Impeller with vortex suppression and separation function, compressor, air conditioner and automobile

Abstract

The present invention discloses an impeller, a compressor, an air conditioner and a car with vortex elimination, suppression and separation functions. The impeller described herein includes a hub, blades and a wheel cover. The outlet edge of the main flow channel between two adjacent blades is provided with at least one aerofoil blade, and the two ends of the aerofoil blade are a sheet-like body composed of streamlined surfaces, and the direction in which the aerofoil blade is arranged is the same as the direction of the blade. The aerofoil blades arranged in the main flow channel form an aerofoil-shaped diversion channel inside the impeller to eliminate the formation of vortices and suppress airflow separation, reduce losses, and improve the aerodynamic efficiency of the compressor. By improving the flow guidance effect inside the impeller and making the airflow angle uniform, the problem of matching the direction of the airflow at the impeller outlet and the diffuser inlet is optimized, the exhaust noise of the compressor is effectively reduced, and the efficiency and comfort of the fuel cell system are comprehensively improved.

Description

Technical Field

[0001] The invention relates to fluid conveying equipment, in particular to an impeller with vortex elimination, suppression and separation functions, a compressor with the impeller, an air conditioner with the compressor and a car with the compressor. Background Art

[0002] As a general power source, air compressors are widely used in machinery, automobiles, medical treatment, food, electricity, building materials, petroleum, chemical industry and military industry. According to the different compressor types, centrifugal air compressors, screw air compressors, scroll air compressors and so on are common. In terms of new energy, hydrogen fuel cell vehicles have high power performance, fast hydrogenation and long driving range, which is the most strategic breakthrough for new energy vehicles in the 21st century. The compressor provides a high-pressure gas source for the fuel cell system. Compared with screw compressors and scroll compressors, centrifugal compressors can provide a gas source with a higher pressure ratio, which can significantly improve the power density and overall performance of the stack. The working principle of the centrifugal compressor is: after power is turned on, the high-speed motor drives the impeller to compress the incoming air and make it high-pressure air. Therefore, the impeller is the "heart" of the air compressor, which continuously provides a high-pressure gas source for the fuel cell system, so the working efficiency of the impeller directly affects the working efficiency of the entire fuel cell system. The loss of the air flow after passing through the impeller is roughly divided into four parts: friction loss, separation loss, secondary flow loss and wake loss. Friction loss is caused by the friction between the gas and the wall and is inevitable; separation loss is mainly due to the separation of the boundary layer, which produces vortices, resulting in reverse flow of the airflow and causing energy loss; secondary flow loss is mainly due to the pressure difference on the wall. The gas flows from the working surface to the non-working surface, and the direction is perpendicular to the fluid in the mainstream area, causing energy loss; trail loss is mainly due to the certain thickness of the impeller trailing edge. When the gas flows out of the impeller flow channel, the flow area suddenly expands, causing energy loss caused by vortices.

[0003] The automotive fuel cell compressor is mainly used in small cars or commercial vehicles. It has a small size and light weight, resulting in relatively few impellers. Therefore, the impeller loss will greatly reduce the working efficiency of the compressor. Therefore, it is necessary to further limit the flow loss inside the impeller to improve the efficiency of the compressor. As mentioned above, friction loss and wake loss are inevitable, and it is difficult to further reduce them. Separation loss and secondary flow loss account for the main part of energy loss. Therefore, how to further optimize the internal flow channel of the impeller to limit the separation of the boundary layer and the formation of vortices.

[0004] Therefore, how to overcome the defect that the boundary layer of the impeller flow passage of the existing compressor is easily separated and forms a vortex is a problem that needs to be solved urgently in the industry. Summary of the invention

[0005] In order to solve the problem that the boundary layer of the impeller flow channel of the existing compressor is easy to separate and form vortices, the present invention provides an impeller that can eliminate the vortex inside the flow channel and inhibit air separation, namely, a centrifugal compressor with the impeller, an air conditioner with the compressor and a car with the compressor, thereby eliminating the formation of vortices, reducing separation losses and improving the aerodynamic efficiency of the air compressor.

[0006] The present invention provides an impeller with vortex elimination, suppression and separation functions, comprising a hub, blades and a wheel cover. The outlet edge of the main flow channel between two adjacent blades is provided with at least one aerofoil blade, the two ends of the aerofoil blade are a sheet body composed of streamlined curved surfaces, and the direction in which the aerofoil blade is arranged is the same as the direction of the blade.

[0007] Preferably, the airfoil blades are arranged on the inner surface of the wheel cover and / or on the inner surface of the wheel hub.

