Centrifugal fan and air conditioner

Abstract

The utility model discloses a centrifugal fan and an air conditioner. The centrifugal fan comprises a volute, a volute tongue and an impeller. A containing cavity is formed in the volute, and the air outlet communicates with the outer side of the containing cavity. The volute tongue is arranged at the air outlet; the impeller is rotatably arranged in the containing cavity and comprises a hub, a wheel cover and a plurality of blades, the blades are arc-shaped blades and connected between the hub and the wheel cover, the blades are distributed at intervals in the circumferential direction of the impeller and define a center cavity, an airflow channel is formed between every two adjacent blades, and the center cavity communicates with the outer side of the impeller through the airflow channels; a spoiler is arranged at the end, close to the interior of the center cavity, of each blade, and part of airflow in the center cavity enters the airflow channel after being spoiled and dispersed through the spoilers. According to the centrifugal fan provided by the embodiment of the utility model, the spoiler disperses the airflow and enables the airflow to act on the initial separation point at the front edge of the blade, so that the turbulence intensity and momentum mixing of a boundary layer near a separation area are enhanced to inhibit flow separation, the efficiency of the fan is improved, and the aerodynamic noise is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to air conditioning technical field especially is involved in a centrifugal fan and air conditioner. BACKGROUND

[0002] Among many fan types, centrifugal fan is widely used in industrial refrigeration-ventilation system, air conditioning equipment and household equipment due to its compact structure, large flow coefficient, high pressure coefficient and low noise. Among them, the aerodynamic performance of multi-blade centrifugal fan is of great significance to energy saving and emission reduction.

[0003] However, due to the short blade of multi-blade centrifugal fan, the suction surface side is prone to low-speed backflow area under large adverse pressure gradient and flow separation of airflow, and the large adverse pressure gradient, that is, the pressure of airflow from the air inlet to the air outlet of the airflow passage is large, and the airflow is not easy to flow through, especially in the volute tongue area close to the air outlet, the volute tongue has a great influence on the pressure fluctuation of the airflow, which makes the airflow separation of the suction surface more obvious, and the efficiency of the fan is deteriorated and aerodynamic noise is generated. SUMMARY

[0004] The utility model discloses at least solve one of the prior art technical problems. Therefore, one purpose of the utility model is to provide a centrifugal fan, which is provided with a spoiler at one end of the blade close to the air inlet of the airflow passage, the spoiler disperses the airflow and makes the airflow act on the initial separation point of the blade leading edge, so as to suppress flow separation by enhancing the turbulence intensity and momentum mixing of the boundary layer near the separation area, thereby improving the efficiency of the fan and reducing aerodynamic noise.

[0005] The centrifugal fan according to the utility model embodiment comprises a volute, a volute tongue and an impeller. The volute is provided with an accommodating cavity, an air outlet and a volute tongue. The air outlet is connected to the outside of the accommodating cavity. The volute tongue is arranged at the air outlet. The impeller is rotatably installed in the accommodating cavity. The impeller comprises a hub, a cover and a plurality of blades. The blades are arc-shaped blades. The hub and the cover are arranged in the axial direction of the impeller. The blades are connected between the hub and the cover. The plurality of blades are arranged in the circumferential direction of the impeller. The plurality of blades enclose a central cavity. The airflow passages are formed between adjacent blades and are used to connect the central cavity and the outside of the impeller. Each blade is provided with a spoiler at one end close to the central cavity. Part of the airflow in the central cavity is adapted to enter the airflow passage after being disturbed and dispersed by the spoiler.

[0006] According to the centrifugal fan, each blade is constructed as an arc-shaped blade, the smoothness of airflow flow is improved, the concave surface of the arc-shaped blade is a pressure surface, and the convex surface is a suction surface, when the impeller rotates, airflow flows from the central cavity of the impeller into the airflow channel formed by adjacent blades, and because the airflow is affected by the adverse pressure gradient when the airflow flows to the volute tongue close to the air outlet, the airflow will produce backflow and separation between the suction surface of the blade at the corresponding position, so that noise is generated and the efficiency of the fan is reduced.

