Axial flow fan air guide ring and axial flow fan

Abstract

The present application relates to an air guide ring for an axial flow fan, wherein a groove portion (104) is provided on a body (103) of the air guide ring (101), the groove portion (104) being located at a position on the body (103) closest to an axial projection line (501) of a blade tip (107) of a blade (106) of the axial flow fan, and the groove portion (104) extends circumferentially along an inner surface (105) of the body (103). The groove portion (104) is provided with a plurality of grooves, wherein each groove has a relatively deep radial depth and a relatively small axial height. The groove arrangement of the above structure can effectively reduce the leakage of air from the pressure surface of the blade (106) to the suction surface at the blade tip (107), thereby improving the overall performance of the axial flow fan system and reducing the noise of the fan system.

Description

Technical Field

[0001] The present application relates to the technical field of axial flow fans, and more specifically, to an air guide ring for an axial flow fan, and an axial flow fan having the air guide ring. Background Art

[0002] When an axial flow fan is in operation, air typically flows from one side of the fan to the other, along the direction of the fan's axis of rotation. This convergent flow of air creates a pressure differential between the two sides of the fan blades, manifesting as a pressure surface in the high-pressure area of ​​the blades and a suction surface in the low-pressure area of ​​the blades. Due to the gap between the blades and the air guide ring, the air at the blade tips is affected by the pressure differential and naturally flows from the pressure surface to the suction surface, resulting in tip leakage. Tip leakage in axial flow fans can reduce fan performance and cause noise.

[0003] Current production processes often reduce the amount of air leakage from the blade tips by reducing the gap between the blades and the air guide ring. However, this measure places high demands on the accuracy of the motor and the processing accuracy of the blades and air guide ring, increasing production and processing costs. Summary of the Invention

[0004] One of the purposes of the present application is to provide an improved air guide ring structure of an axial flow fan, which can effectively improve blade tip leakage.

[0005] In order to achieve the above objectives, the first aspect of the present application provides an air guide ring for an axial flow fan, which is rotationally symmetrical around the rotation axis of the impeller of the axial flow fan; the air guide ring includes a main body and a groove portion, the groove portion is arranged on the inner surface of the main body, and the groove portion extends circumferentially along the inner surface of the main body; the blade tip of the impeller blade forms an axial plane projection line on any cutting surface including the rotation axis, and the inner surface of the main body has a minimum spacing portion closest to the axial plane projection line; the position of the groove portion on the inner surface is set so that the minimum spacing portion is located within the groove portion; and the axial height M of the groove portion occupies a part of the axial height of the main body, and the axial height M of the groove portion is greater than or equal to 1 / 6 of the axial height of the main body, and less than or equal to 2 / 3 of the axial height of the main body.

[0006] As described above, in the air guide ring for the axial flow fan, the inner surface is convex toward the direction of the rotation axis.

[0007] As described above for the air guide ring for the axial flow fan, the minimum spacing portion is approximately located in the middle of the groove portion.

[0008] As described above, in the air guide ring for the axial flow fan, the groove portion has a plurality of grooves.

[0009] As described above, in the air guide ring for the axial flow fan, the radial depth D of each groove is greater than or equal to 2% of the blade radius of the axial flow fan and less than or equal to 7% of the blade radius of the axial flow fan.

[0010] As described above, in the air guide ring for the axial flow fan, each of the grooves has an opening, and an axial height H of the opening is greater than or equal to 0.3 mm and less than or equal to 5 mm.

[0011] As described above, in the air guide ring for the axial flow fan, the groove portion has three or more grooves.

[0012] As described above, in the air guide ring for the axial flow fan, the groove portion has a plurality of closed annular grooves or a plurality of spiral grooves.

[0013] A second aspect of the present application is to provide an axial flow fan, which includes an air guide ring and an impeller. The air guide ring is any one of the air guide rings for an axial flow fan described above in the present application.

