Blade, impeller for air compressor and air compressor

Abstract

The application provides a blade for an air compressor, the blade comprising: a positive pressure surface configured to bear a positive pressure of air when the blade rotates; a negative pressure surface configured to bear a negative pressure of air when the blade rotates, and the negative pressure surface is arranged on the opposite side of the positive pressure surface; and a side surface configured to connect the positive pressure surface and the negative pressure surface; wherein at least the side surface comprises a non-smooth surface structure. The application also provides an impeller comprising the foregoing blade and an air compressor comprising the foregoing impeller. According to the application, the efficiency of the air compressor can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air compressors, and in particular to a blade for an air compressor, an impeller comprising the blade, and an air compressor. BACKGROUND

[0002] Air compressors have been widely used in various industries as air supply devices. For example, electric air compressors are used as air sources for braking, air sources for turbochargers, or air sources for fuel cells in vehicles.

[0003] An air compressor generally comprises a housing, an impeller, and a driving device (e.g., an electric motor). The impeller rotates at high speed under the driving of the driving device, so that the air entering the housing is compressed along with the rotation of the impeller. Since the rotational speed of the impeller is high, up to hundreds of thousands of revolutions per minute, the high-speed movement of the impeller will cause complex air movement patterns near the blades. Specifically, at the surface of the blade, the air in contact with the smooth surface of the blade is prone to form turbulent flow due to the viscous effect, resulting in energy loss and reducing the efficiency of the air compressor.

[0004] Various solutions have been proposed in the prior art to improve the components of air compressors, such as changing the curve shape and angle distribution of the blades, changing the structure of the positive pressure surface and the negative pressure surface of the blades, etc., but the problem of reducing turbulent loss has not been completely solved. SUMMARY

[0005] The present application aims to provide an improved blade for an air compressor, an impeller comprising the blade, and an air compressor comprising the impeller, to reduce energy loss and improve efficiency.

[0006] The concept of the present application mainly comes from numerical simulation and analog calculation of turbulent loss at the blade of the existing air compressor, and observation of the topography structure of the outer surface of the elytra of Coleoptera (e.g., dung beetle, etc.).

[0007] Generally, manufacturers or designers try to reduce the turbulent loss generated by the pressure surface (i.e., the surface of the blade that bears the positive pressure of the air when the blade rotates) and the suction surface (i.e., the surface of the blade that bears the negative pressure of the air when the blade rotates, which is arranged on the opposite side of the pressure surface) of the blade, so the design is mostly focused on the pressure surface and the suction surface of the blade. However, the applicant found that not only the pressure surface and the suction surface of the blade generate turbulent loss, but also the side surface (i.e., the surface of one side in the thickness direction of the blade, which is substantially perpendicular to the pressure surface and the suction surface) connecting the pressure surface and the suction surface also generates a large amount of turbulent loss through numerical simulation and simulation calculation of the blade. Therefore, reducing the turbulent loss of the side surface of the blade can further improve the efficiency of the air compressor. In order to reduce the turbulent loss of the side surface of the blade, the applicant studies the morphology of the outer surface of the elytra of a coleopteran (e.g., a dung beetle), and finds that the non-smooth surface structure of the outer surface of the elytra can effectively reduce the viscous effect of the side surface of the blade when the blade moves at high speed, thereby reducing the turbulent loss and improving the efficiency of the air compressor.

[0008] To this end, according to an aspect of the present application, a blade for an air compressor is provided, the blade comprising: a pressure surface configured to bear a positive pressure of air when the blade rotates; a suction surface configured to bear a negative pressure of air when the blade rotates, and the suction surface is arranged on the opposite side of the pressure surface; and a side surface configured to connect the pressure surface and the suction surface; wherein at least the side surface comprises a non-smooth surface structure.

[0009] According to an embodiment of the present application, the blade comprises a main blade and a sub blade, and the length of the non-smooth surface structure of the main blade in the radial direction is greater than the length of the non-smooth surface structure of the sub blade in the radial direction.

[0010] According to an embodiment of the present application, the blade further comprises an outer edge surface, which is the radially outermost surface of the blade, and the non-smooth surface structure of the blade is arranged in a portion of the side surface close to the outer edge surface.

[0011] According to an embodiment of the present application, the non-smooth surface structure comprises a pit structure, a groove structure, or a combination thereof.

[0012] According to an embodiment of the present application, when the non-smooth surface structure comprises a pit structure, the pit structure is an array formed by a plurality of pits, and the spacing between adjacent pits gradually decreases outwardly along the radial direction; and when the non-smooth surface structure comprises a groove structure, the groove structure comprises a plurality of grooves, and the spacing between adjacent grooves gradually decreases outwardly along the radial direction.

