Novel structure for reducing pressure pulsation and noise of mixed-flow pump

Abstract

The invention particularly relates to a novel structure for reducing pressure pulsation and noise of a mixed-flow pump, which is applied to the mixed-flow pump, the mixed-flow pump comprises a pump cavity, the pump cavity is provided with a first inlet, an impeller is arranged in the pump cavity, an impeller runner is formed in the impeller, and an inlet of the impeller runner faces the first inlet and surrounds the circumferential direction of the first inlet. A protruding block structure is arranged on the inner wall face of the first inlet, the cross section of the side, away from the inner wall face of the first inlet, of the protruding block structure is in a parabola shape, so that the thickness of the two sides of the protruding block structure is smaller than that of the middle of the protruding block structure in the axial direction of the first inlet, and one side of the protruding block structure is inserted into an inlet of the impeller channel. The bump structure is arranged at the first inlet, so that the flow velocity of a medium at the pump inlet is increased, the increased inlet flow velocity can improve the kinetic energy of fluid, the attachment of the fluid on the surfaces of pump blades is facilitated, the flow separation is reduced, the backflow vortex at the pump inlet is inhibited, and the pressure pulsation value of the pump is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pump structures, and in particular relates to a novel mixed flow pump structure for reducing pressure pulsation and noise. Background Art

[0002] Mixed flow pump is a commonly used liquid conveying equipment. The working principle of mixed flow pump is that when the impeller inside the pump body rotates at high speed, the liquid in the pump body is affected by centrifugal force and is thrown to the outer edge of the impeller, forming a high-speed rotating vortex. As the liquid is thrown out, a low-pressure area is formed in the center area of ​​the impeller. The low-pressure area allows new liquid to be sucked into the pump to fill the position of the thrown out liquid.

[0003] Pressure pulsation refers to the phenomenon of periodic pressure changes in a fluid in a pipeline or system. When a mixed flow pump is working, pressure pulsation will occur. Pressure pulsation will have many adverse effects on the pump, such as vibration and noise, mechanical wear and reduced pump efficiency, which will eventually shorten the service life of the pump and reduce the liquid transport capacity.

[0004] At present, most of the methods to reduce pressure pulsation start from changing the pump blade parameters, such as changing the impeller shape, number of impellers, blade angle, etc., to reduce the generation of pressure pulsation. Or install dampers or buffers at the inlet and outlet of the pump to reduce the impact of pressure pulsation. However, the above two methods require significant improvements to the pump on the one hand, and the implementation process is complicated, and on the other hand, the cost of improvement is high. Summary of the invention

[0005] The object of the present invention is to provide a new structure for reducing pressure pulsation and noise of a mixed flow pump, by which the pressure pulsation of the mixed flow pump can be reduced and the structure has the advantages of simple structure and high efficiency.

[0006] To achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: the embodiment of the present application provides a new type of mixed flow pump structure for reducing pressure pulsation and noise, which is applied to a mixed flow pump, wherein the mixed flow pump includes a pump chamber, the pump chamber is provided with a first inlet, the pump chamber is provided with an impeller, the impeller forms an impeller flow channel, the inlet of the impeller flow channel faces the first inlet, and the inner wall surface of the first inlet is provided with a protrusion structure around the circumference of the first inlet, and the cross-section of the protrusion structure on the side away from the inner wall surface of the first inlet is parabolic, so that along the axial direction of the first inlet, the thickness of both sides of the protrusion structure is less than the thickness of the middle part of the protrusion structure, and one side of the protrusion structure is inserted into the inlet of the impeller flow channel.

[0007] In some embodiments, the pump chamber is provided with an inlet channel, the inlet channel is communicated with the first inlet, and one side of the protrusion structure is provided at the inlet channel.

[0008] In some embodiments, a distance K between the bump structure and the diameter-changing section of the inlet channel is 10-13 mm.

[0009] In some embodiments, along the axial direction of the first inlet, the protrusion structure extends by a length L, and the protrusion structure protrudes from the inner wall of the first inlet by a height M, satisfying 3≤L / M≤3.5.

[0010] In some embodiments, the radius of the first inlet is R, and the height of the protrusion structure protruding from the inner wall of the first inlet is M, satisfying 0.14≤M / R≤0.145.

[0011] In some embodiments, the bump structure is welded to the pump chamber.

[0012] In some embodiments, the projection structure is connected to the pump chamber by bolts.

