Cross-flow fan volute
By using a logarithmic spiral line volute design in the flow fan to control the eccentric vortex, the problems of large airflow resistance and low efficiency in the existing fan design are solved, and more efficient airflow flow and reduced vibration noise are achieved.
Patent Information
- Application Number
- CN202421078614.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2034-05-17
AI Technical Summary
In the existing cross-flow fan design, the formation of an eccentric vortex causes the airflow flow direction to change, affect the fan efficiency, and the design depends on tests, resulting in high R&D costs and long cycles.
The logarithmic spiral line of the left volute and the right volute is used to combine the specific initial radius and the air flow incident angle. By defining the volute, the volute tongue parameters and the assembly relationship with the impeller, a fan volute with a special structure is manufactured to control the eccentric vortex, form a flow and reduce the air flow resistance.
Effectively reduce the backflow of the bottom of the worm tongue, improve the fan efficiency, and reduce the fan vibration and noise.
Smart Images
Figure CN222576971U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of fan volutes, in particular to a crossflow fan volute. Background Art
[0002] A cross-flow fan is a common ventilation equipment, and its structure mainly includes an impeller, a volute and a volute tongue. During the operation of the fan, the gas flows in radially and finally flows out radially, passing through the fan blades twice. The generated airflow has the characteristics of large flow and lateral uniformity. Regardless of the diameter of the impeller, the impeller length can be freely selected according to the requirements of the air volume. Therefore, it is widely used in various energy utilization systems such as refrigeration and air conditioning, chemical machinery, etc.
[0003] The gas in the crossflow fan enters and exits through the blades. When passing through the blades for the first time, the blades do work on the airflow, reducing the flow velocity and increasing the static pressure. When passing through the blades for the second time, the flow velocity increases relatively and the static pressure decreases, causing the static pressure inside the impeller to change. The change in the pressure gradient inside the impeller and the influence of the impeller movement cause part of the fluid to flow back at the lowest point of static pressure, which is the vortex phenomenon also called eccentric vortex. The eccentric vortex will change the direction of the airflow and affect the efficiency of the crossflow fan.
[0004] The formation of eccentric vortex is closely related to the shape and relative position of volute and volute tongue, but its cause is very complex and its state is uncertain, which limits people's research on cross-flow fans. The current design is mainly based on experimental testing and experience methods, which requires a large number of experiments, resulting in high R&D costs and long R&D cycles, which brings troubles to the application of cross-flow fans in refrigeration products. Utility Model Content
[0005] The utility model aims to provide a volute of a crossflow fan, which can reduce the resistance of airflow, reduce the backflow at the bottom of the volute tongue, improve the efficiency of the fan, and at the same time reduce the vibration and noise of the fan.
[0006] The utility model includes a fan casing, which is an upwardly opening cavity surrounded by a left plate, a right plate and a volute, and an impeller is installed in the cavity; the space between the left plate and the right plate constitutes an air inlet of the fan, and an air inlet is arranged above the air inlet; the volute includes a left volute and a right volute, the lower part of the left plate is connected to the left volute, the left volute is connected to the lower side plate, the lower part of the right plate is connected to the right volute, and the right volute is connected to the volute tongue and the upper side plate in sequence; the upper side plate and the lower side plate jointly form an air outlet on the lower right side of the fan casing, and an air outlet is arranged at the end of the air outlet; the profile of the left volute and the right volute is a logarithmic spiral, the initial radius of the profile is R2, the outlet airflow angle is α, and the polar angle is m is a multiple of the polar angle φ, and the equation of the logarithmic spiral is: x = R2·e m·tanα cosφ,y=R2·e m·tanα sinφ.
[0007] Preferably, the left side plate is formed by three straight plates, namely, a left upper plate, a left middle plate and a left lower plate, which are connected end to end in sequence. The left middle plate is arranged in a vertical direction, and the left upper plate is inclined to the left with the upper end of the left middle plate as the starting point, forming an angled inlet flare on the left side of the air inlet.
