A hydrogen circulation pump rotor and a hydrogen circulation pump for improving axial clearance leakage

Abstract

The present invention discloses a hydrogen circulation pump rotor and a hydrogen circulation pump for improving axial clearance leakage, which includes a group of flow damping units arranged on both end faces of the cam rotor. The group of flow damping units is composed of two flow damping units symmetrically distributed about the long axis of the cam rotor. With the center of the cam rotor as the center of the circle, the flow damping units are arranged along the tangent line of a certain point on the arc of the circle. The flow damping unit includes an eddy current generator, a return flow groove, and a guide fin. By arranging regularly distributed flow damping units on the end face of the cam rotor, the flow damping unit on the high-pressure side generates eddy currents to block the gap between the end face of the high-pressure side cam rotor and the cover plate, thereby effectively reducing the generation of axial clearance leakage flow of the hydrogen circulation pump. The flow damping unit on the low-pressure side forms a return flow impact to reduce axial clearance leakage, thereby improving the volumetric efficiency and working performance of the hydrogen circulation pump.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid machinery, and particularly to a hydrogen circulation pump rotor and a hydrogen circulation pump for improving axial clearance leakage. Background Art

[0002] At present, the cam rotor pump is used as a gas circulation pump and has the advantages of high vacuum degree, corrosion resistance, high reliability, simple structure and wide adjustment range when transporting gases. Therefore, it is widely used in fields such as aerospace, new energy vehicles, and ships.

[0003] When designing a cam-type hydrogen circulation pump, in order to avoid friction and ensure the safe operation of the hydrogen circulation pump, a certain clearance should be left between the two end faces of the rotors and the pump cover. Although the proportion of the clearance size to the entire rotor chamber is very small, the clearance is prone to generate backflow under the pressure difference of adjacent chambers, which greatly affects the flow state inside the pump. An overly large clearance size causes a large amount of gas leakage at the clearance during the working process, resulting in volumetric loss. The large-scale leakage flow also interferes with the flow state of the chamber and affects the working efficiency of the pump; an overly small clearance size not only has high requirements for the manufacturing process, but also has the problem of ice slag blocking rotation during low-temperature startup in applications.

[0004] After retrieval, among the existing publicly disclosed cam-type hydrogen circulation pumps, the structure described in a patent application such as a two-stage rotor structure and a hydrogen circulation pump applicable to a hydrogen circulation pump (CN202210169244.7) can only prevent the working medium from leaking to the outside of the pump through the shaft clearance, and cannot reduce the leakage of the medium between adjacent chambers through the axial clearance. The lobed rotor of a roots-type hydrogen circulation pump designed in a patent (CN202020946094.2) has good meshing performance and a small clearance, but can only reduce the leakage of the medium through the clearance between the rotors and cannot reduce the axial clearance leakage.

[0005] After research, the influence of the axial clearance between the rotor end face and the pump cover on the pump performance is greater than the influence of the clearances between the rotors and between the rotor tip and the inner wall of the chamber. Therefore, it is necessary to design a structure and method for effectively reducing the axial clearance leakage of a cam-type hydrogen circulation pump. Summary of the Invention

[0006] In order to solve the deficiencies existing in the prior art, the present application proposes a hydrogen circulation pump rotor and a hydrogen circulation pump for improving axial clearance leakage. By arranging regularly distributed flow damping units on the cam rotor end face, the flow damping units on the high-pressure side block the clearance between the high-pressure side cam rotor end face and the cover plate by generating eddy currents, thereby effectively weakening the generation of the axial clearance leakage flow of the hydrogen circulation pump; the flow damping units on the low-pressure side form a backflow impact to reduce the axial clearance leakage, thereby improving the volumetric efficiency and working performance of the hydrogen circulation pump.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A hydrogen circulation pump rotor for improving axial clearance leakage, comprising:

[0009] A flow damping unit group arranged on both end faces of the cam rotor, the flow damping unit group is composed of 2 flow damping units symmetrically distributed about the long axis of the cam rotor; with the center of the cam rotor as the center of the circle, the flow damping units are arranged along the tangent line at a certain point on the arc of the circle.

