Centrifugal impeller, centrifugal compressor, air conditioner outdoor unit and air conditioner

Abstract

The disclosure provides a centrifugal impeller, a centrifugal compressor, an air conditioner outdoor unit and an air conditioner. The centrifugal impeller comprises a hub and a plurality of blades mounted on the hub, the blade comprising a pressure surface, a suction surface, a leading edge located at the intersection of the pressure surface and the suction surface at the inlet of the centrifugal impeller, and a trailing edge located at the intersection of the pressure surface and the suction surface at the outlet of the centrifugal impeller, the leading edge gradually tilting to the opposite direction of the airflow direction from the radial inner side to the radial outer side of the centrifugal impeller and gradually increasing the included angle with the axial direction of the centrifugal impeller. The centrifugal impeller, the centrifugal compressor, the air conditioner outdoor unit and the air conditioner provided by the disclosure are beneficial to reducing the aerodynamic loss of the centrifugal impeller caused by the non-uniform axial velocity of the airflow at the inlet of the centrifugal impeller, thereby improving the efficiency of the centrifugal impeller.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of pumping devices, in particular to a centrifugal impeller, a centrifugal compressor, an outdoor unit of an air conditioner and an air conditioner. BACKGROUND

[0002] The centrifugal impeller comprises a hub and a plurality of blades mounted on the hub. The blades comprise a pressure surface, a suction surface, a leading edge located at the intersection of the pressure surface and the suction surface at the inlet of the centrifugal impeller, and a trailing edge located at the intersection of the pressure surface and the suction surface at the outlet of the centrifugal impeller.

[0003] Figure 1 A schematic view of the structure of the blades of the related art centrifugal impeller is shown. Referring to Figure 1 The leading edge 13' of the blade 1' is gradually inclined to the opposite direction of the airflow direction in from the radially inner side to the radially outer side of the centrifugal impeller and forms an angle λ with the axial direction of the centrifugal impeller.

[0004] In Figure 1 the design of the centrifugal impeller shown, it is generally approximately considered that the airflow direction in at the inlet of the centrifugal impeller is parallel to the axial direction of the centrifugal impeller (i.e. the horizontal direction shown in Figure 1 , the size of the inlet of the centrifugal impeller is generally designed according to the volumetric flow rate of the airflow at the inlet of the centrifugal impeller and the axial average velocity v of the inlet airflow. Figure 2 In Figure 2 1A is a blade model when designing the blades of the centrifugal impeller. According to Figure 2 the distribution principle of the axial average velocity v of the airflow at the inlet of the centrifugal impeller shown in Figure 1 , the flow passage area is small near the hub and large near the shroud of the centrifugal impeller. As Figure 1 shown, the leading edge 13' of the blade 1' forms an angle λ with the axial direction of the centrifugal impeller, which can increase the area of the hub of the centrifugal impeller and thus prevent the centrifugal impeller from being blocked.

[0005] In addition, as Figure 3 shown, the trailing edge 14' of the blade 1' of the related art centrifugal impeller forms a substantially right angle with the pressure surface 11' and the suction surface 12'.

[0006] In the implementation of the technical solution of the present disclosure, the inventors have found that:

[0007] The shape of the leading edge 13' of the blade 1' of the above centrifugal impeller, although it can ensure that the centrifugal impeller basically meets the flow requirement, the impact loss and separation loss generated by the inlet airflow of the centrifugal impeller are large, which adversely affects the efficiency of the centrifugal impeller.

[0008] The shape of the trailing edge 14' of the blade 1' of the above centrifugal impeller is such that a larger backward slip angle is generated after the gas flow flows out of the impeller, and the gas flow slip increases the friction loss and separation loss of the gas flow in the subsequent flow passage, which adversely affects the efficiency of the centrifugal impeller. SUMMARY

[0009] The purpose of the present disclosure is to provide a centrifugal impeller, a centrifugal compressor, an air conditioner outdoor unit and an air conditioner, aiming to improve the efficiency of the centrifugal impeller.