[0007] The side of each blade close to the central cavity is provided with a spoiler, after the airflow passes through the spoiler, the airflow flows to the suction surface through the wake of the spoiler, at this time, the airflow acts on the leading edge of the suction surface of the blade, the leading edge refers to one end of the blade close to the central cavity, so that the turbulence intensity and momentum mixing of the boundary layer near the separation zone of the airflow and the suction surface are enhanced to suppress flow separation, so that the efficiency of the centrifugal fan is improved and the aerodynamic noise is reduced.

[0008] According to the centrifugal fan, the wheel cover comprises an inner fixing ring and an outer fixing ring, the outer fixing ring is located at the outer periphery of the inner fixing ring, one side of the blade close to the central cavity is connected to the inner fixing ring, and the other side away from the central cavity is connected to the outer fixing ring, and the spoiler is connected between the inner fixing ring and the hub.

[0009] Therefore, by arranging the inner fixing ring and the outer fixing ring, both sides of the blade can be fixed, and when the blade is connected to the inner fixing ring, the connection position of the spoiler can be determined through the inner fixing ring, the spoiler is convenient to connect, the positional relationship between the blade and the spoiler can be easily observed, the positional relationship between the multiple spoilers and the corresponding multiple blades can be the same, so that the airflow flowing to each group of airflow channels has the same degree of turbulence of the spoiler, the degree of confusion of the airflow is reduced, and the turbulence intensity and momentum mixing of the edge of the corresponding blade of each spoiler are increased to suppress flow separation.

[0010] According to the centrifugal fan, the two side surfaces of the inner fixing ring in the radial direction are respectively constructed as an inner wall surface and an outer wall surface, the blade is connected between the outer wall surface and the outer fixing ring, and the spoiler is connected to one surface of the inner wall surface or the inner fixing ring facing the hub.

[0011] That is, by setting the inner fixed ring, and connecting the vane and the spoiler on both sides of the inner fixed ring in the radial direction, the vane and the spoiler are spaced apart and the spoiler is fixed on the side of the vane close to the central cavity, and the spoiler can be fixed on the inner wall of the inner fixed ring or the side of the inner fixed ring facing the hub according to the actual situation, when the airflow flows into the airflow passage, the airflow can flow around the spoiler, and in the process of flowing, the airflow can continue to flow to the edge of the suction surface along the space between the spoiler and the vane, thereby reducing the separation of the gas and the edge of the suction surface.

[0012] According to the centrifugal fan, the distance between the spoiler and the vane is L, and 2mm≤L≤3mm is met.

[0013] That is, the distance between the spoiler and the vane should not be too far, if the distance is too far, the airflow continues to disperse after passing through the spoiler, so that it cannot smoothly contact the front end edge of the vane, and the airflow may enter the airflow passage while keeping a distance from the suction surface, the front end edge of the vane is the edge of the vane close to the central cavity, and the airflow backflow is caused by the design of the arc and the influence of the adverse pressure gradient of the airflow at the front end edge of the vane close to the central cavity, which is easy to separate between the front end edge of the vane; that is, by limiting the position of the spoiler, the spoiler can disturb the airflow, and the disturbed airflow can smoothly reach the front end edge of the vane at a closer distance, thereby reducing the noise caused by the separation of the airflow at the front end edge of the vane.

[0014] According to the centrifugal fan, the spoiler is configured as a cylinder, the radius of the cylinder is r, the thickness of the vane along the circumference of the impeller is d, and 30%d≤r≤50%d is met.

[0015] Specifically, by designing the spoiler as a cylinder, the flow resistance of the airflow is reduced, and the airflow can more evenly and smoothly reach the edge of the suction surface after passing through one side of the cylindrical spoiler, and the radius of the spoiler should not be too large, if the radius of the spoiler is too large, the airflow passing through one side of the spoiler cannot contact the end edge of the vane and enter the airflow passage, so that the airflow intensity at the front edge of the vane cannot be enhanced, and the effect of inhibiting the separation of the airflow and the end edge of the suction surface is poor; by limiting the radius range of the cylindrical spoiler, it can be ensured that the airflow passing through one side of the spoiler at least contacts the front edge of the arc-shaped vane, that is, the disturbed airflow can enhance the turbulence intensity and momentum mixing of the boundary layer near the separation zone, thereby better inhibiting the separation between the airflow and the suction surface.

