped contraction wing 902 to the starting end of the diffusion wing 901 is preferably 0.2R, where R is the radius of the impeller of the bulb crossflow pump. Preferably, the diffusion angle β of the diffusion wing 901 is the same as the diffusion angle α of the front end of the bulb body 1. Figure 5 The figure shows the before and after comparison of the turbulent kinetic energy distribution of the axial section of the bulb body 1. Under the setting parameters of the vortex elimination tail mechanism, the turbulent kinetic energy is reduced by 40%, making the flow state in the tail part of the bulb body 1 and the outlet wall surface prone to turbulent dissipation stable.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A fish bionic bulb tubular pump drag reduction and vortex elimination device, characterized in that: The invention comprises a jet drag reduction structure and a vortex elimination tail wing structure (9); the jet drag reduction structure comprises a plurality of jet holes (5) arranged on the circumference of the side wall of the front section of the bulb body (1) and a jet water supply pipeline connected thereto; the vortex elimination tail wing structure (9) is arranged at the rear end of the bulb body (1), and comprises two upper and lower symmetrical diffusion wings (901) and an inwardly concave arc-shaped contraction wing (902) connecting the two diffusion wings (901), and the tail of the diffusion wing (901) is extended to the extension line of the contraction section of the bulb body (1).

2. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: The symmetry centers of the diffusion wings (901) on both sides coincide with the central axis of the bulb body (1).

3. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: The jet water supply pipeline comprises a water inlet (6) arranged at the front end of the bulb body (1), a water guide pipe (7) connecting the jet hole (5) and the water inlet (6), and a motor pump (8) connected to the water guide pipe (7).

4. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: The jet hole (5) is located in a diffusion angle reduction region of the diffusion section (101) of the bulb body (1).

5. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: A plurality of jet holes (5) are evenly distributed along the circumference of the side wall of the bulb body (1), and the number of the jet holes (5) is maximized while satisfying the structural strength and the placement of components inside the bulb body (1).

6. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 3, characterized in that: A filter screen is provided at the water inlet (6).

7. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 4, characterized in that: The distance between the longitudinal section where the jet hole (5) is located and the front end surface (104) of the bulb body (1) is 0.4R, where R is the radius of the impeller of the bulb crossflow pump.

8. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: The diffusion angle of the diffusion wing (901) is the same as the diffusion angle of the front end of the bulb body (1).

9. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: The vertical length W of the diffusion wing (901) is 0.4R, and the longitudinal thickness H is 0.1R, where R is the radius of the impeller of the bulb crossflow pump.

10. The fish bionic bulb tubular pump drag reduction and vortex elimination device according to claim 1, characterized in that: The distance L between the outer edge of the arc line of the concave bottom of the arc-shaped contraction wing (902) and the starting end of the diffusion wing (901) is 0.2R, where R is the radius of the impeller of the bulb crossflow pump.

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