[0010] The first aspect of the present disclosure provides a centrifugal impeller, comprising a hub and a plurality of blades mounted on the hub, the blades comprising a pressure surface, a suction surface, a leading edge located at the intersection of the pressure surface and the suction surface at the inlet of the centrifugal impeller, and a trailing edge located at the intersection of the pressure surface and the suction surface at the outlet of the centrifugal impeller, the leading edge gradually tilting to the opposite direction of the gas flow direction and gradually increasing the angle with the axial direction of the centrifugal impeller from the radially inner side to the radially outer side of the centrifugal impeller.

[0011] In some embodiments of the centrifugal impeller, the angle of the leading edge with the axial direction of the centrifugal impeller gradually increases or continuously increases.

[0012] In some embodiments of the centrifugal impeller, the leading edge comprises a plurality of straight line segments connected in sequence, a plurality of curved line segments connected in sequence, a single curved line segment, or a combination of at least one straight line segment and at least one curved line segment.

[0013] In some embodiments of the centrifugal impeller, the maximum radius m and the minimum radius n of the inlet of the centrifugal impeller are determined according to the following formula:

[0014] ;

[0015] wherein Mv is the design value of the volume flow rate per unit time of the gas flow at the inlet of the centrifugal impeller, ax2+bx+c is the axial velocity of the gas flow at the inlet of the centrifugal impeller at a radius x centered on the axis of the centrifugal impeller, and a, b, c are constants determined according to simulation or experiment.

[0016] In some embodiments of the centrifugal impeller, one end of the pressure surface close to the trailing edge comprises a first curved surface portion connected to the trailing edge, and one end of the suction surface close to the trailing edge comprises a second curved surface portion connected to the trailing edge, the radius of curvature of the first curved surface portion being greater than the radius of curvature of the second curved surface portion.

[0017] In some embodiments of the centrifugal impeller, the first curved surface portion is a first circular arc surface, and the second curved surface portion is a second circular arc surface.

[0018] In some embodiments of the centrifugal impeller, the ratio of the radius of the first circular arc surface to the radius of the second circular arc surface is about 2:1.

[0019] The second aspect of the present disclosure provides a centrifugal compressor comprising the centrifugal impeller of the first aspect of the present disclosure.

[0020] The third aspect of the present disclosure provides an air conditioner outdoor unit comprising the centrifugal compressor of the second aspect of the present disclosure.

[0021] The fourth aspect of the present disclosure provides an air conditioner comprising the air conditioner outdoor unit of the third aspect of the present disclosure.

[0022] Based on the centrifugal impeller provided by the present disclosure, the leading edge of the blade gradually inclines to the opposite direction of the airflow direction and gradually increases the included angle with the axial direction of the centrifugal impeller from the radial inner side to the radial outer side of the centrifugal impeller, which is conducive to reducing the aerodynamic loss of the centrifugal impeller caused by the non-uniform axial velocity of the airflow at the inlet of the centrifugal impeller, such as the impact loss of the airflow on the pressure surface of the blade and the separation loss at the blade tip, thereby improving the efficiency of the centrifugal impeller.

[0023] The centrifugal compressor, the air conditioner outdoor unit and the air conditioner provided by the present disclosure have the same advantages as the centrifugal impeller provided by the present disclosure.

[0024] Other features of the present disclosure and its advantages will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are included to provide a further understanding of the present disclosure and constitute a part of this application, illustrate certain illustrative embodiments of the present disclosure and are used to explain the present disclosure, but do not limit the present disclosure. In the drawings:

[0026] Figure 1 A structure diagram of a blade of a centrifugal impeller of the related art.

[0027] Figure 2 A schematic diagram of an inlet airflow velocity distribution used in determining the shape of the leading edge of the blade of the centrifugal impeller of the prior art.

[0028] Figure 3 A schematic diagram of the local structure at the trailing edge of the blade of the centrifugal impeller of the prior art.

[0029] Figure 4 A front view structure schematic diagram of the centrifugal impeller of an embodiment of the present disclosure.