[0010] The flow damping unit includes

[0011] An eddy current generator, the eddy current generator is a triangular prism, one side edge is arranged towards the leakage incoming flow direction, and the three side edges and three side faces of the eddy current generator all extend backward to form a swept-back triangular prism;

[0012] A return flow groove, the return flow groove is a "wing-shaped" groove, the return flow groove is arranged behind the eddy current generator, and gradually becomes shallower from deep to the back from the eddy current generator;

[0013] A guide fin, the guide fin is of a "wing-shaped" structure, and the guide fin is fixedly arranged in the return flow groove, and a return flow groove flow channel is formed between the guide fin and the return flow groove; the upper surface of the guide fin is higher than the upper opening of the return flow groove.

[0014] Furthermore, multiple concentric arcs are set with the center of the cam rotor as the center of the circle, and the adjacent arcs are arranged at equal intervals, and the interval is denoted as ΔR, ΔR>2w, where w is the width of the eddy current generator.

[0015] Furthermore, at least one flow damping unit group is arranged on the arc with the center of the cam rotor as the center of the circle.

[0016] Furthermore, with the long axis of the cam rotor as the boundary, the structural units on the same side of the cam rotor face the same direction, and the structural units on both sides are symmetrically distributed about the long axis of the cam rotor.

[0017] Furthermore, the included angle between the first side edge and the vertical direction is the swept-back angle θ, and 0°<θ<90°.

[0018] Furthermore, both of the two incoming flow side faces of the eddy current generator are straight faces or concave arc faces, and the back flow side face connected to the return flow groove is a concave arc face.

[0019] Furthermore, among the three side faces of the eddy current generator, the side face opposite to the first side edge is the back flow side face, the smooth front end of the return flow groove is aligned with the back flow side face of the eddy current generator, and the groove surface of the smooth front end of the return flow groove is smoothly connected with the concave arc face of the back flow side face of the eddy current generator to form a smoothly transitional arc surface.

[0020] Further, the widths of the return flow groove, the flow guiding fins and the eddy current generator are equal, and 1 mm < w < 5 mm is taken.

[0021] Further, the distance from the upper surface of the flow guiding fin to the end face of the cam rotor is denoted as h2, and 0.1 mm < h2 < h1 is taken, where h1 is the height of the eddy current generator, and 0.2 mm < h1 < 1 mm is taken.

[0022] A hydrogen circulation pump for improving axial clearance leakage, comprising:

[0023] A pump body;

[0024] Two cam rotors arranged in the pump body, and a rotating shaft hole is provided at the center of each cam rotor;

[0025] At least one flow damping unit group arranged on the end face of each cam rotor;

[0026] Pump covers and gearbox covers arranged at the upper and lower ends of the pump body;

[0027] Gears, each cam rotor is equipped with a gear, and the gear is fixedly connected to the cam rotor through a rotating shaft.

[0028] Advantages of the present invention:

[0029] 1. In the present application, the eddy current generator is of a swept-back triangular prism structure. The height h1 of the swept-back triangular prism structure is less than the axial clearance of the rotor end face. The eddy current generator of the swept-back triangular prism structure will disturb the leakage incoming flow, induce flow transition around the body, form an eddy current at the rear, and block the leakage gap.

[0030] 2. In the present application, a "wing type" groove with the same width is opened in parallel behind the eddy current generator. The flow guiding fin is located in the groove and fixedly connected to the rotor. The flow guiding fin and the groove are both of "wing type" structures, and the suction surface of the "wing type" flow guiding fin is higher than the rotor end face by a certain distance, so that the pressure surface guides the incoming flow into the return flow groove.

[0031] 3. In the present application, the eddy current generator, the groove and the flow guiding fin together form a hook-shaped return flow groove structure. The air flow is guided by the pressure surface of the "wing type" flow guiding fin into the return flow groove, and shoots at the leakage flow at a high speed of 0-90° with the incoming flow along the back of the eddy current generator of the swept-back triangular prism structure, forming a reverse swirl to prevent the leakage flow from continuing to flow.