[0008] Preferably, the ratio of the height H of the airfoil blade to the impeller outlet height B is H / B=0.025~0.4.

[0009] Preferably, in the main flow channel, the inlet position of the airfoil blade is such that the ratio of the inlet installation diameter D3 to the impeller diameter D2 is D3 / D2=0.6-0.7.

[0010] Preferably, the outlet position of the airfoil blade is such that the ratio of the outlet installation diameter D4 to the impeller diameter D2 is D4 / D2=0.8~0.9.

[0011] Preferably, the airfoil blade is thick at one end at the gas inlet and thin at one end at the gas outlet.

[0012] Preferably, the two sides of the airfoil blade are parallel side surfaces, and the two parallel side surfaces are connected to the streamlined curved surfaces at both ends to form the airfoil blade.

[0013] Preferably, both sides of the airfoil blade are outwardly convex curved side surfaces, and the outwardly convex curved side surfaces on both sides are correspondingly and smoothly connected to the streamlined curved surfaces at both ends.

[0014] Preferably, a pair of airfoil blades are arranged in parallel on the inner surface of the wheel cover or the wheel hub; or, an airfoil blade is arranged on each of the inner surfaces of the wheel cover and the wheel hub in double rows and in parallel.

[0015] The present invention provides a compressor, which comprises the impeller with the vortex elimination, suppression and separation function.

[0016] The present invention provides an air conditioner, which comprises the compressor.

[0017] The invention provides a car, comprising the compressor.

[0018] The present invention provides at least one airfoil blade in each main flow channel of the impeller, so that an airfoil drainage channel is formed inside the impeller to eliminate the formation of vortices and inhibit airflow separation, reduce losses, and improve the aerodynamic efficiency of the compressor. By improving the flow guidance effect inside the impeller, the airflow angle is uniform, and the direction matching problem of the airflow at the impeller outlet and the diffuser inlet is optimized, the exhaust noise of the compressor is effectively reduced, and the efficiency and comfort of the fuel cell system are comprehensively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a three-dimensional schematic diagram of an impeller embodiment of the present invention;

[0020] Figure 2 A front view of an impeller embodiment of the present invention with the wheel cover removed;

[0021] Figure 3 is a three-dimensional schematic diagram of an airfoil blade embodiment of the present invention;

[0022] Figure 4 Schematic diagram of the installation position of the single-piece airfoil blade of the present invention

[0023] Figure 5 The tandem airfoil blade installation structure of the present invention

[0024] Figure 6 It is a schematic structural diagram of a compressor with the impeller of the present invention.

[0025] In the figure: 1—locking screw; 2—impeller; 3—volute; 4—diffuser; 5—barrel; 6—front axial bearing; 7—thrust plate; 8—rear axial bearing; 9—front bearing seat; 10—front radial bearing; 11—water cooling jacket; 12—spiral cooling channel; 13—motor stator; 14—motor shaft; 15—rear radial bearing; 16—rear bearing seat;

[0026] 20-hub, 21-blade, 22-wheel cover, 23-impeller outlet, 24-impeller inlet, 26-airfoil blade, 27-pressure surface,