[0013] According to an embodiment of the present application, the cross-sectional shape of the recess is partially circular or partially elliptical; and the cross-sectional shape of the groove is partially circular or partially elliptical.

[0014] According to an embodiment of the present application, the depth of the recess is 5-100 microns, and the length and / or width is 10-400 microns; and the depth of the groove is 5-100 microns, and the width is 10-400 microns.

[0015] According to another aspect of the present application, there is provided an impeller for an air compressor, wherein the impeller comprises: a hub configured to be coupled with a driving device; and a blade as described above, wherein the blade is fixedly coupled with or integrated with the hub.

[0016] According to an embodiment of the present application, the impeller further comprises an end plate disposed perpendicularly to the direction of the rotation axis of the impeller, and fixedly coupled with or integrated with the hub, wherein the blade is fixedly coupled with or integrated with the end plate.

[0017] According to yet another aspect of the present application, there is provided an air compressor, wherein the air compressor comprises: a driving device; and an impeller as described above, wherein the driving device is configured to drive the impeller to rotate.

[0018] Due to the non-smooth structure of the side surface of the blade, the blade, the impeller and the air compressor provided by the present application can reduce the energy loss caused by the turbulence near the side surface of the blade, thereby further improving the efficiency of the air compressor. BRIEF DESCRIPTION OF DRAWINGS

[0019] Exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the embodiments described below are merely given by way of explanation of the present application, but not intended to limit the scope of the present application, and that the present application is defined only by the appended claims. In the drawings:

[0020] Figure 1 is a schematic perspective view showing an impeller for an air compressor according to an embodiment of the present application;

[0021] Figure 2 is a schematic perspective view showing a blade for an air compressor according to an embodiment of the present application. Figure 1

[0022] Figure 3 is a schematic perspective view showing an impeller for an air compressor according to an embodiment of the present application; DETAILED DESCRIPTION

[0023] ​Preferred embodiments of this application are described in detail below with reference to examples. In the embodiments of this application, a centrifugal air compressor and its blades and impeller are used as examples for description. However, those skilled in the art should understand that these exemplary embodiments do not imply any limitation on this application. Furthermore, features in the embodiments of this application can be combined with each other unless otherwise specified. In different drawings, the same components are represented by the same reference numerals, and other components are omitted for brevity, but this does not mean that the blades, impellers, and air compressors of this application cannot include other components. It should be understood that the dimensions, proportions, and number of components in the drawings are not intended to limit this application.

[0024] In this document, unless otherwise stated, “axial” means the direction of extension of the axis of rotation of the blades or impeller of the air compressor about which it rotates, “radial” means the radial direction relative to the axis of rotation, and “circumferential” means the circumferential direction relative to the axis of rotation, that is, the direction around the axis of rotation.

[0025] In this document, unless otherwise stated, “positive pressure” means pressure greater than normal pressure, and “negative pressure” means pressure less than normal pressure.

[0026] The following reference Figures 1-3 To describe blades and impellers for an air compressor according to embodiments of this application. Figure 1 An impeller for an air compressor according to an embodiment of the application is schematically shown. Figure 2 It is shown Figure 1 A schematic enlarged view of region A in the diagram. Figure 3 A blade for an air compressor according to an embodiment of this application is schematically shown.

[0027] It should be noted that the air compressor can be of any type; a centrifugal air compressor will be used as an example here. Although not shown in the accompanying drawings, it is known that an air compressor typically includes a housing, an impeller, and a drive unit. The impeller is housed within the housing and fixedly connected to the drive unit. When the drive unit rotates the impeller, the air entering the housing undergoes both circumferential and radial motion under the impeller's high-speed rotation. The impeller's action increases the air's pressure and kinetic energy. After exiting the impeller and entering the diffuser, the air velocity gradually decreases, the pressure continuously increases, and then the air exits the compressor and enters a storage container or piping network. Figure 1 In the case of the impeller 100 of the centrifugal air compressor shown, air enters axially and exits radially.