[0013] The present invention has the following beneficial effects: 1. By arranging a convex block structure at the first inlet, the flow velocity of the medium at the pump inlet is increased. The increased inlet flow velocity can increase the kinetic energy of the fluid, help the fluid to adhere to the surface of the pump blades, reduce flow separation, and thus inhibit the backflow vortex at the pump inlet. At the same time, the convex block can also prevent the backflow vortex from extending and developing toward the impeller direction, thereby reducing the backflow vortex at the pump inlet and improving the pressure pulsation value of the pump.

[0014] 2. It has the advantages of low cost and easy transformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A structural view of a novel mixed flow pump of the present invention for reducing pressure pulsation and noise;

[0016] Figure 2 for Figure 1 A magnified image of point A;

[0017] Figure 3 It is a structural schematic diagram of the impeller flow channel of the present invention before and after the protrusion structure is provided;

[0018] Figure 4 The diagram of pressure pulsation change before and after optimization of the intermediate streamline portion of the guide vane inlet of the mixed flow pump of the present invention;

[0019] Figure 5 The noise frequency domain diagram of the mixed flow pump before and after the optimization of the intermediate streamline part of the blade inlet;

[0020] Figure 6 The noise frequency domain diagram of the outlet center point of the mixed flow pump of the present invention before and after optimization;

[0021] Figure 7The noise frequency domain diagram of the inlet center point of the mixed flow pump of the present invention before and after optimization;

[0022] Figure 8 Optimizing the front and rear noise frequency domains of the intermediate streamline portion of the guide vane inlet of the mixed flow pump of the present invention;

[0023] Fig. 9 A comparison diagram of the lift before and after the mixed flow pump of the present invention is provided with a convex block structure;

[0024] Fig.10 A comparison diagram of the hydraulic efficiency of the mixed flow pump of the present invention before and after the protrusion structure is provided;

[0025] Fig.11 This is a structural schematic diagram of a convex block structure provided with a concave groove in the present invention.

[0026] Figure numbers: 1-impeller flow channel, 2-impeller, 3-pump cover, 4-inlet channel, 5-bump structure, 6-recessed groove, 7-bolt. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0028] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0029] like Figure 1 As shown, an embodiment of the present application provides a new type of mixed flow pump structure for reducing pressure pulsation and noise, which is applied to a mixed flow pump. The mixed flow pump includes a pump chamber, the pump chamber is provided with a first inlet, an impeller 2 is provided in the pump chamber, the impeller 2 forms an impeller flow channel 1, the inlet of the impeller flow channel 1 faces the first inlet, and a protrusion structure 5 is provided on the inner wall surface of the first inlet in the circumference around the first inlet. The cross-section of the protrusion structure 5 on one side of the inner wall surface away from the first inlet is parabolic, so that along the axial direction of the first inlet, the thickness of both sides of the protrusion structure 5 is less than the thickness of the middle part of the protrusion structure 5, and one side of the protrusion structure 5 is inserted into the inlet of the impeller flow channel 1.

[0030] The pump chamber is a chamber used by the mixed flow pump to transmit the medium. In general, the working principle of the mixed flow pump can be: when the impeller 2 rotates, a low-pressure area is formed in the center of the impeller 2, so that the medium can be sucked into the impeller flow channel 1. At the same time, part of the medium is thrown to the edge of the impeller 2 along the impeller flow channel 1, so that the pressure and flow rate of the medium can be increased, so that the medium can flow to the outlet channel of the mixed flow pump and be discharged from the outlet channel.

[0031] There is a certain gap between the portion of the convex structure 5 disposed at the inlet of the impeller channel 1 and the inner wall of the inlet of the impeller channel 1, so that the convex structure 5 does not hinder the rotation of the impeller 2. The gap can be set as small as possible.

[0032] A avoidance portion may be provided on the side of the bump structure 5 close to the inner wall of the first inlet to avoid the structure in the pump chamber. For example, the avoidance portion may be used to enable the impeller 2 to be partially disposed on the side of the bump structure 5 close to the inner wall of the first inlet, so that the bump structure 5 can be inserted into the impeller flow channel 1.

[0033] The side of the bump structure 5 away from the inner wall of the inlet includes a first side wall facing outside the pump chamber and a second side wall facing inside the pump chamber. The side of the second side wall away from the first side wall is arranged in the inlet of the impeller flow channel 1. The first side wall and the second side wall are connected by a rounded transition, so that the surface of the bump structure 5 close to the pump chamber can be parabolic.

[0034] The parabolic surface formed by the first side wall and the second side wall prevents sharp fluid flow domains from appearing when the medium flows through the bump structure 5, allowing the medium to enter smoothly, thereby improving the flow stability of the medium and enabling the bump structure 5 to produce the effect of reducing pressure pulsation and noise.