[0032] 4. The vortex generators and the return channels are symmetrically distributed on the high-pressure side and the low-pressure side of the rotor. When the leakage flow occurs, both structures function simultaneously and can function in both the forward and reverse rotation cases. The vortex generators with the backward-swept triangular prism structure on the high-pressure side accelerate the transition of the leakage flow to turbulence, generating a vortex structure that blocks the flow channel and prevents the leakage flow from flowing; the return channel structure on the low-pressure side guides the leakage flow to flow reversely, forming a swirling flow when impacting with the forward leakage flow, preventing the leakage flow from flowing forward. Moreover, the existence of the vortex generators and the return channels allows the clearance distance to be enlarged to a certain extent, avoiding the problem of ice slag jamming during low-temperature startup. Description of the Drawings

[0033] Figure 1 are the top view and the front view of the vortex generator and the return channel structures;

[0034] Figure 2 is the schematic cross-sectional structure diagram of the vortex generator and the return channel on the rotor;

[0035] Figure 3 is the schematic position diagram of the vortex generator and the return channel;

[0036] Figure 4 is the schematic overall structure diagram of the hydrogen circulation pump;

[0037] Among them, 1. Cam rotor, 2. Vortex generator, 3. Return channel, 4. Guide fin, 5. Shaft hole, 6. Pump cover, 7. Pump body, 8. Gear, 9. Gearbox cover. Detailed Implementation Manner

[0038] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] Embodiment 1

[0040] During the working process, a pressure difference will be generated on both sides of the two cam rotors 1; under the action of the pressure difference, the working medium will flow from the high-pressure side to the low-pressure side; therefore, the working medium will leak at the clearance between the end face of the cam rotor 1 and the pump cover 6 and the gearbox cover 9.

[0041] Combined with the attached Figures 1-4 , a hydrogen circulation pump rotor for improving axial clearance leakage designed by the present invention is provided with a plurality of regularly distributed flow damping units on both end faces of the cam rotor 1 respectively. A single flow damping unit is composed of a vortex generator 2, a return channel 3 and a guide fin 4. Among them, taking 2 symmetrically distributed flow damping units on the end face as a group, a flow damping unit group is formed, and this flow damping unit group can simultaneously realize the functions of inducing vortices to block the axial clearance and the return impact to hinder the leakage flow.

[0042] The following combines Figure 1 and 2 to introduce the structures of the eddy current generator 2, the return flow groove 3, and the guide fins 4 in each flow damping unit respectively:

[0043] 1. Eddy current generator 2

[0044] The eddy current generator 2 has a triangular prism structure, and the bottom surface of the triangular prism is fixed on the end face of the cam rotor 1. One side edge of the triangular prism faces the direction of the leakage incoming flow, and this side edge is called the first side edge; when the eddy current generator 2 is on the high-pressure side, the two side faces sharing the same side edge with the first side edge serve as the incoming flow faces of the flow damping unit, and the side face opposite to the first side edge is the backflow side face. The three side edges and the three side faces of the triangular prism all extend backward to form a swept design. The swept design of the eddy current generator 2 can ensure that the high-speed jet flowing along the back of the eddy current generator 2 in the return flow groove 3 forms an angle with the incoming flow within the range of 0 to 90°, which can effectively impact and hinder the incoming flow. The eddy current generator is fixedly connected to the rotor and is arranged in an array along the radial direction at the same interval, with the orientation perpendicular to the rotor radius and parallel to the incoming flow direction, and is symmetrically distributed on the high-pressure side and the low-pressure side of the rotor, and is the same on the end face of each blade.

[0045] More specifically, the angle between the first side edge and the vertical direction is the sweep angle θ, where 0° < θ < 90°.

[0046] More specifically, the height of the triangular prism is denoted as h1, where 0.2 mm < h1 < 1 mm.

[0047] More specifically, both of the two incoming flow side faces in the triangular prism are straight faces or concave arc faces, and the backflow side face connected to the return flow groove 3 is only a concave arc face; the side face opposite to the first side edge is called the backflow side face.