[0016] According to the centrifugal fan, each turbulence member is located at a central position along a circumferential direction of the corresponding blade.

[0017] That is, the turbulence member is located at a central position along a circumferential direction of the corresponding blade, and after the airflow passes through a side edge of one side of the turbulence member, the airflow can flow to an edge of a suction surface of the blade and flow into an airflow channel from the edge of the suction surface, and the airflow also enters an adjacent airflow channel through a side edge of the other side of the turbulence member, so that the airflow is more uniform after passing through the turbulence member, that is, while the airflow separation from the leading edge of the blade is inhibited, the uniformity of the airflow flow is also improved.

[0018] According to the centrifugal fan, one end of the blade close to the central cavity is configured as an arc-shaped structure.

[0019] Then, after the airflow is disturbed by the turbulence member, the airflow flows along the leading edge of the blade of the arc-shaped structure, the smoothness of the flow is improved, the influence of the airflow resistance is reduced, and the airflow can flow along the surface of the arc-shaped structure to the airflow channel after passing through the turbulence member, and the separation between the airflow and the suction surface during the airflow flow is reduced.

[0020] According to the centrifugal fan, the length of the blade and the length of the turbulence member along the axial direction of the impeller are the same.

[0021] In practice, the turbulence member extends along the axial direction of the impeller, and the blade also extends along the axial direction, and when the gas enters the airflow channel formed between adjacent blades, the turbulence member can disturb the airflow on the side close to the central cavity of the blade along the axial direction of the impeller, so that the edge of the suction surface of the blade is enhanced by the airflow along the axial direction of the impeller, thereby reducing the separation between the suction surface of the entire blade and the airflow, and further reducing the noise.

[0022] According to the centrifugal fan, the thickness of the wheel cover along the axial direction is greater than the thickness of the hub along the axial direction.

[0023] Firstly, the hub can serve as a support surface for the plurality of blades, and the area of the hub is large enough to connect the plurality of blades and improve the stability and strength of the connection of the plurality of blades, and the thickness of the wheel cover along the axial direction is large enough to improve the strength of the wheel cover, facilitate the connection of the wheel cover with the blades and the turbulence members, and ensure the stability of the turbulence members and the blades.

[0024] The utility model embodiment further discloses an air conditioner comprising the centrifugal fan.

[0025] The air conditioner has the same advantages as the centrifugal fan and the prior art, and details are not repeated here.

[0026] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1 This is a schematic diagram of the impeller structure of a centrifugal fan according to an embodiment of the present invention;

[0029] Figure 2 This is a side view of the impeller of the centrifugal fan according to an embodiment of the present utility model;

[0030] Figure 3 This is a partial sectional view of the impeller of the centrifugal fan according to an embodiment of the present utility model;

[0031] Figure 4 This is an embodiment of the present utility model. Figure 3 An enlarged schematic diagram of point A.

[0032] Figure label:

[0033] Impeller 1, blades 2, suction surface 21, pressure surface 22, arc-shaped structure 23, hub 3, wheel cover 4, outer fixing ring 41, inner fixing ring 42, outer wall surface 421, inner wall surface 422, turbulence component 5, airflow channel 6. Detailed Implementation

[0034] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0035] The following is for reference. Figures 1-4 According to the centrifugal fan of the present invention, a turbulence element 5 is provided at one end of the blade 2 near the air inlet of the airflow channel 6. The turbulence element 5 disperses the airflow and causes the airflow to act on the initial separation point of the leading edge of the blade 2. By enhancing the boundary layer turbulence intensity and momentum mixing near the separation zone, flow separation is suppressed, thereby improving the efficiency of the fan and reducing aerodynamic noise.