[0014] The third aspect of the present application is to provide an air guide ring for an axial flow fan, which is rotationally symmetrical around the rotation axis of the impeller of the axial flow fan; the air guide ring includes a main body and a groove portion, the groove portion is arranged on the inner surface of the main body, the groove portion extends circumferentially along the inner surface of the main body, the axial cross-section of the main body and the inner surface have an intersection line, and the intersection line is a straight line; the axial height M of the groove portion occupies a part of the axial height of the main body, the axial height M of the groove portion is greater than or equal to 1 / 6 of the axial height of the main body, and less than or equal to 2 / 3 of the axial height of the main body; and the groove portion has a plurality of grooves.

[0015] According to the air guide ring for an axial flow fan of the third aspect of the present application, the radial depth D of each of the grooves is greater than or equal to 2% of the blade radius of the axial flow fan, and less than or equal to 7% of the blade radius of the axial flow fan; each of the grooves has an opening, and the axial height H of the opening is greater than or equal to 0.3 mm and less than or equal to 5 mm.

[0016] According to the air guide ring for an axial flow fan according to the third aspect of the present application, the groove portion has more than three grooves.

[0017] According to the third aspect of the present application, the air guide ring for an axial flow fan, the tip of the impeller blade forms an axial projection line on any cutting surface including the rotation axis, the axial projection line is a straight line, and the distance between the axial projection line and the intersection line is equal everywhere, and the position of the groove portion on the inner surface is set so that the axial midpoint of the body is located in the groove portion.

[0018] According to the air guide ring for an axial flow fan according to the third aspect of the present application, the groove portion extends from any axial end of the body, from a position 0.3 times the axial height of the body to a position 0.7 times the axial height of the body.

[0019] According to the third aspect of the present application, the air guide ring for an axial flow fan, the blade tip of the axial flow fan blade forms an axial plane projection line on any cutting surface including the rotation axis, the inner surface of the body has a minimum spacing portion closest to the axial plane projection line, and the position of the groove portion on the inner surface is set so that the minimum spacing portion is located within the groove portion.

[0020] According to the air guide ring for an axial flow fan according to the third aspect of the present application, the minimum spacing portion is approximately located in the middle of the groove portion.

[0021] According to the air guide ring for an axial flow fan of the third aspect of the present application, the groove portion has a plurality of closed annular grooves or a plurality of turns of spiral grooves.

[0022] The fourth aspect of the present application is to provide an axial flow fan, which includes an air guide ring and an impeller. The air guide ring is any one of the air guide rings for an axial flow fan described in the fourth aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the three-dimensional structure of an axial flow fan having an air guide ring according to an embodiment of the present application;

[0024] Figure 2 for Figure 1 A top view of the axial flow fan is shown;

[0025] Figure 3 for Figure 2 A cross-sectional view of the axial flow fan along the AA direction is shown;

[0026] Figure 4 for Figure 3 A partial enlarged view of area B of the axial flow fan cross-sectional view shown;

[0027] Figure 5 for Figure 4 A schematic diagram of the axial position of the groove portion of the air guide ring shown;

[0028] Figure 6 A schematic diagram of the axial position of the groove portion of the air guide ring according to another embodiment of the present application;

[0029] Figure 7 To have Figure 6 Schematic diagram of an axial flow fan with an air guide ring shown;

[0030] Figure 8A The first embodiment of the cross-sectional shape of the groove of the air guide ring is shown;

[0031] Figure 8B A second embodiment of the cross-sectional shape of the groove of the air guide ring is shown;

[0032] Figure 8C A third embodiment of the cross-sectional shape of the groove of the air guide ring is shown;

[0033] Figure 9A A first embodiment of the circumferential distribution pattern of the grooves is shown;

[0034] Figure 9B A second embodiment of the circumferential distribution pattern of the grooves is shown;

[0035] Figure 10A A first embodiment of the radial distribution pattern of grooves is shown;

[0036] Figure 10B A second embodiment of the radial distribution pattern of grooves is shown;

[0037] Figure 11 for Figure 4 The specific structural diagram of the groove portion of the air guide ring is shown;

[0038] Figure 12 for Figure 6 A schematic diagram of the axial position of the groove portion of the air guide ring shown;

[0039] Figure 13 The static pressure efficiency of an axial flow fan with a slotless air guide ring and an axial flow fan with a slotted air guide ring according to Example 1 of the present application at different air volumes was compared.

