Impellers and centrifugal compressors

Abstract

The present invention relates to an impeller and a centrifugal compressor. The impeller includes a hub and a plurality of blades. The blades are arranged on the outer peripheral surface of the hub. The plurality of blades are spaced and distributed in the circumferential direction of the hub. A compression channel is formed between adjacent blades and the hub. The volume of the compression channel gradually decreases in the direction of airflow. The compression channel includes an intake compression section and an intermediate compression section that are interconnected. The intake compression section is formed by the leading edge of the blade and the hub. The volume change rate of the intake compression section in the direction of airflow is greater than the volume change rate of the intermediate compression section. This makes the volume compression amount of the external fluid small when it just enters the compression channel, avoiding sudden changes. This reduces the flow loss of the fluid when it enters the compression channel, ensures compression energy efficiency, and can control the size of the impeller within a smaller range under the same refrigeration capacity requirements.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal compression equipment, in particular to an impeller and a centrifugal compressor. Background Art

[0002] In the air-conditioning system, refrigerant is mainly used as a medium for heat exchange to achieve the purpose of cooling or heating. The compressor is mainly used to do work on the refrigerant, so that the refrigerant can be continuously circulated and exchanged in the air-conditioning system. With the development of society, people pay more and more attention to environmental issues. In order to reduce the damage of refrigerants to the environment, refrigerants with low GWP values ​​(Global Warming Potential) and ODP values ​​(ozone depression potential) are gradually being developed. However, refrigerants with low GPW values ​​and ODP values ​​have the problem of low refrigeration capacity per unit volume. During the use of this type of refrigerant, in order to achieve the same refrigeration capacity, the compressor impeller generally needs to be designed with a larger size and a higher speed. However, this will result in a larger compressor size and higher manufacturing cost. Based on this, for compressors used for refrigerants with low GPW values ​​and ODP values, it is particularly important to ensure the energy efficiency of the compressor while controlling the size. Summary of the invention

[0003] In view of the problem that a compressor with a smaller impeller size has low energy efficiency when used for a refrigerant with a low unit volumetric refrigeration capacity, the present invention proposes an impeller and a centrifugal compressor, which can achieve the technical effect of effectively controlling the size while ensuring energy efficiency.

[0004] An impeller comprises a hub and a plurality of blades, wherein the blades are arranged on the outer circumferential surface of the hub, the plurality of blades are spaced apart in the circumferential direction of the hub, a compression channel is formed between adjacent blades and the hub, the volume of the compression channel gradually decreases in the direction of airflow, the compression channel comprises an intake compression section and an intermediate compression section which are interconnected, the intake compression section is formed by the leading edge of the blade and the hub, and the volume change rate of the intake compression section in the direction of airflow is greater than the volume change rate of the intermediate compression section.

[0005] The above scheme provides an impeller, and the fluid sucked into the compression channel from outside the impeller can be initially compressed in the suction compression section, and then enter the intermediate compression section for further compression. In the case of the same impeller size, compared with the case where the compression channel is set as a whole section according to the volume change rate of the intermediate compression section, in this case, the volume change rate of the suction compression section is set to a larger form, which can make the volume compression amount of the external fluid when it just enters the compression channel smaller, avoiding sudden changes. Thereby reducing the flow loss of the fluid when entering the compression channel, ensuring the compression energy efficiency, and the impeller size can be controlled within a smaller range under the same refrigeration capacity requirements.

[0006] In one embodiment, the portion on the suction surface of the blade used to enclose the intermediate compression section is the main suction surface, and the portion on the suction surface of the blade used to enclose the suction compression section is a first inclined surface. The first inclined surface is inclined relative to the main suction surface of the blade in a direction close to the pressure surface of the blade, forming a first incision at the leading edge of the blade.

[0007] In one embodiment, the cut depth h1 of the first cut in the thickness direction of the blade is 20%-35% of the thickness H1 of the blade near the leading edge.