[0048] More specifically, the first side edge adopts a swept streamline design, which can reduce the additional resistance of the eddy current generator 2; the swept structure causes the fluid in the boundary layer on the incoming flow face of the eddy current generator 2 to flow upward to the upper surface, resulting in a thicker boundary layer on the upper surface side and more kinetic energy loss, and it is easier to generate airflow separation.

[0049] More specifically, the height of the eddy current generator is less than the local boundary layer thickness, and at the same time, the clearance distance is expanded to a certain extent to avoid ice slag jamming during low-temperature startup.

[0050] 2. Return flow groove 3

[0051] The return flow groove 3 is a "wing-shaped" groove and is arranged on the end face of the cam rotor 1. The return flow groove 3 is arranged behind the eddy current generator 2 and gradually becomes shallower from the eddy current generator 2 backward.

[0052] More specifically, the smooth front end of the return groove 3 is aligned with the rear side of the eddy current generator 2, and the groove surface of the smooth front end of the return groove 3 is smoothly connected to the concave arc surface of the backflow side of the eddy current generator 2, forming a smoothly transitioning arc surface. This design facilitates the working medium flowing out of the return groove 3 to form a backflow through the concave arc surface of the eddy current generator 2.

[0053] More specifically, the width of the return groove 3 is equal to the width of the side surface opposite to the first side edge, denoted as w, where 1 mm < w < 5 mm.

[0054] More specifically, the total length between the return groove 3 and the eddy current generator 2 is denoted as l, where 1 mm < l < 5 mm.

[0055] 3. Flow guiding fin 4

[0056] The flow guiding fin 4 has an "airfoil" structure, and the flow guiding fin 4 is fixedly arranged in the return groove 3. A return groove flow channel is formed between the flow guiding fin 4 and the return groove 3; the profiles of the flow guiding fin 4 and the return groove 3 are of similar design, and the smooth front end of the flow guiding fin 4 faces the eddy current generator 2.

[0057] More specifically, since the flow guiding fin 4 adopts an "airfoil" structure design, the horizontal plane of the flow guiding fin 4 is the suction surface, and the streamlined surface is the pressure surface.

[0058] More specifically, the suction surface of the flow guiding fin 4 is higher than the end surface of the cam rotor 1, and the height difference is denoted as h2, where 0.1 mm < h2 < h1.

[0059] More specifically, the width of the flow guiding fin 4 is equal to the width of the backflow side surface opposite to the first side edge, denoted as w, where 1 mm < w < 5 mm.

[0060] Based on the above introduction of the structures of the eddy current generator 2, the return groove 3, and the flow guiding fin 4 in a single structural unit, the distribution of multiple flow damping units on the end surface of the cam rotor 1 will be introduced below.

[0061] First, for the convenience of describing the distribution of the structural units, in this application, a plane rectangular coordinate system is established with the center of the shaft hole 5 at the center of the cam rotor 1 as the origin, the long axis of the cam rotor 1 as the x-axis, and the short axis of the cam rotor 1 as the y-axis.

[0062] The cam rotor 1 is a symmetric structure about the x-axis / y-axis, and with the shaft hole 5 as the center, an arc is made with a radius R. Along this arc, at least one flow damping unit group is arranged on the end surface of the cam rotor 1, that is, 2 flow damping units symmetrically distributed about the x-axis are provided on this arc. This is because the leakage flow direction of the cam rotor 1 during circular motion is tangential to the circle, so each flow damping unit is perpendicular to the radius and parallel to the oncoming flow direction.

[0063] Combined with the attachedFigure 3 , in this embodiment, a total of 2 sets of flow damping units are arranged on the same circular arc, that is, there are 4 flow damping units symmetrically distributed about the x-axis on this circular arc, and the flow damping units on the same side face the same direction. During operation, the two flow damping units on the high-pressure side are both used to induce eddy currents to block the gap between the end face of the cam rotor and the cover plate, and the two flow damping units on the low-pressure side are used to impede the leakage flow by the backflow impact.