[0040] Figure 14 The shaft power of an axial flow fan with a slotless air guide ring and an axial flow fan with a slotted air guide ring according to Example 1 of the present application at different air volumes was compared. DETAILED DESCRIPTION

[0041] Various specific embodiments of the present application will be described below with reference to the accompanying drawings that form a part of this specification. It should be understood that although terms indicating directions, such as "front", "rear", "up", "down", "left", "right", etc., are used in this application to describe various example structural parts and elements of the present application, these terms are used here only for the purpose of convenience of explanation and are determined based on the example orientations shown in the accompanying drawings. Since the embodiments disclosed in this application can be set in different directions, these directional terms are only for illustration and should not be regarded as limitations. Where possible, the same or similar figure numbers used in this application refer to the same parts.

[0042] Figure 1 The axial flow fan 100 is shown in a three-dimensional structure. The axial flow fan 100 has an air guide ring 101 according to an embodiment of the present application. Figure 1 As shown, the axial flow fan 100 includes an impeller 110 and an air guide ring 101, and the air guide ring 101 rotates around the rotation axis 130 of the impeller 110 (see Figure 3 ) is rotationally symmetrical. The impeller 110 has a number of blades 106 arranged around its hub 102, and the hub 102 is connected to a motor (not shown) for driving the impeller 110 to rotate. During the rotation of the impeller 110, the air fluid flows from the bottom of the axial flow fan 100 to the top of the axial flow fan 100, thereby forming a pressure difference between the upper surface and the lower surface of the blade 106, wherein the pressure on the upper surface is greater, which is the pressure surface, and the pressure on the lower surface is smaller, which is the suction surface. Due to the gap between the blade 106 and the air guide ring 101, when there is a pressure difference between the upper surface and the lower surface of the blade 106, the wind will inevitably flow from the pressure surface of the blade 106 to the suction surface, thereby causing leakage. In order to alleviate the above leakage, the air guide ring 101 of the present application is provided with a groove portion 104 on its body 103, and the groove portion 104 extends circumferentially along the inner surface 105 of the body 103.

[0043] Figure 2 Shown Figure 1 The top view of the axial flow fan 100 is shown. Among them, the outer edge of the blade 106 farthest from the hub 102 is the blade tip 107. Compared with other parts of the blade 106, the blade tip 107 is closest to the air guide ring 101.

[0044] Figure 3 for Figure 2 The sectional view of the axial flow fan 100 along the AA direction is shown. Figure 3 As shown, in the radial direction of the axial flow fan 100 (ie, a direction perpendicular to the impeller rotation axis 130 ), the groove portion 104 of the air guide ring 101 extends from the inner surface 105 of the body 103 toward the interior of the body 103 . Figure 3 The inner surface 105 of the body 103 shown in FIG. 1 is convex toward the rotation axis 130, so that the intersection line of the cross section along the AA direction (i.e., the cross section including the rotation axis 130) and the inner surface 105 is an arc. In other embodiments, the inner surface 105 may not be convex toward the rotation axis 130. For example, the intersection line of the cross section including the rotation axis 130 and the inner surface 105 is a straight line.

[0045] Figure 4 for Figure 3 The enlarged view of the circled area B shows more clearly Figure 3 The structure of the middle air guide ring 101 in the groove portion 104 area. Figure 4As shown, the groove portion 104 includes a plurality of grooves 401, each groove 401 forming a ring around the rotation axis 130 of the impeller 110, the central axis of the ring substantially coinciding with the rotation axis 130 of the impeller 110, each groove 401 being perpendicular to the impeller rotation axis 130 along the radial extension direction of the axial flow fan 100, and the axial cross-section of each groove 401 being substantially rectangular. However, in other embodiments, the grooves may be arranged in other ways. At the pressure surface (i.e., the upper surface) of the blade tip 107, the pressure and velocity of the air fluid are high. The arrangement of the groove portion 104 allows the air fluid leaking from the blade tip to enter the groove portion 104 under the action of centrifugal force. On the one hand, since the product of the fluid's rotational diameter and velocity remains constant, when the airflow leaves the blade and enters the groove portion 104, the velocity of the fluid decreases as the rotational diameter increases. On the other hand, at the tip 107, there is a vortex in the airflow leaving the blade. When the vortex enters the groove 104, there is dissipation inside the airflow, which effectively reduces the vortex degree, that is, the turbulence intensity, and buffers the leakage flow of the fluid.