[0008] In one embodiment, the cutout length L1 of the first cutout in the airflow direction is 4%-10% of the impeller inlet diameter D1.

[0009] In one embodiment, a first additional cut is provided on the pressure surface of the leading edge of the blade, the cut depth of the first additional cut in the thickness direction of the blade is the first additional depth, the cut depth of the first cut in the thickness direction of the blade is the first depth, and the sum of the first depth and the first additional depth is 20%-35% of the thickness H1 of the blade near the leading edge;

[0010] And / or the length of the first additional cutout in the airflow direction is 4%-10% of the impeller inlet diameter D1.

[0011] In one of the embodiments, the end of the hub close to the leading edge of the blade is an inlet end, and a cutting chamfer is provided at a corner where the outer peripheral surface of the inlet end connects with the end surface.

[0012] In one of the embodiments, the impeller also includes a wheel cover, which is sleeved outside the wheel hub, the blades are located between the wheel cover and the wheel hub, adjacent blades are arranged together with the wheel hub and the wheel cover to form the compression channel, and a cutting chamfer is provided at the corner where the inner circumference of the wheel cover close to the leading edge of the blade is connected to the end face of the wheel cover.

[0013] In one embodiment, a cutting chamfer is provided at the connecting corner between the inner circumference and the end surface of the outlet end of the wheel cover;

[0014] And / or a cutting chamfer is provided at a connecting corner between the outer peripheral surface and the end surface of the hub outlet end.

[0015] In one embodiment, the suction surface of the trailing edge of the blade is provided with a second incision, and a second inclined surface is formed at the trailing edge of the suction surface. The second inclined surface, the relative pressure surface and the outer peripheral surface of the hub form a discharge compression section, and the discharge compression section is connected to the intermediate compression section.

[0016] In one embodiment, the cut depth h2 of the second cut in the thickness direction of the blade is 40%-50% of the thickness H2 of the blade near the trailing edge.

[0017] In one embodiment, the cutout length L2 of the second cutout in the airflow direction is 4%-10% of the impeller outlet diameter D2.

[0018] In one of the embodiments, a second additional cutout is provided on the pressure surface of the trailing edge of the blade.

[0019] A centrifugal compressor comprises the impeller described in any one of the above items.

[0020] The above scheme provides a centrifugal compressor, which can effectively control the size while ensuring energy efficiency by adopting the impeller described in any of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is a front view of the impeller described in this embodiment;

[0024] Figure 2 for Figure 1 A cross-sectional view of the impeller shown;

[0025] Figure 3 A front view of the impeller after the impeller cover is hidden;

[0026] Figure 4 is a schematic diagram of the structure of the blade described in this embodiment;

[0027] Figure 5 This is a schematic diagram of cutting at the trailing edge of the suction surface of the blade according to this embodiment;

[0028] Figure 6 is a cross-sectional view of an impeller in another embodiment;

[0029] Figure 7 for Figure 6 A partial enlarged view of the middle A;

[0030] Figure 8 for Figure 6 A partial enlarged view of point B in the middle.

[0031] Description of reference numerals:

[0032] 10. Impeller; 11. Hub; 12. Wheel cover; 13. Blade; 131. Leading edge; 132. Trailing edge; 133. Suction surface; 1331. First inclined surface; 1332. Main suction surface; 1333. Second inclined surface; 134. Pressure surface; 14. Compression channel; 20. Cutting chamfer. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0034] like Figures 1 to 3 As shown, in one embodiment, an impeller 10 is provided, comprising a hub 11 and a plurality of blades 13, wherein the blades 13 are arranged on the outer peripheral surface of the hub 11, and the plurality of blades 13 are spaced apart and distributed in the circumferential direction of the hub 11. Figure 3 As shown, a compression channel 14 is formed between adjacent blades 13 and the hub 11. The volume of the compression channel 14 gradually decreases in the direction of airflow. During the rotation of the impeller 10, the fluid in the compression channel 14 moves toward the outlet of the impeller 10 under the action of centrifugal force and is discharged from the impeller 10, forming a negative pressure at the inlet of the impeller 10, and the external fluid is sucked into the impeller 10 under the action of the negative pressure.