[0064] More specifically, the present application arranges a plurality of concentric circular arcs with equal intervals, and at least one set of flow damping units is arranged on each circular arc. In this embodiment, a total of 5 concentric circular arcs are arranged, and 2 sets of flow damping units are arranged on each circular arc.

[0065] More specifically, the interval between the concentric circular arcs is denoted as ΔR, and ΔR > 2w; in this embodiment, ΔR = 10 mm.

[0066] More specifically, a plurality of flow damping units in the present application are distributed in a fan-shaped area on the end face of the cam rotor 1. In this embodiment, a flow damping unit with a width w = 2 mm, a length l = 4 mm, and a height h1 = 0.9 mm is arranged every ΔR = 10 mm on the radii of 15° and 30°.

[0067] The working principle is described below in combination with the structural characteristics of the flow damping unit:

[0068] The flow damping unit on the high-pressure side is used to induce eddy currents to block the gap between the end face of the cam rotor and the cover plate. Specifically, under the action of pressure, the working medium on the high-pressure side flows to the low-pressure side, forms eddy currents after passing through the eddy current generator 2 on the high-pressure side, and uses the generated eddy currents to block the gap between the end face of the high-pressure side cam rotor and the cover plate to reduce the axial clearance leakage.

[0069] The flow damping unit on the low-pressure side is used to impede the leakage flow by the backflow impact. Specifically, the eddy currents generated on the high-pressure side continue to flow to the low-pressure side under the action of pressure. Since the suction surface of the guide fin 4 on the low-pressure side is higher than the end face of the cam rotor 1, the pressure surface of the guide fin 4 can guide the incoming flow into the return groove flow channel, and the working medium flowing out of the return groove flow channel will form a backflow impact on the end face of the low-pressure side cam rotor 1 under the action of the eddy current generator 2 to reduce the axial clearance leakage.

[0070] Embodiment 2

[0071] Based on the above hydrogen circulation pump rotor for improving axial clearance leakage, the present application also designs a hydrogen circulation pump for improving axial clearance leakage, in combination with Figure 4 This hydrogen circulation pump includes:

[0072] The pump body 7;

[0073] Two cam rotors 1 are arranged in the pump body 7, and a rotating shaft hole 5 is provided at the center of each cam rotor 1; a plurality of regularly distributed flow damping units are arranged on the end faces of each cam rotor 1.

[0074] Pump covers 6 and gearbox covers 9 are arranged at the upper and lower ends of the pump body 7.

[0075] Gears 8, each cam rotor 1 is equipped with a gear 8, and the gear 8 and the cam rotor 1 are connected by a rotating shaft and a transmission key to achieve power transmission.

[0076] More specifically, as Figure 4 shown, the gearbox cover 9, the pump cover 6 and the two ends of the pump body 7 are fixedly connected. The cam rotor 1 is located in the chamber composed of the gearbox cover 9, the pump cover 6 and the pump body 7, and is fixedly connected to the gear 8 in the gearbox through a rotating shaft. The eddy current generator 2, the return flow groove 3 and the guide fins 4 are regularly distributed on the two end faces of the cam rotor 1 as a flow damping unit.

[0077] In terms of spatial position, the flow damping unit is in the axial gap between the end face of the rotor 1 and the pump cover 6 and the gearbox cover 9, and is distributed on concentric circles centered on the rotating shaft hole 5 with a radius difference of ΔR>2w on the plane of the end face of the rotor 1. The leakage flow direction of the circular motion of the rotor 1 is tangential to the circle, so each flow damping unit is perpendicular to the radius and parallel to the incoming flow direction. A flow damping unit with a width w = 2mm, a length l = 4mm, and a height h1 = 0.9mm is arranged every ΔR = 10mm on the radii of 15° and 30°, and then symmetrically arranged about the X-axis, so that the two opposite flow damping units can respectively play the role of inducing eddy currents to block the axial gap and the return flow impact to hinder the leakage flow, and can play a role in both the forward and reverse rotations of the rotor 1. The distribution of the flow damping units on each blade end face of the rotor 1 is the same.