[0028] like Figures 1-3As shown, the impeller 100 for an air compressor according to the present application includes a hub 60 configured to be coupled with a driving device (not shown), and blades 10 fixedly coupled with or integral with the hub 60, for example, through the roots 17 of the blades 10. In addition, in the impeller 100 of the centrifugal air compressor as shown, an end plate 50 is also included, which is disposed perpendicular to the direction of the rotation axis of the impeller 100, and is fixedly coupled with or integral with the hub 60, wherein the blades 10 are also fixedly coupled with or integral with the end plate 50, for example, through the roots 17 of the blades 10. Figure 1 As shown, the impeller 100 for an air compressor according to the present application includes a hub 60 configured to be coupled with a driving device (not shown), and blades 10 fixedly coupled with or integral with the hub 60, for example, through the roots 17 of the blades 10. In addition, in the impeller 100 of the centrifugal air compressor as shown, an end plate 50 is also included, which is disposed perpendicular to the direction of the rotation axis of the impeller 100, and is fixedly coupled with or integral with the hub 60, wherein the blades 10 are also fixedly coupled with or integral with the end plate 50, for example, through the roots 17 of the blades 10.

[0029] The blades 10 for an air compressor according to the present application include main blades 11 and secondary blades 12, both of which have similar structures, but the sizes and shapes can be different. The main blades 11 and the secondary blades 12 are arranged uniformly along the circumferential direction of the impeller 100, and the secondary blades 12 are located between two adjacent main blades 11. Of course, the impeller 100 can also have only main blades 11 without secondary blades 12. The specific structure of the blades 10 will be described below by taking the main blades 11 as an example, and the repeated description of the similar structure of the secondary blades 12 will be omitted. Reference is made to Figure 3 The main blade 11 includes a pressure face 13 configured to bear the positive pressure of air when the main blade 11 rotates, a suction face 14 configured to bear the negative pressure of air when the main blade 11 rotates, and the suction face 14 is disposed on the opposite side of the pressure face 13, and a side face 15 configured to connect the pressure face 13 and the suction face 14. In other words, the side face 15 is the surface of one side of the main blade 11 in the thickness direction. According to the embodiment of the present application, in the main blade 11, at least the side face 15 includes a non-smooth surface structure 16. In this way, when the main blade 11 operates at high speed, the viscous effect at the side face 15 of the main blade 11 can be reduced, so that the turbulent loss can be reduced, and the efficiency of the air compressor can be improved.

[0030] According to the embodiment of the present application, in addition to the side face 15 of the main blade 11 being provided with the non-smooth surface structure 16, the pressure face 13 and / or the suction face 14 of the main blade 11 can also be provided with the non-smooth surface structure 16, so as to further reduce the turbulent loss.

[0031] It should be noted that the secondary blade 12 also has a pressure face, a suction face and a side face as described above, and at least the side face is provided with a non-smooth surface structure. In particular, as Figure 3 As shown, considering the difference in airflow borne by the main blade 11 and the secondary blade 12, the length L1 of the non-smooth surface structure of the main blade 11 in the radial direction is greater than the length L2 of the non-smooth surface structure of the secondary blade 12 in the radial direction, so as to focus on reducing the turbulent loss on the main blade 11.

[0032] The main blade 11 also comprises an outer edge surface 18, which is the radially outermost surface of the main blade 11, and the non-smooth surface structure 16 of the main blade 11 is arranged in a portion of the side surface 15 close to the outer edge surface 18. It is found in the numerical simulation process that the possibility of greater turbulent loss occurs in the portion of the side surface 15 close to the outer edge surface 18, and therefore the non-smooth surface structure 16 can be arranged close to the outer edge surface 18. Of course, the outer edge surface 18 can also be provided with the non-smooth surface structure as described above to further improve the flow field structure of the air flow.

[0033] The non-smooth surface structure 16 is a structure designed by bionics referring to the outer surface of the elytra of a dung beetle. The pit structure and the groove structure are the topographic structures of different parts on the outer surface of the elytra of a dung beetle, which can change the gas flow field flowing through the vicinity of the structure.

[0034] According to an embodiment of the present application, as shown in Figure 2 and 3 , the non-smooth surface structure 16 is a pit structure, wherein the pit structure is an array of a plurality of pits, and the spacing between adjacent pits gradually decreases outwardly along the radial direction. That is, outwardly along the radial direction, the arrangement of pits is more and more dense to correspond to the distribution of turbulent loss on the blade side surface 15.

[0035] According to another embodiment of the present application, the non-smooth surface structure 16 can also be a groove structure (not shown), wherein the groove structure comprises a plurality of grooves, and the spacing between adjacent grooves gradually decreases outwardly along the radial direction. Similarly, outwardly along the radial direction, the arrangement of grooves is more and more dense to correspond to the distribution of turbulent loss on the blade side surface 15.

[0036] Alternatively, the non-smooth surface structure 16 can also be a combination of the pit structure and the groove structure.