[0035] Furthermore, if Figure 3 and Figure 4As shown, the compression channel 14 includes an intake compression section and an intermediate compression section that are interconnected. The intake compression section is formed by the leading edge 131 of the blade 13 and the hub 11. The leading edge 131 of the blade 13 refers to the portion of the blade 13 close to the inlet of the impeller 10. The volume change rate of the intake compression section in the direction of airflow is greater than the volume change rate of the intermediate compression section. The volume change rate refers to the volume change of the compression channel 14 when moving a unit distance in the direction of airflow.

[0036] The above scheme provides an impeller 10, in which the fluid sucked into the compression channel 14 from outside the impeller 10 can be initially compressed in the suction compression section, and then enter the intermediate compression section for further compression. In the case of the same size of the impeller 10, compared with the case where the compression channel 14 is set as a whole section according to the volume change rate of the intermediate compression section, the volume change rate of the suction compression section is set to a larger form in this case, which can make the volume compression change of the external fluid when it just enters the compression channel 14 smaller, avoiding the situation of sudden compression. In other words, compared with the impeller in which the suction surface and pressure surface of the traditional blade are designed as smooth curved surfaces, the volume of the suction compression section in this case is larger than the volume of the space enclosed by the leading edge of the blade and the hub and the wheel cover in the traditional impeller, so that the sudden volume change of the fluid when it is sucked into the compression channel 14 can be effectively alleviated. Thereby reducing the flow loss of the fluid when entering the compression channel 14, ensuring the compression energy efficiency, and the size of the impeller 10 can be controlled within a smaller range under the same refrigeration capacity requirements.

[0037] Specifically, the volume of the suction compression section is made larger. Figures 1 to 5 As shown, on the basis of the traditional blade, a cutout can be provided on the suction surface 133 or the pressure surface 134 of the leading edge 131 of the blade 13 to form an inclined surface, so that the leading edge 131 of the blade 13 and the hub 11 and the wheel cover 12 can be surrounded to form the suction compression section with a larger volume. Figure 6 and Figure 7 As shown, a cutting chamfer 20 is provided at a corner where a portion of the outer circumferential surface of the hub 11 close to the leading edge 131 is connected to the end surface.

[0038] For example, in one embodiment, Figure 3 As shown, the portion of the suction surface 133 of the blade 13 used to enclose and form the intermediate compression section is the main suction surface 1332, and the portion of the suction surface 133 of the blade 13 used to enclose and form the suction compression section is the first inclined surface 1331. Figure 3 and Figure 4As shown, the first inclined surface 1331 is inclined relative to the main suction surface 1332 of the blade 13 toward the pressure surface 134 of the blade 13, thereby obtaining the suction-compression section with a larger volume.

[0039] The inclination of the first inclined surface 1331 relative to the main suction surface 1332 is visually reflected as follows: Figure 4 As shown, a first cutout is formed on the suction surface 133 of the leading edge 131 of the blade 13. It can be understood that, compared with a conventional blade, the blade 13 of the impeller 10 in this case is similar to the first cutout formed by cutting on a conventional blade. This increases the flow area of ​​the compression channel 14, reduces the uneven flow velocity at the entrance of the compression channel 14, and reduces the sudden change in volume when the fluid enters the compression channel 14.

[0040] More specifically, considering the strength of the blade 13, in one embodiment, Figure 5 As shown, the cut depth h1 of the first cut in the thickness direction of the blade 13 is 20%-35% of the thickness H1 of the blade 13 near the leading edge 131. Thus, the strength of the blade 13 is not affected while ensuring energy efficiency and controlling the size.