[0030] Figure 5 A front view structure schematic diagram of the centrifugal impeller of an embodiment of the present disclosure. Figure 4 A side view structure schematic diagram of the centrifugal impeller shown.

[0031] Figure 6 A structural schematic view of a blade of a centrifugal impeller. Figure 4 A structural schematic view of a blade of a centrifugal impeller.

[0032] Figure 7 A structural schematic view of a blade of a centrifugal impeller. Figure 4 A structural schematic view of a blade of a centrifugal impeller.

[0033] Figure 8 A structural schematic view of a blade of a centrifugal impeller. Figure 4 A structural schematic view of a blade of a centrifugal impeller. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present disclosure.

[0035] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the present disclosure. Meanwhile, it should be understood that the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship for the convenience of description. The technology, methods, and devices known to those of ordinary skill in the related art can not be discussed in detail, but should be considered as part of the authorized description under appropriate circumstances. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0036] In the description of the present disclosure, it should be understood that the use of the words "first", "second", and the like to qualify parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present disclosure.

[0037] In the description of the present disclosure, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present disclosure and simplifying the description, without the opposite indication, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore cannot be understood as a limitation on the protection scope of the present disclosure; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0038] To solve the technical problem of large impact loss and separation loss of airflow at the inlet in the related art centrifugal impeller, the present application provides a centrifugal impeller. As shown in Figure 4 and Figure 5 , the centrifugal impeller comprises a hub 2 and a plurality of blades 1 mounted on the hub 2, the blade 1 comprises a pressure surface 11, a suction surface 12, a leading edge 13 located at the intersection of the pressure surface 11 and the suction surface 12 at the inlet of the centrifugal impeller, and a trailing edge 14 located at the intersection of the pressure surface 11 and the suction surface 12 at the outlet of the centrifugal impeller. As shown in Figure 6 , the leading edge 13 gradually tilts to the opposite direction of the airflow direction from the radially inner side to the radially outer side of the centrifugal impeller and gradually increases the included angle with the axial direction of the centrifugal impeller. Figure 4 The arrow direction in the figure represents the rotation direction of the centrifugal impeller when working. Figure 6 The figure shows the included angle of the leading edge of the part of the leading edge 13 closest to the hub 2 with the axial direction of the centrifugal impeller. Figure 6 The airflow direction in the figure is parallel to the axial direction of the centrifugal impeller.

[0039] The axial velocity v x of the airflow at the inlet of the centrifugal impeller is fitted by a quadratic curve v 2 =ax x +bx+c The distribution of the centrifugal impeller in the radial direction is more in line with the real situation, where v x is the axial velocity of the airflow at the inlet of the centrifugal impeller at a radius x centered on the axis of the centrifugal impeller, and a, b, c are constants determined according to simulation or experiment.

[0040] As shown in Figure 7 , as the radius x increases, the axial velocity of the airflow at the inlet of the centrifugal impeller increases, and the increasing amplitude becomes larger and larger. Figure 7 In the figure, 1B is a blade model when designing the blade of the centrifugal impeller. As shown in Figure 6As shown, the front edge 13 of the blade 1 of the centrifugal impeller of the embodiment of the present disclosure gradually increases the angle between the airflow direction in and the axial direction of the centrifugal impeller from the radially inner side to the radially outer side of the centrifugal impeller, that is, the structure of gradually changing the front edge angle of the blade of the centrifugal impeller, which is more in line with the radial distribution rule of the quadratic curve of the axial velocity of the airflow at the inlet of the centrifugal impeller. From the hub 2 to the shroud (not shown, the shroud is connected to the radially outer side of each centrifugal blade 1), the flow area rapidly increases with the increase of the radius, and at the same time, the blockage effect caused by the blade 1 gradually decreases due to the gradual increase of the axial velocity of the airflow. The angle of the front edge angle gradually increases from the hub 2 to the shroud, which is beneficial to the gradual slowing down of the axial velocity of the airflow, so that the structure of gradually changing the front edge angle of the blade of the centrifugal impeller is beneficial to reducing the aerodynamic loss of the centrifugal impeller at the inlet caused by the non-uniform axial velocity of the airflow, such as the impact loss of the airflow on the pressure surface 11 of the blade 1 and the separation loss at the blade tip, thereby improving the efficiency of the centrifugal impeller.