[0036] like Figures 1-4 As shown, a centrifugal fan according to one embodiment of the present invention includes: a volute.

[0037] The volute is provided with an accommodating cavity, and the volute is provided with an air outlet which is communicated with the outside of the accommodating cavity.

[0038] The centrifugal fan further comprises a volute tongue which is arranged at the air outlet and is mainly used for preventing the gas from circulating in the volute.

[0039] In addition, the centrifugal fan further comprises an impeller 1 which is rotatably arranged in the accommodating cavity and is driven by a motor. The impeller 1 comprises a hub 3, a cover 4 and a plurality of blades 2. The blades 2 are arc-shaped blades. The hub 3 and the cover 4 are arranged in the axial direction of the impeller 1. The blades 2 are connected between the hub 3 and the cover 4. The plurality of blades 2 are arranged in the circumferential direction of the impeller 1 and surround a central cavity. An airflow channel 6 is formed between adjacent blades 2 and is used for connecting the central cavity and the outside of the impeller 1.

[0040] Referring to Figure 1 , Figure 3 and Figure 4 , each blade 2 of the impeller 1 is arc-shaped. The arc-shaped blade 2 comprises a concave surface and a convex surface. The concave surface is a pressure surface 22, and the convex surface is a suction surface 21. The plurality of blades 2 are arranged in the circumferential direction of the impeller 1. The plurality of blades 2 have the same curvature, and the suction surface 21 and the pressure surface 22 of adjacent blades 2 are opposite to each other. The arc-shaped blades 2 can reduce the flow resistance of the gas and improve the efficiency of the centrifugal fan. The arc-shaped design can make the distribution of the gas on the blades 2 more uniform, thereby reducing the vortex and turbulence of the gas and improving the stability of the centrifugal fan. The plurality of blades 2 surround the central cavity. When the impeller 1 rotates, as shown in Figure 1 and Figure 3 , the shearing head indicates that the impeller 1 rotates counterclockwise. The gas flows from the central cavity to the airflow channel 6 formed by adjacent two blades 2 and then flows to the air outlet through the airflow channel 6.

[0041] The airflow flows past the volute tongue. The volute tongue divides the airflow into two parts. Most of the airflow flows to the air outlet along the airflow channel 6, and a small part of the airflow flows back to the volute through the gap between the volute tongue and the impeller 1. After rotating one circle in the volute with the impeller 1, the small part of the airflow returns to the volute tongue to participate in the new flow division.

[0042] The volute tongue is greatly affected by pressure fluctuation, and belongs to the expansion section, and the static pressure is greater, resulting in poor airflow flow. When the airflow flow is poor, backflow will be generated at the corresponding airflow passage 6, thereby causing separation of the airflow from the leading edge of the arc-shaped blade 2. Of course, when the pressure fluctuation of the airflow at other positions is large, separation of the airflow from the suction surface 21 of the corresponding blade 2 at other positions will also be caused. In general, the separation of the airflow near the volute tongue from the suction surface 21 is greater than that of the airflow at other positions from the suction surface 21.

[0043] The disturbance member 5 is arranged at one end of each blade 2 near the central cavity. Part of the airflow in the central cavity is adapted to enter the airflow passage 6 after being disturbed and dispersed by the disturbance member 5. After the airflow passes through the disturbance member 5, the airflow flows to the suction surface 21 through the wake of the disturbance member 5. At this time, the airflow acts on the leading edge of the suction surface 21 of the blade 2, and the leading edge refers to one end of the blade 2 near the central cavity. Therefore, the boundary layer turbulence intensity and momentum mixing near the separation zone of the airflow and the suction surface 21 are enhanced to suppress flow separation, thereby improving the efficiency of the centrifugal fan and reducing aerodynamic noise.

[0044] Referring to Figure 1 As shown in the figure, the wheel cover 4 includes an inner fixed ring 42 and an outer fixed ring 41, and the outer fixed ring 41 is located at the outer periphery of the inner fixed ring 42. That is, the two sides of the blade 2 in the radial direction of the impeller 1 are connected to the inner fixed ring 42 and the outer fixed ring 41 respectively, so that both sides of the blade 2 can be fixed, and the arrangement of the plurality of blades 2 can be easily observed.