[0041] Similarly, further, in one embodiment, if Figure 2 and Figure 5 As shown, the cut length L1 of the first cutout in the airflow direction is 4%-10% of the inlet diameter D1 of the impeller 10 .

[0042] Further, in another embodiment, the pressure surface 134 of the leading edge 131 of the blade 13 is provided with a first additional cutout, forming a first additional inclined surface at the leading edge 131 of the pressure surface 134. The cutout depth of the first additional cutout in the thickness direction of the blade 13 is the first additional depth.

[0043] The first additional depth may be 20%-35% of the thickness H1 of the blade 13 near the leading edge 131. The length of the first additional cutout in the airflow direction may be 4%-10% of the inlet diameter D1 of the impeller 10.

[0044] In other words, the result of the larger volume of the suction compression section can be obtained by setting the first additional cut. Optionally, the cuts can be set on both the pressure surface 134 and the suction surface 133 of the leading edge 131 of the blade 13, so as to finally obtain a larger volume of the suction compression section. However, considering the problem of the inlet installation angle of the blade 13, in order to avoid the impact loss caused by changing the installation angle, it is preferred to only cut the suction surface 133.

[0045] Furthermore, in one embodiment, a cut is provided on both the pressure surface 134 and the suction surface 133 of the leading edge 131 of the blade 13, the cut depth of the first cut in the thickness direction of the blade 13 is a first depth, and the sum of the first depth and the first additional depth is 20%-35% of the thickness H1 of the portion of the blade 13 close to the leading edge 131. When the pressure surface 134 and the suction surface 133 are cut at the same time, in order to consider the strength of the blade 13, it is preferred that the sum of the first depth and the first additional depth be controlled within the above range.

[0046] Furthermore, similarly, the length of the first additional cutout in the airflow direction is 4%-10% of the inlet diameter D1 of the impeller 10 .

[0047] Further, in another embodiment, if Figure 6 and Figure 7 As shown, the end of the hub 11 close to the leading edge 131 of the blade 13 is the inlet end, and a cutting chamfer 20 is provided at the corner where the outer peripheral surface of the inlet end connects with the end surface. Specifically, the thickness of the cutting chamfer 20 can be 1-3 mm, and the cutting length can be 5-20 mm. Here, the thickness of the cutting chamfer 20 refers to the cutting depth in the radial direction of the inlet end, and the cutting length refers to the length of the cutting chamfer 20 in the axial direction of the inlet end.

[0048] Further, in one embodiment, if Figure 6 As shown, the impeller 10 further includes a wheel cover 12, the wheel cover 12 is sleeved outside the wheel hub 11, the blades 13 are located between the wheel cover 12 and the wheel hub 11, and adjacent blades 13, the wheel hub 11 and the wheel cover 12 are surrounded to form the compression channel 14. Figure 7 As shown, a cutting chamfer 20 is provided at the corner where the inner circumference of the impeller 12 near the leading edge 131 of the blade 13 is connected to the end face of the impeller 12. This further enables the compression amount of the fluid entering the impeller 10 to increase slowly and gradually, rather than being compressed suddenly.

[0049] Furthermore, in one embodiment, the compression channel 14 further includes a discharge compression section. The suction compression section, the intermediate compression section and the discharge compression section are sequentially connected in the airflow direction. The space enclosed by the leading edge 131 of the blade 13 and the hub 11 and the wheel cover 12 is the suction compression section. In other words, Figure 3 and Figure 4 As shown, when the leading edge 131 of the blade 13 is provided with the first inclined surface 1331, as shown in Figure 3As shown, the space enclosed by the first inclined surface 1331 and the blades 13 opposite to it, as well as the hub 11 and the wheel cover 12 is the suction compression section. The discharge compression section is the space enclosed by the trailing edge 132 of the blades 13, the hub 11 and the wheel cover 12. Figure 3 As shown, the suction surface 133 of the trailing edge 132 of the blade 13 is provided with a second cutout, and a second inclined surface 1333 is formed at the trailing edge 132 of the suction surface 133. The space enclosed by the second inclined surface 1333 and the blade 13 opposite to it, as well as the hub 11 and the wheel cover 12 is the discharge compression section. The intermediate compression section is the portion of the compression channel 14 located between the suction compression section and the discharge compression section. Specifically, Figure 3 As shown, the discharge compression section is the space enclosed by the main suction surface 1332 and the corresponding blades 13 as well as the hub 11 and the wheel cover 12.