[0027] 28-suction surface, 29-outer end of the airfoil blade. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0029] like Figure 1 , Figure 2As shown in the figure, an embodiment of an impeller with vortex elimination, suppression and separation function provided by the present invention comprises a hub 20 and a wheel cover 22, and blades 21 arranged between the hub and the wheel cover. The main flow channel of the impeller 2 is composed of two adjacent blades, the hub, the wheel cover, and the impeller outlet 23 and the impeller inlet 24. The present invention is provided with at least one airfoil blade 26 at the outlet edge of the main flow channel of the impeller. Figure 3 The airfoil blade 26 is a sheet-like body with streamlined curved surfaces at both ends. The front and rear sides of the sheet-like body are parallel. The distance between the two parallel sides is the height H of the airfoil blade. The direction in which the airfoil blade 26 is set is the same as the direction of the blade 21. As needed, the airfoil blade can be set on the inner surface of the wheel cover 22 or on the inner surface of the hub 20, or the airfoil blades can be staggered on the inner surfaces of the wheel cover 22 and the hub 20. In this embodiment, a piece of airfoil blade 26 is set on the inner surface of the wheel cover, that is, the top surface of the airfoil blade is fixedly connected to the inner surface of the wheel cover, and the streamlined and smooth ends of the airfoil blade are set in the same direction as the blade 21 (please read Figure 2 Schematic position of the middle airfoil blade). In order to maintain a better airflow field, the height H of the airfoil blade 26 is associated with the impeller outlet height B, and the ratio of the two is limited to H / B=0.025~0.4. The impeller outlet height B is the axial distance between the hub and the wheel cover. The partition wall formed between the airfoil blades can effectively block the formation of vortices, accelerate the flow velocity at the relative position, and limit the separation of the impeller outlet position-airflow. Depending on the actual position where the vortex is formed, the height H of the airfoil blade 26 can also extend from the wheel cover 22 to the hub 20. The airfoil blade 26 is arranged in the main flow channel, has a gap with the adjacent blade 21, and is also a certain distance from the outer circle of the impeller 2. Such installation forms an airfoil drainage channel in the main flow channel of the impeller. As shown Figure 4As shown, the gas inlet position (inner end) of the general airfoil blade 26 is the position of one end of the airfoil blade close to the center of the impeller 2. The ratio of the inlet installation diameter D3 to the impeller diameter D2 is controlled to be D3 / D2=0.6~0.7. D3 is the diameter of the circle where the gas inlet end (inner end) of each airfoil blade is located. Because the gas will first separate near the wheel cover after the turn, the separation development can be suppressed here. Due to the addition of airfoil blades, a wake vortex will be formed at the outlet position, so the airfoil blade outlet is separated from the impeller outlet by a distance, so that the tail airflow can be fully uniform, the airflow outlet airflow angle is optimized, the airflow pulsation is reduced, and the noise is reduced. The gas outlet position (outer end) of the airfoil blade 26, that is, the position of one end of the airfoil blade close to the outer circle of the impeller, controls the ratio of the outlet installation diameter D4 to the impeller diameter D2 to be D4 / D2=0.8~0.9. D4 is the diameter of the circle where the gas outlet end (outer end) of each airfoil blade is located. This ensures that the gas can be mixed to a certain extent at the trailing edge, ensuring that the gas entering the diffuser inlet is relatively uniform. In order to reduce the loss of the trailing edge of the airfoil blade, the tail, the outer end 29 of the airfoil blade 26, needs to be thinned (such as Figure 3 As shown in FIG. 1 ), the airfoil blade can also be set to a shape with a thick head at the gas inlet and a thin tail at the gas outlet. As required, the two sides of the airfoil blade can be designed as parallel straight surfaces, and then connected to the streamlined curved surfaces at both ends to form an airfoil blade; as shown in FIG. Figure 3 As shown in FIG. 1 , the two sides of the airfoil blade can also be designed as convex curved sides, and then connected to the streamlined curved surfaces at both ends. Figure 5 As shown, the airfoil blades 26 can be arranged in a double row parallel state according to the size of the blade flow channel separation, that is, one airfoil blade can be arranged on each of the inner surfaces of the wheel cover 22 and the wheel hub 20; or a pair of airfoil blades can be arranged in parallel on the wheel cover or the wheel hub.

[0030] like Figure 2As shown, the impeller 2 rotates counterclockwise, and the working surface of the blade 21 facing the counterclockwise rotation direction of the impeller 2 is the pressure surface 27, that is, the "back" of the blade 21, and the surface opposite to the pressure surface 27 of the blade is the suction surface 28. The gas is sucked in from the impeller inlet 24 and discharged from the impeller outlet 23. When the gas passes through the surface of the blade 21 and other parts, its speed will gradually decrease due to friction. Since the impeller has a pressure diffusion effect, it will cause the boundary layer (a thin gas adhesion layer formed on the surface of the blade, the wheel cover, and the hub) to flow in the opposite direction, thereby reducing the flow area of ​​the main channel and failing to play a pressure diffusion role. At the same time, due to the speed difference between the working surface 27 and the suction surface 28 of the blade, a flow in the direction perpendicular to the impeller axis will be generated on the hub surface, which is easy to form a vortex and disturb the flow field in the mainstream area. In order to solve the separation loss and vortex formation, an airfoil blade 26 of a suitable flow channel is added to each main flow channel of the impeller 2. The direction of the airfoil blade is the same as that of the main flow channel blade. When the airflow turns along the wheel cover and enters the diffuser inlet, it can be guided to suppress or prevent the formation of vortex. There is a gap between the airfoil blade 26 and the adjacent blade 21, and there is also a certain distance from the outer circle of the impeller. The cross-sectional shape of the impeller inlet is similar to an ellipse, which is narrow near the hub 20 and wide near the wheel cover 22. Such installation forms an airfoil diversion flow channel in the main flow channel of the impeller to eliminate the formation of vortex and suppress airflow separation, reduce losses, and improve the aerodynamic efficiency of the compressor. By improving the diversion effect inside the impeller, the airflow angle is uniform, and the direction matching problem of the airflow at the impeller outlet and the diffuser inlet is optimized, the compressor exhaust noise is effectively reduced, and the efficiency and comfort of the fuel cell system are comprehensively improved.