[0045] Further, one side of the blade 2 near the central cavity is connected to the inner fixed ring 42, and the other side away from the central cavity is connected to the outer fixed ring 41, and the disturbance member 5 is connected between the inner fixed ring 42 and the hub 3.

[0046] The inner fixed ring 42 is connected to the blade 2 and the disturbance member 5 on the two sides in the radial direction, so that the blade 2 and the disturbance member 5 are spaced apart and distributed, and the disturbance member 5 is located on one side of the blade 2 near the central cavity, and the disturbance member 5 can be fixed. When the airflow flows to the airflow passage 6, the airflow can flow around the disturbance member 5, and in the process of flowing, due to the distance between the disturbance member 5 and the blade 2, the airflow can continue to flow to the edge of the suction surface 21 along the space between the disturbance member 5 and the blade 2, thereby reducing the separation of the gas from the edge of the suction surface 21.

[0047] In addition, the two sides of the inner fixed ring 42 in the radial direction are respectively configured as an inner wall surface 422 and an outer wall surface 421. The blade 2 is connected between the outer wall surface 421 and the outer fixed ring 41, and the disturbance member 5 is connected to the inner wall surface 422 or the side of the inner fixed ring 42 facing the hub 3.

[0048] Referring to Figure 1As shown, the spoiler 5 is connected to the inner wall surface 422 of the inner fixed ring 42, one side of the blade 2 is connected to the outer wall surface 421 of the inner fixed ring 42, and the spoiler 5 is connected to the hub 3 along the axial direction of the impeller 1. By connecting the spoiler 5 to the inner wall surface 422 and the outer wall surface 421 of the inner fixed ring 42, the spoiler 5 is spaced apart from the blade 2, and the distance between them is the thickness of the inner fixed ring 42 along the radial direction of the impeller 1.

[0049] When the blade 2 is connected to the inner fixed ring 42, it is convenient to determine the connection position of the spoiler 5 through the inner fixed ring 42, and it is also convenient to connect the spoiler 5. It is easy to observe the positional relationship between the blade 2 and the spoiler 5, and the positional relationship between the plurality of spoilers 5 and the corresponding plurality of blades 2 can be the same, so that the degree of disturbance of the spoiler 5 to the airflow is the same when the airflow flows to each group of airflow passages 6, thereby reducing the turbulence degree of the airflow, and each spoiler 5 can increase the turbulence intensity and momentum mixing at the edge of the corresponding blade 2 to suppress flow separation.

[0050] Of course, the spoiler 5 can also be fixedly connected to the side of the inner fixed ring 42 close to the hub 3 in the axial direction, so that the adjacent blades 2 can be disturbed by the spoiler 5 within the range of the axial direction of the inlet, thereby improving the turbulence intensity and momentum mixing effect at the front edge of the blade 2, thereby reducing the separation between the airflow and the edge of the blade 2.

[0051] Referring to Figure 4 As shown, the distance between the spoiler 5 and the blade 2 is L, and satisfies: 2mm≤L≤3mm.

[0052] Wherein, the distance between the spoiler 5 and the blade 2 should not be too far, such as too far, the airflow continues to disperse after passing through the spoiler 5, so that it cannot smoothly contact the front edge of the blade 2, and the inlet airflow passage 6 may be kept at a distance from the suction surface 21. The front edge of the blade 2 is the edge of the blade 2 close to the center cavity, and the front edge of the blade 2 close to the center cavity is designed with an arc, and the influence of the adverse pressure gradient of the airflow causes the airflow to backflow. In the process of backflow, it is easy to separate between the front edge of the blade 2.