[0050] Further, in one embodiment, if Figure 6 and Figure 8 As shown, a cutting chamfer 20 is provided at the connecting corner between the inner circumference and the end face of the outlet end of the wheel cover 12. And / or a cutting chamfer 20 is provided at the connecting corner between the outer circumference and the end face of the outlet end of the wheel hub 11.

[0051] As a result, the fluid in the compression channel 14 will undergo preliminary expansion in the discharge compression section before being discharged from the impeller 10, thereby improving the uneven velocity of the fluid at the outlet of the impeller 10, and at the same time, it can also reduce velocity slip and increase the efficiency of the impeller 10.

[0052] Similarly, in another embodiment, if Figures 3 to 5 As shown, the suction surface 133 of the trailing edge 132 of the blade 13 is provided with a second cutout. A second inclined surface 1333 is formed on the trailing edge 132 of the suction surface 133. Figure 3 As shown, the second inclined surface 1333 , the opposite pressure surface 134 and the outer peripheral surface of the hub 11 together form a discharge compression section, so that the fluid can undergo preliminary expansion in the discharge compression section.

[0053] Specifically, in one embodiment, considering the strength of the blade 13, as shown in FIG. Figure 5 As shown, the cutting depth h2 of the second cutting in the thickness direction of the blade 13 is 40%-50% of the thickness H2 of the portion of the blade 13 close to the trailing edge 132 .

[0054] Preferably, a cutting depth h2 of the second cutting in the thickness direction of the blade 13 is 50% of a thickness H2 of a portion of the blade 13 close to the trailing edge 132 .

[0055] The thickness H1 of the portion close to the leading edge 131 of the blade 13 described herein refers to the thickness of the portion close to the leading edge 131 of the blade 13 without cutting. Similarly, the thickness H2 of the portion close to the trailing edge 132 of the blade 13 described herein refers to the thickness of the portion close to the trailing edge 132 of the blade 13 without cutting.

[0056] Similarly, in one embodiment, if Figure 5 As shown, the length L2 of the second cutout in the airflow direction is 4%-10% of the outlet diameter D2 of the impeller 10 , which not only provides a sufficient diffusion length for the fluid, but also takes into account the strength of the blade 13 .

[0057] Furthermore, in one embodiment, the pressure surface 134 of the trailing edge 132 of the blade 13 is provided with a second additional cutout.

[0058] The second additional cutout is provided to form a second additional inclined surface at the trailing edge 132 of the pressure surface 134, the cutout depth of the second additional cutout in the thickness direction of the blade 13 is the second additional depth, the cutout depth of the second cutout in the thickness direction of the blade 13 is the second depth, and the sum of the second depth and the second additional depth is 40%-50% of the thickness H2 of the portion of the blade 13 close to the trailing edge 132;

[0059] And / or the length of the second additional cutout in the airflow direction is 4%-10% of the outlet diameter D2 of the impeller 10 .

[0060] Furthermore, in yet another embodiment, a centrifugal compressor is provided, comprising the impeller 10 described in any one of the above items.

[0061] The above scheme provides a centrifugal compressor, which can effectively control the size while ensuring energy efficiency by adopting the impeller 10 described in any of the above embodiments. Under the condition of the same refrigeration capacity, the size of the centrifugal compressor adopting the impeller 10 described in the present application is smaller.