[0035] The bump structure 5 can also increase the flow rate of the medium entering the pump chamber, thereby suppressing the generation of the first inlet backflow vortex and reducing the pressure pulsation amplitude of the impeller 2.

[0036] In the embodiment of the present application, a bump structure 5 is provided at the first inlet so that the flow velocity of the medium at the pump inlet is increased. The increased inlet flow velocity can increase the kinetic energy of the fluid, help the fluid to adhere to the surface of the pump blades, reduce flow separation, and thus suppress the backflow vortex at the pump inlet. At the same time, the bump can also prevent the backflow vortex from extending and developing in the direction of the impeller 2, thereby reducing the backflow vortex at the pump inlet and improving the pressure pulsation value of the pump.

[0037] like Figure 4 As shown, through simulation calculation, the obtained data is processed to obtain the pressure pulsation change diagram before and after optimization of the middle streamline part of the guide vane inlet, where M1 is before optimization and M2 is after optimization. It can be clearly seen that the maximum amplitude of the pressure pulsation has been optimized to a great extent, indicating that this structure can improve the pressure pulsation of the pump.

[0038] like Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, after simulation calculation, the obtained data is processed to obtain a frequency domain comparison diagram of the noise sound pressure level of each part of the pump before and after modification. The amplitude change of the noise at the inlet, blades, and guide vanes of the mixed flow pump at each frequency is larger than before the improvement, which shows that the bump structure 5 of the embodiment of the present application also has the function of reducing working noise.

[0039] like Fig. 9 and Fig.10 As shown, after specific experiments, the lift and hydraulic efficiency comparison curves before and after the modification are obtained. It can be seen that both the lift and efficiency have increased after the convex structure 5 is set. Under the best working conditions, the efficiency is increased by 6.95% and the lift is increased by 9.97%, which means that this structure is feasible in practical application. It also proves that the convex structure 5 of the embodiment of the present application can also play a role in increasing the working efficiency of the pump and increasing the lift.

[0040] In some embodiments, the pump chamber is provided with an inlet channel 4 , the inlet channel 4 is communicated with the first inlet, and one side of the protrusion structure 5 is provided on the inlet channel 4 .

[0041] The inlet channel 4 is used to suck in the medium so that the medium can enter the impeller flow channel 1 .

[0042] The convex structure 5 is partially disposed in the inlet channel 4. On the one hand, the first side wall of the convex structure 5 can be smoothly matched with the inlet channel 4, thereby improving the stability of the medium when it flows from the inlet channel 4 into the impeller channel 1. On the other hand, the sealing effect between the inlet channel 4 and the impeller channel 1 can be increased.

[0043] In some embodiments, the distance K between the bump structure 5 and the diameter-changing section of the inlet channel 4 is 10-13 mm.

[0044] The diameter-changing section of the inlet passage 4 is well known to those skilled in the art, and its structure will not be described in detail here.

[0045] The advantage of such a configuration is that, on the one hand, it can reduce the stress concentration between the protrusion structure 5 and the inlet channel 4, thereby increasing the service life of the inlet channel 4, and on the other hand, it can reduce the risk of the protrusion structure 5 affecting the movement of the medium in the inlet channel 4.

[0046] In some embodiments, along the axial direction of the first inlet, the protrusion structure 5 extends by a length L, and the protrusion structure 5 protrudes from the inner wall of the first inlet by a height M, satisfying 3≤L / M≤3.5.

[0047] For example, L / M can be 3, 3.1, 3.2, 3.3, 3.4, or 3.5.

[0048] If L / M < 3, the adjustment effect of the protrusion structure 5 on the medium is not obvious, and the pressure pulsation amplitude cannot be reduced. If L / M > 3.5, the medium flow rate increases too fast, reducing the medium flow stability, which also reduces the effect of the protrusion structure 5.

[0049] When 3≤L / M≤3.5, the effect of the bump structure 5 on reducing the pressure pulsation amplitude can be increased.

[0050] In some embodiments, the radius of the first inlet is R, and the height of the bump structure 5 protruding from the inner wall of the first inlet is M, satisfying 0.14≤M / R≤0.145.

[0051] On the one hand, such a configuration can increase the medium flow stability, thereby reducing the pressure pulsation of the impeller 2. On the other hand, it makes the direction and speed of the medium entering the impeller 2 more suitable, thereby reducing the pressure pulsation caused by the medium impacting the impeller 2.

[0052] In some embodiments, the bump structure 5 is welded to the pump cavity.

[0053] The bump structure 5 is welded to the pump cavity, which ensures the connection reliability between the bump structure 5 and the pump cavity.