[0053] That is, by limiting the position of the spoiler 5, the spoiler 5 can not only disturb the airflow, but also make the disturbed airflow reach the front edge of the blade 2 at a closer distance, thereby reducing the noise caused by the separation of the airflow at the front edge of the blade 2. That is, the distance between the spoiler 5 and the blade 2 is set to be between 2-3mm, which can satisfy the airflow flowing to the front edge of the blade 2 more smoothly and closer, such as the distance between the spoiler 5 and the blade 2 close to the center cavity can be 2mm, 2.2mm, 2.5mm and 3mm, etc.

[0054] With reference to the drawings Figure 4 As shown, the spoiler 5 is configured as a cylinder, the radius of the cylinder is r, the thickness of the blade 2 along the circumferential direction of the impeller 1 is d, and it satisfies: 30% d≤r≤50% d.

[0055] By designing the spoiler 5 as a cylinder, the flow resistance of the airflow is reduced, and after the airflow passes through one side of the cylindrical spoiler 5, it can reach the edge of the suction surface 21 more evenly and smoothly.

[0056] The radius of the spoiler 5 should not be too large. When the radius of the spoiler 5 is too large, the airflow passing through one side of the spoiler 5 does not contact the front edge of the blade 2 and enters the airflow passage 6, so the airflow intensity at the front edge of the blade 2 cannot be enhanced, and the effect of inhibiting the separation of the airflow from the end edge of the suction surface 21 is poor. By limiting the radius range of the cylindrical spoiler 5, it can be ensured that the airflow passing through one side of the spoiler 5 at least smoothly contacts the front edge of the arc-shaped blade 2, that is, the airflow after being disturbed by the spoiler can enhance the turbulence intensity and momentum mixing of the boundary layer near the separation zone, thereby better inhibiting the separation between the airflow and the suction surface 21.

[0057] Therefore, by setting the radius of the spoiler 5 to be 30%-50% of the thickness of the blade 2, where the thickness of the blade 2 is in mm, the blocking effect of the spoiler 5 on the airflow at the front end of the blade 2 is reduced, and at the same time, the spoiler 5 can disperse and disturb the airflow at the front end of the blade 2, so that the airflow flows along the wake of the spoiler 5 to the front edge of the blade 2, thereby appropriately increasing the airflow at the edge of the suction surface 21 of the blade 2, reducing the separation of the airflow from the edge, and thereby reducing the noise of the centrifugal fan.

[0058] Figure 4 In the embodiment, each spoiler 5 is located at the central position along the circumferential direction of the corresponding blade 2. When the spoiler 5 is located at the central position along the circumferential direction of the corresponding blade 2, the airflow can flow to the edge of the suction surface 21 of the blade 2 after passing through one side of the spoiler 5, and flow from the edge of the suction surface 21 to the airflow passage 6, and at the same time, the airflow also enters the adjacent airflow passage 6 through the other side of the spoiler 5, thereby making the airflow entering the adjacent airflow passage 6 more uniform after passing through the spoiler 5, that is, while inhibiting the separation of the airflow from the leading edge of the blade 2, the uniformity of the airflow flow can also be improved.

[0059] In addition, one end of the blade 2 close to the central cavity is configured as an arc-shaped structure 23. Then, after being disturbed by the spoiler 5, the airflow flows along the leading edge of the blade 2 of the arc-shaped structure 23, improving the smoothness of the flow, thereby reducing the influence of airflow resistance, so that the airflow can flow along the surface of the arc-shaped structure 23 to the airflow passage 6, thereby reducing the separation between the airflow and the suction surface 21 during airflow.

[0060] Combination Figure 1 and Figure 2 As shown, the blades 2 and the baffle 5 have the same length along the axial direction of the impeller 1. The baffle 5 extends along the axial direction of the impeller 1, and the blades 2 also extend along the axial direction. When the gas enters the airflow channel 6 formed between adjacent blades 2, the baffle 5 can turbulent the airflow on the side of the blade 2 near the central cavity along the axial direction of the impeller 1. Thus, along the axial direction of the impeller 1, the edge of the suction surface 21 of the blade 2 is enhanced with airflow, thereby reducing the separation between the suction surface 21 of the entire blade 2 and the airflow, and further reducing noise.