[0041] In some embodiments of the centrifugal impeller, the angle between the front edge 13 and the axial direction of the centrifugal impeller can gradually increase or continuously increase. For example, in some embodiments of the centrifugal impeller, the front edge 13 can include a plurality of straight line segments connected in sequence, a plurality of curved line segments connected in sequence, a single curved line segment, or a combination of at least one straight line segment and at least one curved line segment.

[0042] In some embodiments of the centrifugal impeller, the maximum radius m and the minimum radius n of the inlet of the centrifugal impeller are determined according to the following formula:

[0043] ;

[0044] wherein Mv is the design value of the volume flow rate of the airflow at the inlet of the centrifugal impeller per unit time, ax 2 +bx+c is the axial velocity of the airflow at the inlet of the centrifugal impeller at a radius x centered on the axis of the centrifugal impeller, and a, b, and c are constants determined according to simulation or experiment.

[0045] Based on the quadratic curve v x =ax 2 +bx+c, the maximum radius m and the minimum radius n of the inlet of the centrifugal impeller are reasonably set, so that the size of the inlet of the centrifugal impeller is better adapted to the structure of gradually changing the front edge angle of the blade of the centrifugal impeller, which is beneficial to the structure of gradually changing the front edge angle of the blade of the centrifugal impeller to realize its function, thereby improving the efficiency of the centrifugal impeller.

[0046] For example, Figure 8As shown, in the centrifugal impeller of some embodiments, an end of the pressure surface 11 close to the trailing edge 14 comprises a first curved portion 111 connected with the trailing edge 14, and an end of the suction surface 12 close to the trailing edge 14 comprises a second curved portion 121 connected with the trailing edge 14, and the first curved portion 111 has a radius of curvature greater than that of the second curved portion 121.

[0047] The above arrangement at the trailing edge 14 of the blade 1 of the centrifugal impeller takes into account the influence of the pressure gradient of the airflow on the pressure difference existing between the pressure surface 11 and the suction surface 12, and the gradual thinning of the blade 1 at the centrifugal outlet, which can effectively reduce the energy loss at the outlet of the centrifugal impeller due to airflow slip, thereby facilitating the improvement of the efficiency of the centrifugal impeller.

[0048] In the centrifugal impeller of some embodiments, the first curved portion 111 is a first circular arc surface, and the second curved portion 121 is a second circular arc surface.

[0049] The adoption of the double-circular-arc-section trailing edge at the outlet of the centrifugal impeller facilitates the reduction of the loss due to airflow slip, effectively reduces the outlet loss of the centrifugal impeller, and improves the working efficiency of the centrifugal impeller.

[0050] The curvature design at the trailing edge 14 of the blade 1 is performed in combination with the pressure difference between the pressure surface 11 and the suction surface 12 and the thickness of the blade 1. For example, in the centrifugal impeller of some embodiments, the ratio of the radius of the first circular arc surface to the radius of the second circular arc surface is about 2:1.

[0051] The disclosure also provides a centrifugal compressor. The centrifugal compressor comprises the centrifugal impeller of the disclosure.

[0052] The centrifugal compressor of the disclosure has the advantages of the centrifugal impeller of the disclosure.

[0053] The disclosure also provides an air conditioner outdoor unit comprising the centrifugal compressor of the disclosure. The disclosure also provides an air conditioner comprising the air conditioner outdoor unit of the disclosure. The air conditioner outdoor unit and the air conditioner of the disclosure have the advantages of the centrifugal impeller of the disclosure.

[0054] The centrifugal impeller, the centrifugal compressor, the air conditioner outdoor unit, and the air conditioner of the disclosure can be used in various application sites of the centrifugal impeller, the centrifugal compressor, the air conditioner outdoor unit, and the air conditioner. In addition, they are also suitable for sites requiring high pressure ratio while still ensuring high efficiency. For example, low-GWP refrigerant media have the characteristics of low density and high compression difficulty, and the adoption of the centrifugal impeller or the centrifugal compressor of the disclosure for the compression of low-GWP refrigerant media can achieve high working efficiency at high pressure ratio.