[0054] In some embodiments, the projection structure 5 is connected to the pump chamber via bolts 7 .

[0055] The bump structure 5 is connected to the pump chamber by bolts 7, so that the pump chamber can be detachably connected to the pump chamber, which is convenient for replacing the bump structure 5 and reduces the risk of damaging the pump chamber structure due to high temperature compared to welding.

[0056] In the embodiment of the present application, the bump structure 5 may include a first surface facing the inner wall of the first inlet, and a recessed groove 6 may be provided on the first surface circumferentially around the bump structure 5. Along the axial direction of the first inlet, the cross-section of the recessed groove 6 may be a triangular structure, and the large end of the triangular structure is close to the inner wall surface of the first inlet, and the tip is arranged on the side of the large end away from the inner wall surface of the first inlet.

[0057] like Fig.11As shown, the concave groove 6 separates the first surface into two parts. On the one hand, in the initial state, the concave groove 6 can make the protrusion structure 5 slightly bent, and the inner curved side of the protrusion structure 5 faces the inner wall of the first inlet. When the protrusion structure 5 is pressed against the inner wall of the first inlet by the bolt 7, along the axial direction of the first inlet, the two sides of the protrusion structure 5 can be as close to the inner wall of the inlet of the impeller flow channel 1 and the inner wall surface of the inlet channel 4 as possible, reducing the risk of sharp fluid flow domains, and can make the first side wall tightly against the inner wall surface of the inlet channel 4, increasing the sealing between the protrusion structure 5 and the inlet channel 4. On the other hand, when the protrusion structure 5 is against the inner wall of the first inlet, the protrusion structure 5 produces elastic deformation, so that the protrusion structure 5 can eliminate the matching clearance between the bolt 7 and the protrusion structure 5, that is, the concave groove 6 can also play an anti-loosening effect. On the other hand, the screw hole of the protrusion structure 5 for cooperating with the bolt 7 can be set on the inner wall surface of the recessed groove 6, which is convenient for setting the bolt 7 at an angle, so that the bolt 7 can be set on the pump cover 3, that is, the protrusion structure 5 and the pump cover 3 are connected by the bolt 7, so that the protrusion structure 5 can be fixed to the inner wall of the first inlet without changing the structure of the pump body.

[0058] The above embodiments are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, modifications, and substitutions made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A novel mixed flow pump structure for reducing pressure pulsation and noise, applied to a mixed flow pump, the mixed flow pump comprising a pump chamber, the pump chamber being provided with a first inlet, an impeller (2) being provided in the pump chamber, the impeller (2) being formed with an impeller flow channel (1), the inlet of the impeller flow channel (1) being directed toward the first inlet, and characterized in that: A protrusion structure (5) is provided on the inner wall surface of the first inlet in a circumferential direction around the first inlet, and the cross-section of the protrusion structure (5) on the side away from the inner wall surface of the first inlet is parabolic, so that along the axial direction of the first inlet, the thickness of the two sides of the protrusion structure (5) is smaller than the thickness of the middle part of the protrusion structure (5), and one side of the protrusion structure (5) is inserted into the inlet of the impeller flow channel (1).

2. The novel mixed flow pump structure for reducing pressure pulsation and noise according to claim 1 is characterized in that: The pump chamber is provided with an inlet channel (4), the inlet channel (4) is communicated with the first inlet, and one side of the convex block structure (5) is arranged on the inlet channel (4).

3. The novel mixed flow pump structure for reducing pressure pulsation and noise according to claim 2 is characterized in that: The distance K between the convex block structure (5) and the diameter-changing section of the inlet channel (4) is 10 to 13 mm.

4. The novel mixed flow pump structure for reducing pressure pulsation and noise according to claim 1 is characterized in that: Along the axial direction of the first inlet, the extension length of the protrusion structure (5) is L, and the height of the protrusion structure (5) protruding from the inner wall of the first inlet is M, satisfying 3≤L / M≤3.

5.

5. The novel mixed flow pump structure for reducing pressure pulsation and noise according to claim 1 is characterized in that: The radius of the first inlet is R, and the height of the protruding block structure (5) protruding from the inner wall of the first inlet is M, satisfying 0.14≤M / R≤0.

145.

6. The novel mixed flow pump structure for reducing pressure pulsation and noise according to claim 1 is characterized in that: The convex block structure (5) is welded to the pump chamber (1).

7. The novel mixed flow pump structure for reducing pressure pulsation and noise according to claim 1 is characterized in that: The convex block structure (5) is connected to the pump chamber (1) via bolts (7).

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