[0046] Figure 5 FIG. 1 shows how to determine the position of the groove portion 104 in the axial direction of the air guide ring 101. Figure 5 As shown, the air guide ring 101 is hypothetically cut by a plane including the rotation axis 130 to obtain an axial section 510 of the air guide ring. The tip 107 of the blade 106 forms an axial projection line 501 on the hypothetical plane including the rotation axis 130. The axial projection line 501 can also be regarded as a trajectory line formed by the tip 107 of the blade 106 on the plane when the blade 106 rotates through the plane including the rotation axis 130. Specifically, since the blade 106 has a certain curvature, the tip 107 of the blade 106 extends a certain distance in the axial direction of the air guide ring 101. Therefore, when the blade 106 rotates through the plane including the rotation axis 130, the intersection of each point on the tip 107 and the plane will form a continuous trajectory line on the plane, and the trajectory line is the axial projection line 501. Since the air guide ring 101 is rotationally symmetrical, the blade tip 107 of the blade 106 can form an axial projection line 501 on any plane including the rotation axis 130 . Figure 5 The axial projection line 501 shown in FIG is an arc line. In other embodiments, the axial projection line 501 may also be a straight line. The specific shape of the axial projection line 501 is determined by the shape of the blade 106.

[0047] When the plane including the rotation axis 130 cuts the air guide ring 101, there is an intersection line 503 between the plane including the rotation axis 130 and the inner surface 105 of the air guide ring 101. The intersection line 503 is also the intersection line between the axial section 510 of the air guide ring and the inner surface 105. Figure 5It can be seen that the intersection line 503 has a minimum spacing portion 502 closest to the axial projection line 501. The groove portion 104 is arranged at the position of the minimum spacing portion 502. Figure 5 As shown, the inner surface 105 of the air guide ring 101 is convex in the middle, so the intersection line 503 of the axial section 510 of the air guide ring and the inner surface 105 is an arc curve. Figure 5 In the shape shown, the minimum spacing portion 502 on the intersection line 503 is a point. In this case, the minimum spacing portion 502 is located within the groove portion 104, for example, in the middle of the groove portion 104. In some embodiments, the inner surface 105 of the air guide ring 101 and the blade tip 107 of the blade 106 can have other shapes. The intersection line 503 and the axial projection line 501 formed by them make the minimum spacing portion 502 a segment. In this case, the groove portion 104 is configured so that the segment is located within the groove portion 104.

[0048] Positioning the groove 104 at the minimum clearance portion 502 maximizes the groove's buffering effect on blade tip leakage. When the blade 106 rotates, the pressure differential between the pressure and suction sides of the blade 106 is greatest at the point where the blade tip 107 is closest to the inner surface 105 of the air guide ring 101, and tip leakage is most severe. When the groove 104 is closest to the rotating blade tip 107 on the air guide ring 101, its two sides abut the high-pressure area on the pressure side and the low-pressure area on the suction side of the blade 106, respectively. This arrangement mitigates the high-pressure-low-pressure pressure gradient in the tip clearance region, reduces the turbulent flow intensity, and buffers the flow from the pressure side to the suction side of the blade. Therefore, positioning the groove 104 on the inner surface 105 of the air guide ring 101 closest to the axial projection line 501 of the blade tip 107 helps maximize its buffering effect on blade tip leakage.

[0049] In other embodiments, the inner surface 105 of the air guide ring 101 and the blade tip 107 of the blade 106 can also be other shapes, and the distance between the intersection line 503 formed and the axial projection line 501 is equal everywhere, so that there is no minimum spacing part on the intersection line 503.

[0050] Figure 6An embodiment is shown in which there is no minimum spacing between the axial projection line 501 of the blade tip 107 and the inner surface 105 of the air guide ring 101. In this embodiment, the shape of the blade 106 causes the axial projection line 501 of the blade tip 107 to be a straight line. The shape of the air guide ring 101 causes the intersection line 503 between its inner surface 105 and the air guide ring axial cross section 510 to be a straight line as well, with the distance between the intersection line 503 and the axial projection line 501 being the same at all locations. In this case, there is no minimum spacing portion 502 closest to the axial projection line 501 on the intersection line 503, and the groove portion 104 is positioned approximately in the middle of the axial direction of the air guide ring 101.