[0031] The present invention also provides a centrifugal compressor, which includes the impeller with vortex elimination and separation function. Figure 6 As shown, the compressor comprises: a locking screw 1, an impeller 2 with vortex suppression and separation function, a volute 3, a diffuser 4, a barrel 5, a front axial bearing 6, a thrust plate 7, a rear axial bearing 8, a front bearing seat 9, a front radial bearing 10, a water cooling jacket 11, a spiral cooling channel 12, a motor stator 13, a motor shaft 14, a rear radial bearing 15, and a rear bearing seat 16. The impeller 2 is the core part of the air compressor. When working, the impeller 2 compresses the compressor inlet airflow to make it a high-pressure airflow, which is finally transported to the hydrogen fuel cell reactor to improve the fuel efficiency of hydrogen.

[0032] like Figure 6As shown, the locking screw 1 is a solid, rotating part with an external thread, which is connected to the motor shaft 14 through the thread to tighten the impeller 2. The diffuser 4 is a rotating part, which is a common structure in turbine machinery. Its left end face and the corresponding right end face of the volute 3 form a pressure diffusion channel, so that the outlet airflow of the impeller 2 can obtain a pressure diffusion effect and increase the pressure. The cylinder 5 is a cylindrical part, generally cast, and plays a supporting and protective role. A water cooling jacket 11 is embedded in the cylinder, and a spiral cooling channel 12 is formed with the water cooling jacket 11. The front axial bearing 6 and the rear axial bearing 8, the front radial bearing 10 and the rear radial bearing 15 are air-type gas bearings, whose working medium is air. When working, an air film is formed to suspend the thrust plate 7, which rotates with the motor shaft 14. The front bearing seat 9 and the rear bearing seat 16 are hollow, rotating parts that provide support for the gas bearing. The motor stator 13 is a rotating part, mainly composed of a stator core and a stator winding. The motor shaft 14 is a shaft-like, solid part. The locking screw 1, the impeller 2, the thrust plate 7, and the motor shaft 14 form a rotor. When working, the motor stator 13 generates a magnetic field, and the rotor performs high-speed rotation under the action of the electromagnetic field.

[0033] The present invention provides a car having the compressor provided by the present invention. The present invention also provides an air conditioner having the compressor provided by the present invention.

[0034] The above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An impeller with vortex suppression and separation functions, comprising a hub, blades and a wheel cover, characterized in that: At least one airfoil blade is provided at the outlet edge of the main flow channel between adjacent blades, and both ends of the airfoil blade are a sheet-like body composed of streamlined curved surfaces, and the direction in which the airfoil blade is arranged is the same as the direction of the blade, wherein: The ratio of the height H of the airfoil blade to the impeller outlet height B is H / B=0.025~0.4; The inlet position of the airfoil blade is set to the ratio of the inlet installation diameter D3 to the impeller diameter D2: D3 / D2=0.6~0.7; The outlet position of the airfoil blade is set to the ratio of the outlet installation diameter D4 to the impeller diameter D2: D4 / D2=0.8~0.

9.

2. The impeller with vortex elimination and separation function as claimed in claim 1, characterized in that: The airfoil blades are arranged on the inner surface of the wheel cover and / or the inner surface of the wheel hub.

3. The impeller with vortex elimination and separation function as claimed in claim 1, characterized in that: The airfoil blade is in a shape where one end of the gas inlet is thick and one end of the gas outlet is thin.

4. The impeller with vortex elimination and separation function as claimed in claim 1, characterized in that: The two sides of the airfoil blade are parallel side surfaces, and the two parallel side surfaces are connected correspondingly with the streamlined curved surfaces at both ends to form the airfoil blade.

5. The impeller with vortex elimination and separation function as claimed in claim 1, characterized in that: The two sides of the airfoil blade are outwardly convex curved side surfaces, and the outwardly convex curved side surfaces on the two sides are smoothly connected to the streamlined curved surfaces at both ends.

6. The impeller with vortex elimination and separation function as claimed in claim 1, characterized in that: A pair of airfoil blades are arranged in parallel on the inner surface of the wheel cover or the wheel hub; or, an airfoil blade is arranged on each of the inner surfaces of the wheel cover and the wheel hub, in a double row and parallel state.

7. A compressor, characterized in that: It comprises an impeller with vortex elimination, suppression and separation function as described in any one of claims 1 to 6.

8. An air conditioner, characterized in that: Comprising the compressor of claim 7.

9. A car, characterized in that: Comprising the compressor of claim 7.

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