[0061] Reference Figure 2 As shown, the axial thickness of the wheel cover 4 is greater than the axial thickness of the wheel hub 3. That is... Figure 2 In this context, t1 represents the thickness of the wheel cover 4, and t2 represents the thickness of the hub 3, so t1 > t2. The distance between the end of the wheel cover 4 away from the hub 3 and the end of the hub 3 away from the wheel cover 4 is h, which is the axial length of the entire impeller 1. The hub 3 can serve as a support surface for multiple blades 2, and the area of ​​the hub 3 is large enough to connect multiple blades 2 and improve the stability and strength of the connection between multiple blades 2. The wheel cover 4 has a large thickness along the axial direction, which can improve the strength of the wheel cover 4 and facilitate the simultaneous connection of the wheel cover 4 with the blades 2 and the baffle 5, ensuring the stability of the baffle 5 and the blades 2.

[0062] Additionally, it should be noted that the spoiler 5 at the leading edge of blade 2 is a micro-cylinder. The micro-cylinder can be evenly distributed near the leading edge of the non-working surface (suction surface 21) of blade 2, and its design parameters include position parameters and size parameters.

[0063] Reasonable positional parameters enable the wake region of the microcylinder to act directly on the initial separation point of the non-working front edge of blade 2, thereby suppressing flow separation by enhancing the boundary layer turbulence intensity and momentum mixing near the separation region. The introduction of the microcylinder will increase flow resistance and aerodynamic losses to a certain extent. Its design parameters not only affect the suppression effect of flow separation, but also affect the efficiency of the fan. Therefore, it is necessary to optimize the design parameters of the microcylinder.

[0064] During the design process, the design variables of the micro-cylinder, such as the design range of position parameters, length, and radius, are determined. The sample space is obtained through Latin hypercube sampling, which is a method of approximately random sampling from a multivariate parameter distribution. It belongs to the stratified sampling technique and aims to ensure that sample points are evenly distributed at different levels of multiple variables.

[0065] Then the sample space is calculated by CFD, CFD is a kind of science for solving fluid flow related problems by mathematical calculation and computer technology, and the output fan efficiency is taken as the optimization target, and the function relationship between design variables and optimization target is established by using Kriging surrogate model;Kriging surrogate model is a kind of regression analysis tool based on statistics, which is usually used to establish the mapping relationship between input and output variables, and supports uncertainty measurement and hypothesis testing.

[0066] The function relationship is optimized based on sequential quadratic programming to obtain the fan efficiency optimal point and the corresponding design variable;According to the micro-cylinder design parameters of the optimal position, the micro-cylinder fixing ring structure, that is, the structure of the inner fixing ring 42, is designed.

[0067] Moreover, according to the boundary layer theory, the larger adverse pressure gradient on the suction surface 21 side of the short blade 2 channel and the larger adverse pressure gradient of the multi-wing centrifugal fan are the important reasons for the initial separation of the blade 2 leading edge, the micro-cylinder is arranged at the leading edge position, the micro-cylinder wake acts on the initial separation point of the blade 2 leading edge, the boundary layer turbulence intensity and momentum mixing near the separation zone are enhanced to suppress flow separation;In the simulation experiment, by comparing the original fan with the cross section turbulent kinetic energy and entropy production rate of the fan with the leading edge micro-cylinder, it can be seen that the blade 2 leading edge boundary layer turbulence intensity of the fan with the leading edge micro-cylinder is obviously enhanced, which is conducive to suppressing the flow separation of the blade 2 leading edge and expanding the high efficiency operation interval of the centrifugal fan. At the same time, the entropy production rate is used to represent the irreversible loss, and the impeller 1 with the leading edge micro-cylinder can effectively weaken the high loss area on the suction surface 21 side of the blade 2, which is an important reason for improving the fan efficiency. The final result shows that compared with the original fan, the centrifugal fan with the leading edge micro-cylinder improves the efficiency by 2.5% under the same working condition.