[0051] Figure 7 Shown with Figure 6 Axial flow fan with air guide ring. Figure 7 As shown, due to Figure 6 The intersection line of the axial projection line 501 of the blade tip 107 shown in FIG. 1 and the inner surface 105 of the air guide ring 101 is a straight line, so the inner surface 105 of the air guide ring 101 is in the shape of a vertical cylinder.

[0052] Figure 8A 、 8B 8 and 8C respectively show three embodiments of the cross-sectional shape of the groove. Figures 4 to 6 The axial cross-sections of the grooves 401 shown in the figures are all substantially rectangular. In other embodiments, the axial cross-sections of the grooves 401 may also be other shapes, for example, Figure 8A The axial cross section of the groove 401 shown is generally triangular. Figure 8B The axial cross section of the groove 401 shown is generally arched. Figure 8C The axial cross-section of the groove 401 shown is generally trapezoidal. Figures 8A to 8C The arrangement of the groove 401 shown in FIG is based on an air guide ring whose inner surface 105 is convex toward the rotation axis 130 . For air guide rings of other shapes, for example Figure 6 The air guide ring shown can also have Figures 8A to 8C The cross-sectional shape of the groove is shown in .

[0053] Figure 9A and 9B Schematic diagrams of the circumferential distribution patterns of grooves in two embodiments. Figures 4 to 6 The grooves 401 shown in the figure can have various circumferential distribution patterns. For example, Figure 9A A schematic diagram of a closed annular groove 901 is shown, that is, the groove portion 104 can be composed of a plurality of closed annular grooves 901; Figure 9B A schematic diagram of a multi-turn spiral groove 902 is shown, that is, the groove portion 104 can be composed of a multi-turn spiral groove 902.

[0054] Figure 10A and10B Two embodiments of radial distribution patterns of the grooves of the air guide ring are shown respectively. Figures 4 to 6 The grooves 401 shown in FIG are all perpendicular to the rotation axis 130 along the radial direction of the axial flow fan 100. In other embodiments, the grooves 401 may not be perpendicular to the rotation axis 130 along the radial direction of the axial flow fan 100. For example, Figure 10A and Figure 10B The examples of the groove 401 extending in the radial direction of the axial fan 100 and forming a certain inclination angle with the rotation axis 130 are respectively shown, wherein: Figure 10A The radial extension direction of the groove 401 shown in FIG is such that its opening direction is upward. Figure 10B The radial extension direction of the groove 401 shown in FIG. 4 is such that its opening is directed downward.

[0055] Figure 11 Shown Figure 4 Schematic diagram of the specific structure of the middle groove portion 104. Figure 11 As shown, the axial height of the opening of the groove portion 104 on the inner surface 105 of the air guide ring 101 is M. The axial height M of the groove portion 104 is required to cover the minimum spacing portion 502 on the inner surface 105 of the air guide ring 101. The axial height M of the groove portion 104 is greater than or equal to 1 / 6 of the axial height of the main body 103 of the air guide ring 101, and less than or equal to 2 / 3 of the axial height of the main body 103 of the air guide ring 101. Setting the axial height M of the groove portion 104 to occupy a portion of the axial height of the main body 103 is beneficial to reducing processing costs on the one hand, and ensuring the strength of the air guide ring on the other hand. If the groove portion is completely covered with the main body, the strength of the air guide ring will be greatly reduced. On the other hand, it is beneficial to optimize the aerodynamic performance of the air guide ring. If the air guide ring is axially covered with grooves, it is equivalent to reducing the actual overlapping length of the blade and the air guide ring, which in turn increases leakage at the blade tip.

[0056] like Figure 11 As shown, the axial height H of the opening of each groove 401 of the groove portion 104 on the inner surface 105 of the air guide ring 101 is greater than or equal to 0.3 mm and less than or equal to 5 mm. In other embodiments, the axial height H of the opening of the groove 401 can also be greater than or equal to 0.5 mm and less than or equal to 4 mm. The axial height H of the opening of the groove 401 should not be too large, otherwise it will cause excessive diffusion loss. Moreover, a too large axial height will increase the blade tip clearance and increase the tip leakage of the fluid.