[0037] According to the working parameters of the blade, the pit structure and the groove structure can also have different arrangements, such as uniform arrangement along the radial direction, random arrangement along the radial direction, or more and more sparse outwardly along the radial direction. It should be pointed out that the grooves in the groove structure can be arranged in parallel with each other, or can intersect or converge with each other.

[0038] The cross-sectional shape of the aforementioned pits can be partially circular or partially elliptical, and the cross-sectional shape of the aforementioned grooves can also be partially circular or partially elliptical to facilitate the flow of the boundary layer. It should be understood that the pits and the grooves can also have other cross-sectional shapes, such as triangular, rectangular, trapezoidal, etc.

[0039] After ANSYS simulation and finite element calculation, the depth of the concave pits can be 5-100 microns, the length and / or width can be 10-400 microns, and the depth of the grooves can be 5-100 microns and the width can be 10-400 microns. Of course, according to different blade sizes and rotational speeds, etc., the parameters of the concave pits and grooves can also be adjusted.

[0040] In another embodiment of the present application, the length of the non-smooth surface structure of the secondary blade 12 can also be greater than or equal to the length of the non-smooth surface structure of the primary blade 11, or can even not have a non-smooth surface structure.

[0041] According to the embodiments of the present application, the non-smooth surface structure of the blade can be formed by mechanical processing (e.g., laser processing), chemical etching, etc.

[0042] The present application has been described in detail above with reference to specific embodiments. It is apparent, however, that the above-described embodiments and examples are illustrative only and not restrictive of the present application. For example, the present application has been described above with reference to a blade and an impeller for a centrifugal air compressor as a preferred embodiment, but the present application can be applied not only to a centrifugal air compressor, but also to an axial air compressor or other fluid machinery having a high-speed rotating blade. Various modifications or changes can be made to the present application by those skilled in the art without departing from the spirit of the present application, and such modifications or changes are not excluded from the scope of the present application.

Claims

1. A blade (10) for an air compressor, the blade (10) comprising: a positive pressure surface (13) configured to bear positive pressure of air when the blade (10) rotates; a negative pressure surface (14) configured to bear negative pressure of air when the blade (10) rotates, and the negative pressure surface (14) is disposed on the opposite side of the positive pressure surface (13); and a side surface (15) configured to connect the positive pressure surface (13) and the negative pressure surface (14); wherein at least the side surface (15) comprises a non-smooth surface structure (16); wherein the non-smooth surface structure (16) comprises a dimple structure or a groove structure, when the non-smooth surface structure (16) comprises the dimple structure, the dimple structure is an array of a plurality of dimples, and a spacing between adjacent dimples gradually decreases outwardly along a radial direction, so that the arrangement of the dimples is increasingly dense; and when the non-smooth surface structure (16) comprises the groove structure, the groove structure comprises a plurality of grooves, and a spacing between adjacent grooves gradually decreases outwardly along the radial direction, so that the arrangement of the grooves is increasingly dense; wherein the blade (10) comprises a main blade (11) and a sub-blade (12), a length of the non-smooth surface structure of the main blade (11) in the radial direction is greater than a length of the non-smooth surface structure of the sub-blade (12) in the radial direction.

2. Blade (10) according to claim 1, characterized in that The blade (10) further comprises an outer edge surface (18), the outer edge surface (18) is a radially outermost surface of the blade (10), and the non-smooth surface structure (16) of the blade (10) is disposed in a portion of the side surface (15) close to the outer edge surface (18).

3. The blade (10) according to claim 1, characterized in that A cross-sectional shape of the dimple is partially circular or partially elliptical; and a cross-sectional shape of the groove is partially circular or partially elliptical.

4. The blade (10) according to claim 1, characterized in that A depth of the dimple is 5-100 microns, and a length / width is 10-400 microns; and a depth of the groove is 5-100 microns, and a width is 10-400 microns.

5. An impeller (100) for an air compressor, characterized by, The impeller (100) comprises: a hub (60) configured to be coupled with a driving device; and The blade (10) according to any one of claims 1 to 4, wherein the blade (10) is fixedly coupled with or integrated with the hub (60).

6. The impeller (100) according to claim 5, characterized in that The impeller (100) further comprises an end plate (50) disposed perpendicularly to a rotation axis direction of the impeller (100) and fixedly coupled with or integrated with the hub (60), wherein the blade (10) is fixedly coupled with or integrated with the end plate (50).

7. An air compressor characterized by, The air compressor comprises: a driving device; and The impeller (100) according to claim 5 or 6, wherein the driving device is configured to drive the impeller (100) to rotate.

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