[0068] It should be pointed out that the fixing form of the micro-cylinder is not limited to the above-mentioned form, according to the actual fan size and structural strength, the connection form of the micro-cylinder and the blade 2 can be appropriately adjusted, or the number of the inner fixing ring 42 along the axial direction of the impeller 1 can be adjusted;In addition, the embodiment of the utility model takes the micro-cylinder as an example to illustrate the flow field adjusting effect of the spoiler 5 of the blade 2 leading edge, but the cross-sectional shape of the spoiler 5 is not limited to a circle, and the changes made on the basis of the micro-cylinder also belong to the protection scope of the embodiment of the utility model.

[0069] The embodiment of the utility model also discloses a kind of air conditioner, including the centrifugal fan described above, and the spoiler 5 is arranged at one end of blade 2 close to the inlet of airflow passage 6, the spoiler 5 disperses airflow and makes airflow act on the initial separation point of blade 2 leading edge, by enhancing the turbulence intensity and momentum mixing of boundary layer near separation zone to suppress flow separation, thereby improving the efficiency of fan and reducing aerodynamic noise, thereby improving the user experience of air conditioner.

[0070] 1. In the description of the present application, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0071] 2. In the description of the present application, "first feature" and "second feature" can include one or more features.

[0072] 3. In the description of the present application, "a plurality of" means two or more.

[0073] 4. In the description of the present application, "above" or "below" the first feature in the second feature can include direct contact between the first and second features, or can include indirect contact between the first and second features through another feature therebetween.

[0074] 5. In the description of the present application, "above", "above" and "above" of the first feature in the second feature include the first feature directly above and obliquely above the second feature, or only indicate that the first feature is higher than the second feature in horizontal height.

[0075] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0076] Although embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A centrifugal fan characterized by comprising: The centrifugal fan comprises: a volute, which is provided with a containing cavity and an air outlet communicating with the outside of the containing cavity; a volute tongue arranged at the air outlet; a impeller rotatably arranged in the containing cavity, which comprises a hub, a cover and a plurality of blades, the blades are arranged in an arc shape, the hub and the cover are arranged opposite along the axial direction of the impeller, the blades are connected between the hub and the cover, the plurality of blades are arranged in a spaced manner along the circumferential direction of the impeller, and the plurality of blades enclose a central cavity, the adjacent blades form an airflow channel for communicating the central cavity with the outside of the impeller; wherein each blade is provided with a spoiler at one end close to the central cavity, and part of the airflow in the central cavity is adapted to enter the airflow channel after being disturbed by the spoiler.

2. The centrifugal fan of claim 1, wherein The cover comprises an inner fixed ring and an outer fixed ring, and the outer fixed ring is located at the outer periphery of the inner fixed ring. The blade is connected to the inner fixed ring at one side close to the central cavity and connected to the outer fixed ring at one side away from the central cavity, and the spoiler is connected between the inner fixed ring and the hub.

3. The centrifugal fan of claim 2, wherein The inner fixed ring is provided with an inner wall surface and an outer wall surface on two sides in the radial direction, the blade is connected between the outer wall surface and the outer fixed ring, and the spoiler is connected to one side of the inner fixed ring or the inner fixed ring facing the hub.

4. The centrifugal fan of claim 1, wherein The distance between the spoiler and the blade is L, and 2mm≤L≤3mm is satisfied.

5. The centrifugal fan of claim 1, wherein The spoiler is in the shape of a cylinder, the radius of the cylinder is r, the thickness of the blade along the circumferential direction of the impeller is d, and 30% d≤r≤50% d is satisfied.

6. The centrifugal fan of claim 1, wherein Each spoiler is located at the central position of the corresponding blade along the circumferential direction.

7. The centrifugal fan of claim 1, wherein The end of the blade close to the central cavity is in the shape of an arc structure.

8. The centrifugal fan of claim 1, wherein The length of the blade and the length of the spoiler along the axial direction of the impeller are the same.

9. The centrifugal fan of claim 1, wherein The thickness of the cover along the axial direction is greater than the thickness of the hub along the axial direction.

10. An air conditioner characterized by comprising: The centrifugal fan according to any one of claims 1-9 is provided.

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