[0057] Each groove 401 extends to a depth D in the radial direction of the axial flow fan 100. The radial depth D of the groove 401 is greater than or equal to 2% and less than or equal to 7% of the radius of the blade of the axial flow fan 100. The radial depth D of the groove 401 cannot be too shallow, otherwise the airflow leaking from the blade tip will immediately return after entering the slot, thereby increasing the turbulence intensity of the airflow.

[0058] Figure 11 The number of grooves 401 shown in FIG is 7. In other embodiments, the number of grooves 401 may be other values ​​greater than or equal to 3. The number of grooves 401 cannot be too small, because the provision of grooves 401 is equivalent to increasing the flow path of the tip leakage airflow. Too few grooves 401 will not effectively suppress leakage.

[0059] The interval between two adjacent grooves 401 is G, which is related to the axial height M of the groove portion 104, the axial height H of the groove 401, and the number of grooves 401. In some embodiments, the interval G between two adjacent grooves 401 is substantially the same as the axial height H of the groove 401 opening.

[0060] Based on Figure 11 The design of the groove portion 104 shown in FIG is similar to the principle, Figure 6 The groove portion 104 shown in FIG may also have Figure 11 Specifically, Figure 6 The axial height M of the opening of the groove portion 104 shown in the figure on the inner surface 105 of the air guide ring 101 is greater than or equal to 1 / 6 of the axial height of the body 103 of the air guide ring 101, and less than or equal to 2 / 3 of the axial height of the body 103 of the air guide ring 101. Figure 6 The axial height H of the opening of each groove 401 in the groove portion 104 shown on the inner surface 105 of the air guide ring 101 is greater than or equal to 0.3 mm and less than or equal to 5 mm; or greater than or equal to 0.5 mm and less than or equal to 4 mm. Figure 6 The extending depth D of each groove 401 in the radial direction of the axial flow fan 100 shown in FIG. 1 is greater than or equal to 2% of the blade radius of the axial flow fan 100 and less than or equal to 7% of the blade radius of the axial flow fan 100 . Figure 6 The number of the grooves 401 shown in FIG is 11. In other embodiments, the number of the grooves 401 may also be other values ​​greater than or equal to 3. Figure 6 The interval G between two adjacent grooves 401 shown in FIG is associated with the axial height M of the groove portion 104, the axial height H of the groove 401, and the number of grooves 401. In some embodiments, the interval G between two adjacent grooves 401 is substantially the same as the axial height H of the groove 401 opening.

[0061] Figure 12 Shown Figure 6 An embodiment of the axial height of the groove portion 104 at the inner surface 105 of the air guide ring 101. Figure 6 The axial height M of the opening of the groove portion 104 shown in FIG. 1 on the inner surface 105 of the air guide ring 101 is greater than or equal to 1 / 6 of the axial height of the body 103 of the air guide ring 101 and less than or equal to 2 / 3 of the axial height of the body 103 of the air guide ring 101. More specifically, Figure 6 The axial height M of the opening of the groove portion 104 on the inner surface 105 shown in the figure can be set to: from one axial end of the body 103 of the air guide ring 101, extend from a position 0.3 times the axial height X of the body 103 to a position 0.7 times the axial height X of the body 103. This setting enables the groove portion 104 to be located at the middle position of the axial direction of the air guide ring 101, and the axial height of the opening of the groove portion 104 on the inner surface 105 is 0.4 times the axial height of the air guide ring 101.

[0062] This application has been verified for performance through computer simulation software. Table 1 takes a certain axial flow fan with a diameter of 910 mm as an example, and compares the static pressure efficiency of the axial flow fan with a slotless air guide ring and an air guide ring with grooves at rated air volume. The inner surface of the air guide ring of the axial flow fan is convex in the direction of its rotation axis, and the axial projection of the blade tip of the axial flow fan is an arc. There is a minimum spacing portion closest to the axial projection of the blade on the inner surface of the axial flow fan. Among them, for examples 1 to 3 of the air guide ring with grooves, the axial cross-section of the grooves is rectangular, and the multiple grooves are all closed rings. The grooves are located at the position on the air guide ring closest to the axial projection of the blade. The specific structure and number of the grooves in different embodiments are different.