[0008] Preferably, the angle between the line connecting the lower end point of the left lower plate and the center point of the impeller and the horizontal direction is not less than 0 degrees and not more than 10 degrees.
[0009] Preferably, the angle between the line connecting the intersection of the left lower plate and the left middle plate and the center point of the impeller and the line connecting the lower end point of the left lower plate and the center point of the impeller is not less than 10 degrees and not more than 35 degrees.
[0010] Preferably, the left volute profile starts from the lower end of the left lower plate, gradually expands in the counterclockwise direction, and its end point is tangent to the lower side plate; the initial radius of the left volute R2 = r + c1, r is the impeller radius, c1 is the radius characteristic constant of the left volute, and the value of c1 is not less than 3.5 mm and not more than 7.5 mm; the outlet airflow angle α1 of the left volute ranges from 11 degrees to 13 degrees, and the value range of m is not less than 1 times the polar angle φ, and not more than 1.02 times the polar angle φ.
[0011] Preferably, the right side plate is formed by connecting two straight plates, a right upper plate and a right middle plate. The right middle plate is arranged in a vertical direction, and the right upper plate is inclined to the right with the end of the right middle plate as the starting point, forming an inlet expansion with an oblique angle on the right side of the air inlet.
[0012] Preferably, the right volute profile starts from the lower end of the right middle plate, gradually expands in a clockwise direction, and its end point is tangent to the volute tongue; the initial radius of the right volute R2=r+c2, r is the impeller radius, c2 is the gap between the volute tongue and the impeller, and the value of c2 is not less than 3mm and not more than 6mm; the outlet airflow angle α2 of the right volute ranges from 4 degrees to 6 degrees, and the value range of m is not less than 1 times the polar angle φ, and not more than 1.02 times the polar angle φ.
[0013] Preferably, the volute tongue is in an arc shape, and the radius r1 of the volute tongue is not less than 2 mm and not more than 6 mm; the angle between the line connecting the center of the volute tongue and the center of the impeller and the horizontal direction is not less than 25 degrees and not more than 35 degrees, and the length of the line connecting the center of the volute tongue and the center of the impeller is L=r+r1+c3, r is the impeller radius, c3 is a constant, and the value of c3 is not less than 2 mm and not more than 7 mm.
[0014] Preferably, the lower side plate and the upper side plate are arranged in a horizontal direction.
[0015] Preferably, an assembly gap of 2-5 mm is left on the outer sides of the left plate and the right plate respectively.
[0016] In summary, the utility model has the following beneficial effects:
[0017] 1. The profiles of the left and right volutes are logarithmic spirals, and the two share a set of logarithmic spiral equations. The involute opening direction of the left volute is consistent with the impeller direction, and the involute opening direction of the right volute is opposite to the impeller direction. The left and right volutes respectively adopt specific initial radius values and airflow incident angle values. By adopting the logarithmic spiral curve provided by the utility model, by limiting the parameters of the volute, the volute tongue and the assembly relationship between the volute and the impeller, a fan volute with a special structure is manufactured, which can control the eccentric vortex, form a throughflow, and achieve the effect of reducing airflow resistance;
[0018] 2. The volute tongue is in an arc shape. By setting the radius of the volute tongue, the position of the center of the volute tongue, and the distance between the center of the volute tongue and the impeller, the backflow at the bottom of the volute tongue can be effectively reduced, which helps to improve the efficiency of the fan and also helps to reduce the noise of the fan;
[0019] 3. There are outward expansions on the left and right sides of the air inlet to guide the airflow, reduce airflow resistance and intake noise; there is a 2-5mm assembly gap between the end of the air inlet and the inner tank and the fan panel, and the gap is filled with foam glue to avoid direct contact between the air duct and the inner tank and the air outlet panel, which is beneficial to reduce vibration noise. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a schematic diagram of the overall structure of a volute of a crossflow fan of the utility model;
[0021] Figure 2 It is a cross-sectional view of a volute of a cross-flow fan of the utility model;
[0022] Figure 3 for Figure 2 A partial enlarged view of
[0023] Figure 4 It is a curve diagram of the volute profile.