[0055] According to the above description, in the centrifugal impeller, the centrifugal compressor, the air conditioner outdoor unit and the air conditioner, an effective measure for improving the efficiency of the centrifugal impeller is provided. For the impact loss and the separation loss generated at the inlet of the centrifugal impeller, the leading edge angle of the blade 1 of the centrifugal impeller and the diameter and of the inlet are optimized according to the rule that the axial velocity of the airflow at the inlet of the centrifugal impeller is distributed along the radial direction of the centrifugal impeller according to a quadratic function, which is beneficial to improve the efficiency of the centrifugal impeller. For the airflow slip loss at the outlet of the centrifugal impeller caused by the thickness of the blade 1 at the trailing edge 14, the structure at the trailing edge 14 of the blade 1 is optimized according to the pressure difference force generated by the pressure surface 11 and the suction surface 12, which can effectively reduce the loss at the outlet of the centrifugal impeller and improve the efficiency of the centrifugal impeller.

[0056] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present disclosure rather than limit them; although the present disclosure has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the specific embodiments of the present disclosure can be modified or some technical features can be replaced by equivalent ones, which should be covered in the technical solution range of the present disclosure.

Claims

1. A centrifugal impeller comprising a hub (2) and a plurality of blades (1) mounted on said hub (2), said blades (1) comprising a pressure face (11), a suction face (12), a leading edge (13) at the intersection of said pressure face (11) and said suction face (12) at the inlet of said centrifugal impeller and a trailing edge (14) at the intersection of said pressure face (11) and said suction face (12) at the outlet of said centrifugal impeller, characterized in that, The leading edge (13) is gradually inclined to the opposite direction of the airflow direction (in) and gradually increases the angle with the axial direction of the centrifugal impeller from the radial inner side to the radial outer side of the centrifugal impeller.

2. The centrifugal impeller of claim 1, wherein The angle of the leading edge (13) with the axial direction of the centrifugal impeller gradually or continuously increases.

3. The centrifugal impeller of claim 1, wherein The leading edge (13) comprises a plurality of straight line segments connected in sequence, a plurality of curve segments connected in sequence, a single curve segment, or a combination of at least one straight line segment and at least one curve segment.

4. The centrifugal impeller according to any one of claims 1 to 3, characterized in that The maximum radius m and the minimum radius n of the inlet of the centrifugal impeller are determined according to the following formula: ； wherein Mv is a design value of the volume flow rate of the gas stream at the inlet of the centrifugal impeller per unit of time, ax 2 + bx + c is the axial velocity of the gas stream at the inlet of the centrifugal impeller at the radius x from the axis of the centrifugal impeller, a, b, c being constants determined on the basis of simulations or experiments.

5. The centrifugal impeller according to any one of claims 1 to 3, characterized in that One end of the pressure surface (11) close to the trailing edge (14) comprises a first curved surface part (111) connected with the trailing edge (14), and one end of the suction surface (12) close to the trailing edge (14) comprises a second curved surface part (121) connected with the trailing edge (14), the curvature radius of the first curved surface part (111) is greater than the curvature radius of the second curved surface part (121).

6. The centrifugal impeller of claim 5, wherein The first curved surface part (111) is a first circular arc surface, and the second curved surface part (121) is a second circular arc surface.

7. The centrifugal impeller of claim 6, wherein The ratio of the radius of the first circular arc surface to the radius of the second circular arc surface is 2:

1.

8. A centrifugal compressor characterized by, The centrifugal compressor comprises the centrifugal impeller according to any one of claims 1 to 7.

9. An air conditioner outdoor unit characterized by comprising: The air conditioner outdoor unit comprises the centrifugal compressor according to claim 8.

10. An air conditioner characterized by comprising: The air conditioner outdoor unit comprises the centrifugal compressor according to claim 9.

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