[0062] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0064] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0066] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An impeller, characterized in that: The impeller comprises a hub and a plurality of blades, wherein the blades are arranged on the outer peripheral surface of the hub, the plurality of blades are spaced apart in the circumferential direction of the hub, a compression channel is formed between adjacent blades and the hub, the volume of the compression channel gradually decreases in the direction of airflow, the compression channel comprises an intake compression section and an intermediate compression section which are interconnected, the leading edge of the blade is provided with a first inclined surface, the impeller further comprises a wheel cover, the space enclosed by the first inclined surface and the blades opposite to the hub and the wheel cover is the intake compression section, and the volume change rate of the intake compression section in the direction of airflow is greater than the volume change rate of the intermediate compression section.

2. The impeller according to claim 1, characterized in that: The portion on the suction surface of the blade used to enclose the middle compression section is the main suction surface, and the portion on the suction surface of the blade used to enclose the suction compression section is the first inclined surface. The first inclined surface is inclined relative to the main suction surface of the blade in a direction close to the pressure surface of the blade, forming a first incision at the leading edge of the blade.

3. The impeller according to claim 2, characterized in that: The cutting depth h1 of the first cutting in the thickness direction of the blade is 20%-35% of the thickness H1 of the blade near the leading edge; the thickness H1 of the blade near the leading edge refers to the thickness of the blade leading edge without cutting.

4. The impeller according to claim 2, characterized in that: The cutout length L1 of the first cutout in the airflow direction is 4%-10% of the impeller inlet diameter D1.

5. The impeller according to claim 2, characterized in that: The pressure surface of the leading edge of the blade is provided with a first additional cut, the cut depth of the first additional cut in the direction of the thickness of the blade is the first additional depth, the cut depth of the first cut in the direction of the thickness of the blade is the first depth, and the sum of the first depth and the first additional depth is 20%-35% of the thickness H1 of the blade near the leading edge; the thickness H1 of the blade near the leading edge refers to the thickness of the leading edge of the blade without cutting; And / or the length of the first additional cutout in the airflow direction is 4%-10% of the impeller inlet diameter D1.

6. The impeller according to claim 1, characterized in that One end of the hub close to the leading edge of the blade is an inlet end, and a cutting chamfer is provided at a corner where the outer peripheral surface of the inlet end is connected to the end surface of the hub.

7. The impeller according to any one of claims 1 to 6, characterized in that: The wheel cover is sleeved outside the wheel hub, the blades are located between the wheel cover and the wheel hub, adjacent blades, the wheel hub and the wheel cover are arranged to form the compression channel, and a cutting chamfer is provided at the corner where the inner circumference of the wheel cover close to the leading edge of the blade is connected to the end face of the wheel cover.

8. The impeller according to claim 7, characterized in that A cutting chamfer is provided at the connecting corner between the inner circumference of the wheel cover outlet end and the end surface of the wheel cover; And / or a cutting chamfer is provided at a connecting corner between the outer peripheral surface of the hub outlet end and the hub end surface.

9. The impeller according to any one of claims 1 to 6, characterized in that: The suction surface of the trailing edge of the blade is provided with a second cutout, and a second inclined surface is formed at the trailing edge of the suction surface. The second inclined surface, the relative pressure surface and the outer peripheral surface of the hub form a discharge compression section, and the discharge compression section is connected to the intermediate compression section.

10. The impeller according to claim 9, characterized in that The depth h2 of the second cut in the thickness direction of the blade is 40%-50% of the thickness H2 of the blade near the trailing edge; the thickness H2 of the blade near the trailing edge refers to the thickness of the blade trailing edge without cutting.

11. The impeller according to claim 9, characterized in that The cutout length L2 of the second cutout in the airflow direction is 4%-10% of the impeller outlet diameter D2.

12. The impeller according to any one of claims 1 to 6, characterized in that: The pressure surface of the trailing edge of the blade is provided with a second additional cutout.

13. A centrifugal compressor, characterized in that: The impeller comprises the impeller according to any one of claims 1 to 12.

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