[0063] Table 1 Static pressure efficiency of axial flow fans under different types of air guide rings

[0064]

[0065] Table 1 shows that the static pressure efficiency of axial flow fans equipped with the grooved air guide rings of Examples 1 to 3 is significantly higher than that of axial flow fans equipped with conventional, non-grooved air guide rings. Among the grooved air guide rings, Example 1 has a greater number of grooves, a smaller axial height, and a similar average radial depth to the other examples, resulting in the highest static pressure efficiency.

[0066] Figure 13 The static pressure efficiency of the axial flow fan under different air volume conditions is compared under the action of the original slotless air guide ring shown in Table 1 and the slotted air guide ring of Example 1 of this application. Figure 13It can be seen that under the working air volume of the axial flow fan, the static pressure efficiency of the axial flow fan with the slotted air guide ring of Example 1 is always higher than the static pressure efficiency of the axial flow fan installed with the original slotless air guide ring.

[0067] Figure 14 The shaft power of the axial flow fan under different air volume conditions is compared under the action of the original slotless air guide ring shown in Table 1 and the slotted air guide ring of Example 1 of this application. Figure 14 It can be seen from the figure that, under the working air volume of the axial flow fan, the shaft power of the axial flow fan with the slotted air guide ring of Example 1 is always higher than the shaft power of the axial flow fan with the original slotless air guide ring installed.

[0068] The present application provides a plurality of grooves 401 on the air guide ring 101 of the axial flow fan 100, so that during the operation of the axial flow fan 100, the flow rate of air fluid flowing back from the pressure surface of the blade tip 107 to the suction surface through the gap between the blade tip 107 and the air guide ring 101 is reduced, thereby increasing the air flow rate transported by the blade. According to the power-air volume curve of the axial flow blade, under the same conditions, the medium flow rate transported by the blade increases, causing the blade operating point to shift toward a larger air volume. According to the power characteristics of the axial flow fan, an increase in the air volume at the operating point will reduce the energy consumption of the fan and improve the overall performance of the fan system. On the other hand, when there is a minimum spacing portion on the inner surface 105 of the air guide ring 101 that is closest to the axial projection 501 of the blade 106, multiple grooves 401 are set at the position on the air guide ring 101 that is closest to the axial projection line 501 of the blade 106. The drainage effect of the groove 401 alleviates the sharp change in the surface pressure gradient of the blade tip 107 in the thickness direction. After the high-speed flowing medium enters the groove 401, the flow cross-section increases, the speed and turbulence intensity decrease, and a part of the peeling vortex on the surface of the blade 106 also enters the groove 401, thereby reducing the noise of the axial flow fan system.

[0069] Although the present application will be described with reference to specific embodiments shown in the accompanying drawings, it should be understood that the air guide ring structure of the present application may be modified in many ways without departing from the spirit, scope, and context of the teachings of the present application. Those skilled in the art will also appreciate that there are many ways to modify the structural details of the embodiments disclosed in the present application, all of which fall within the spirit and scope of the present specification and claims.

Claims

1. An air guide ring for an axial flow fan, characterized in that: The air guide ring (101) is rotationally symmetrical around the rotation axis (130) of the impeller (110) of the axial flow fan (100); The air guide ring (101) comprises a body (103) and a groove portion (104), wherein the groove portion (104) is provided on an inner surface (105) of the body (103), and the groove portion (104) extends circumferentially along the inner surface (105) of the body (103); The blade tips (107) of the blades (106) of the impeller (110) form an axial projection line (501) on any cutting surface including the rotation axis (130), and the inner surface (105) of the body (103) has a minimum spacing portion (502) closest to the axial projection line (501); The position of the groove portion (104) on the inner surface (105) is set so that the minimum spacing portion (502) is located inside the groove portion (104), The groove portion (104) has a plurality of grooves (401), and the radial depth (D) of each groove (401) is greater than or equal to 2% of the blade radius of the axial flow fan (100) and less than or equal to 7% of the blade radius of the axial flow fan (100); and The axial height (M) of the groove portion (104) accounts for a portion of the axial height of the body (103), and the axial height (M) of the groove portion (104) is greater than or equal to 1 / 6 of the axial height of the body (103) and less than or equal to 2 / 3 of the axial height of the body (103).