[0078] The above embodiments are only used to illustrate the design ideas and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made according to the principles and design ideas disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A hydrogen circulation pump rotor for improving axial clearance leakage, characterized in that, Comprising: A set of flow damping units arranged on both end faces of the cam rotor (1), the set of flow damping units being composed of 2 flow damping units symmetrically distributed about the long axis of the cam rotor (1); with the center of the cam rotor (1) as the center of a circle, the flow damping units are arranged along the tangent of a certain point on the arc of the circle at the center of the circle. The flow damping unit includes An eddy current generator (2), the eddy current generator (2) being a triangular prism, with one side edge facing the direction of the leakage incoming flow, and this side edge being called the first side edge; the three side edges and three side faces of the eddy current generator (2) all extend backward to form a swept-back triangular prism; both of the oncoming side faces of the eddy current generator (2) are straight faces or concave arc faces, and the backflow side face connected to the backflow groove (3) is a concave arc face; among the three side faces of the eddy current generator (2), the side face opposite to the first side edge is the backflow side face, the smooth front end of the backflow groove (3) is aligned with the backflow side face of the eddy current generator (2), and the groove surface of the smooth front end of the backflow groove (3) is smoothly connected to the concave arc face of the backflow side face of the eddy current generator (2) to form a smoothly transitioning arc surface. A backflow groove (3), the backflow groove (3) being a "wing-shaped" groove, the backflow groove (3) being arranged behind the eddy current generator (2) and gradually becoming shallower from the eddy current generator (2) backward. A guide fin (4), the guide fin (4) being of a "wing-shaped" structure, and the guide fin (4) being fixedly arranged in the backflow groove (3), with a backflow groove flow channel formed between the guide fin (4) and the backflow groove (3); the upper surface of the guide fin (4) is higher than the upper opening of the backflow groove (3).

2. The hydrogen circulation pump rotor for improving axial clearance leakage according to claim 1, characterized in that, A plurality of concentric arcs are set with the center of the cam rotor (1) as the center, and the adjacent arcs are arranged at equal intervals, and the interval is denoted as ∆ R , ∆ R > 2 w , w is the width of the eddy current generator (2).

3. A hydrogen circulation pump rotor for improving axial clearance leakage according to claim 2, characterized in that, At least one set of flow damping units is arranged on the arc with the center of the cam rotor (1) as the center of a circle.

4. A hydrogen circulation pump rotor for improving axial clearance leakage according to claim 1, characterized in that, Taking the long axis of the cam rotor (1) as the boundary, the flow damping units on the same side of the cam rotor (1) face the same direction, and the flow damping units on both sides are symmetrically distributed about the long axis of the cam rotor (1).

5. A hydrogen circulation pump rotor for improving axial clearance leakage according to claim 1, characterized in that, The included angle between the first side edge and the vertical direction is the sweep angle θ , taking 0° < θ < 90°.

6. A hydrogen circulation pump rotor for improving axial clearance leakage according to claim 1, characterized in that, The widths of the reflux tank (3), the guide fins (4) and the eddy current generator (2) are equal, taking 1 mm< w <5 mm.

7. A hydrogen circulation pump rotor for improving axial clearance leakage according to claim 1, characterized in that, The distance by which the upper surface of the flow guiding fin (4) is higher than the end face of the cam rotor (1) is denoted as h 2 , taking 0.1 mm < h 2 < h 1, h where 1 is the height of the eddy current generator (2), taking 0.2 mm < h 1 < 1 mm.

8. A hydrogen circulation pump for improving axial clearance leakage, characterized in that, Comprising: A pump body (7); 2 hydrogen circulation pump rotors for improving axial clearance leakage as described in claim 1 arranged in the pump body (7), with a rotating shaft hole (5) provided at the center of each cam rotor (1); At least one set of flow damping units arranged on the end face of each cam rotor (1); Pump covers (6) and gearbox covers (9) arranged at the upper and lower ends of the pump body (7); Gears (8), each cam rotor (1) being equipped with a gear (8), and the gear (8) being fixedly connected to the cam rotor (1) through a rotating shaft.

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