[0024] In the figure: 1. fan casing; 2. left side panel; 201. upper left panel; 202. left middle panel; 203. lower left panel; 3. right side panel; 301. upper right panel; 302. right middle panel; 5. impeller; 6. air inlet; 7. air inlet; 8. left volute; 9. right volute; 10. air outlet; 11. air outlet; 12. lower side panel; 13. upper side panel; 14. volute tongue; 15. liner; 16. air outlet panel. DETAILED DESCRIPTION
[0025] The utility model will be further described below in conjunction with the accompanying drawings.
[0026] The orientations mentioned in this specification are based on the orientations of the volute of a cross-flow fan of the utility model when it is working normally, and do not limit the orientations during storage and transportation. They only represent relative positional relationships, not absolute positional relationships.
[0027] like Figures 1 to 4 As shown together, a crossflow fan volute includes a fan housing 1, the left side of the fan housing 1 is an inner tank 15, and the right side of the fan housing 1 is an air outlet panel 16; the fan housing 1 is a cavity with an opening upward formed by a left side plate 2, a right side plate 3 and a volute, and an impeller 5 is installed in the cavity; the space between the left side plate 2 and the right side plate 3 constitutes an air inlet 6 of the fan, and an air inlet 7 is provided above the air inlet 6; the volute includes a left volute 8 and a right volute 9, the lower part of the left side plate 2 is connected to the left volute 8, and the left volute 8 is connected to the lower side plate 12 (i.e. Figure 2 The lower part of the right side plate 3 is connected to the right side volute 9, and the right side volute 9 is connected to the volute tongue 14 and the upper side plate 13 (i.e. Figure 2 The upper side plate 13 and the lower side plate 12 together form an air outlet 10 on the lower right side of the fan housing 1, and the upper side plate 13 and the lower side plate 12 are horizontally arranged on the upper and lower sides of the air outlet 10, and an air outlet 11 is provided at the end of the air outlet 10.
[0028] Furthermore, the left side plate 2 is formed by connecting three straight plates, the left upper plate 201, the left middle plate 202 and the left lower plate 203, end to end in sequence (i.e., corresponding to Figure 2 AB, BC and CD segments in the left middle plate 202, the left middle plate 202 is arranged in a vertical direction, and the left upper plate 201 takes the upper end of the left middle plate 202 as the starting point (i.e. Figure 2 The left side of the air inlet 7 is inclined to the left, and an inlet expansion with an oblique angle is formed on the left side of the air inlet 7. The end of the left upper plate 201 (i.e. Figure 2 There is a 2-5mm assembly gap between the vertical extension line of the left lower plate 203 and the inner tank 15, and the gap is filled with foam glue to prevent the air duct from directly contacting the inner tank 15; the line connecting the lower end point of the left lower plate 203 and the center point of the impeller 5 (i.e. Figure 2 O1D in the horizontal direction (i.e. Figure 2 The negative direction of the x-axis in Figure 3 The φ1 angle in the figure is not less than 0 degrees and not greater than 10 degrees; the line connecting the intersection of the left lower plate 203 and the left middle plate 202 and the center point of the impeller 5 (i.e. Figure 2 O1C in the figure) and the line connecting the lower end point of the left lower plate (203) and the center point of the impeller (5) (i.e. Figure 2 The angle between O1D and Figure 3 The φ2 angle in the image is not less than 10 degrees and not greater than 35 degrees;
[0029] Furthermore, the right side plate 3 is formed by connecting two straight plates, the right upper plate 301 and the right middle plate 302 (i.e., corresponding to Figure 2 The right middle plate 302 is arranged in a vertical direction, and the right upper plate 301 is at the end of the right middle plate 302 (i.e. Figure 2 The K point in the figure is the starting point and tilts to the right, forming an inlet expansion with an oblique angle on the right side of the air inlet 7. The end of the right upper plate 301 (i.e. Figure 2 A 2-5 mm assembly gap is left between the vertical extension line of the air outlet panel 16 (point L in the figure), and the gap is filled with foam glue to prevent the air duct from directly contacting the air outlet panel 16.