2. The air guide ring for an axial flow fan according to claim 1, characterized in that: The inner surface (105) is convex in the direction of the rotation axis (130).

3. The air guide ring for an axial flow fan according to claim 1, characterized in that: The minimum spacing portion (502) is approximately located in the middle of the groove portion (104).

4. The air guide ring for an axial flow fan according to claim 1, characterized in that: Each of the grooves (401) has an opening, and an axial height (H) of the opening is greater than or equal to 0.3 mm and less than or equal to 5 mm.

5. The air guide ring for an axial flow fan according to claim 1, characterized in that: The groove portion (104) has three or more grooves (401).

6. The air guide ring for an axial flow fan according to claim 1, characterized in that: The groove portion (104) has a plurality of closed annular grooves (901) or a plurality of turns of spiral grooves (902).

7. An axial flow fan, the axial flow fan (100) comprising an air guide ring (101) and an impeller (110), characterized in that: The air guide ring (101) is the air guide ring (101) for an axial flow fan according to any one of claims 1 to 6.

8. An air guide ring for an axial flow fan, characterized in that: The air guide ring (101) is rotationally symmetrical around the rotation axis (130) of the impeller (110) of the axial flow fan (100); The air guide ring (101) comprises a body (103) and a groove portion (104), wherein the groove portion (104) is provided on an inner surface (105) of the body (103), and the groove portion (104) extends circumferentially along the inner surface (105) of the body (103); an axial cross section (510) of the body (103) and the inner surface (105) have an intersection line (503), and the intersection line (503) is a straight line; The axial height (M) of the groove portion (104) occupies a portion of the axial height of the body (103), and the axial height (M) of the groove portion (104) is greater than or equal to 1 / 6 of the axial height of the body (103) and less than or equal to 2 / 3 of the axial height of the body (103); and The groove portion (104) has a plurality of grooves (401), and a radial depth (D) of each groove (401) is greater than or equal to 2% of the blade radius of the axial flow fan (100) and less than or equal to 7% of the blade radius of the axial flow fan (100).

9. The air guide ring for an axial flow fan according to claim 8, characterized in that: Each of the grooves (401) has an opening, and an axial height (H) of the opening is greater than or equal to 0.3 mm and less than or equal to 5 mm.

10. The air guide ring for an axial flow fan according to claim 8, characterized in that: The groove portion (104) has three or more grooves (401).

11. The air guide ring for an axial flow fan according to claim 8, characterized in that: The blade tip (107) of the blade (106) of the impeller (110) forms an axial projection line (501) on any cutting surface including the rotation axis (130), the axial projection line (501) is a straight line, and the distance between the axial projection line (501) and the intersection line (503) is equal everywhere; and The position of the groove portion (104) on the inner surface (105) is set so that the axial midpoint of the body (103) is located inside the groove portion (104).

12. The air guide ring for an axial flow fan according to claim 11, characterized in that: The groove portion (104) extends from any axial end of the body (103) and from a position 0.3 times the axial height of the body (103) to a position 0.7 times the axial height of the body (103).

13. The air guide ring for an axial flow fan according to claim 8, characterized in that: The blade tips (107) of the blades (106) of the axial flow fan (100) form an axial projection line (501) on any cutting surface including the rotation axis (130), and the inner surface (105) of the body (103) has a minimum spacing portion (502) closest to the axial projection line (501); and The position of the groove portion (104) on the inner surface (105) is set so that the minimum spacing portion (502) is located within the groove portion (104).

14. The air guide ring for an axial flow fan according to claim 13, characterized in that: The minimum spacing portion (502) is approximately located in the middle of the groove portion (104).

15. The air guide ring for an axial flow fan according to claim 8, characterized in that: The groove portion (104) has a plurality of closed annular grooves (901) or a plurality of turns of spiral grooves (902).

16. An axial flow fan, the axial flow fan (100) comprising an air guide ring (101) and an impeller (110), characterized in that: The air guide ring (101) is the air guide ring (101) for an axial flow fan according to any one of claims 8 to 15.

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