[0030] The profiles of the left volute 8 and the right volute 9 are logarithmic spirals, and both share a set of logarithmic spiral equations, which are: x = R2·e m·tanα cosφ,y=R2·e m·tanα sinφ, the initial radius of the volute profile is R2, the airflow angle at the blade outlet is α, the polar angle is φ, and m is a multiple of the polar angle φ. The value range of m for the left volute 8 and the right volute 9 is not less than 1 times the polar angle φ and not more than 1.02 times the polar angle φ; the curve is as follows Figure 4 As shown in the figure, R is the radius of the logarithmic spiral at any angle φ, the radius of the volute at φ=0 is the initial radius R2, R2=r+c, r is the fan radius, c is the radius characteristic constant, and in the volute, it specifically refers to the gap between the volute and the fan. The left volute 8 and the right volute 9 correspond to different outlet airflow angles α and radius characteristic constants c, respectively.
[0031] The left volute 8-shaped line is at the lower end of the left lower plate 203 (i.e. Figure 2 The starting point is point D in the figure, and it gradually expands in the counterclockwise direction, which is consistent with the rotation direction of the fan. Figure 2 The left volute 8 has an initial radius R2=r+c1, where r is the radius of the impeller 5, c1 is the characteristic radius constant of the left volute 8, and the value of c1 is not less than 3.5 mm and not more than 7.5 mm; the outlet airflow angle α1 of the left volute 8 ranges from 11 degrees to 13 degrees.
[0032] Among them, the right side volute 9 line (i.e. Figure 2 The lower end of the right middle plate 302 (i.e. Figure 2 The right volute 9 takes point J in the figure as the starting point, gradually expands in the clockwise direction, which is opposite to the rotation direction of the fan, and its end point is tangent to the volute tongue 14; the initial radius R2=r+c2 of the right volute 9, r is the radius of the impeller 5, c2 is the gap between the volute tongue 14 and the impeller 5, and the value of c2 is not less than 3mm and not more than 6mm; the outlet airflow angle α2 of the right volute 9 ranges from 4 degrees to 6 degrees.
[0033] Furthermore, the volute tongue 14 is in the shape of an arc (its center is Figure 2 The radius r1 of the volute tongue 14 is not less than 2 mm and not more than 6 mm. The starting point of the volute tongue 14 (i.e. Figure 2 Point I in the figure) is tangent to the lower end of the right volute 9; the line connecting the center of the volute tongue 14 and the center of the impeller 5 (i.e. Figure 2 The angle between O1O2) and the horizontal direction (i.e. Figure 3 The φ3 angle in the figure is not less than 25 degrees and not more than 35 degrees, and the length of the line connecting the center of the volute tongue 14 and the center of the impeller 5 (i.e. Figure 2 In the O1O2 section) L=r+r1+c3, r is the radius of the impeller 5, c3 is a constant, and the value of c3 is not less than 2 mm and not more than 7 mm.
[0034] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.
Claims
1. A volute of a crossflow fan, characterized in that: The invention comprises a fan casing (1), wherein the fan casing (1) is a cavity opened upward and surrounded by a left side plate (2), a right side plate (3) and a volute, wherein an impeller (5) is installed in the cavity; the space between the left side plate (2) and the right side plate (3) constitutes an air inlet (6) of the fan, and an air inlet (7) is arranged above the air inlet (6); the volute comprises a left volute (8) and a right volute (9), wherein the lower part of the left side plate (2) is connected to the left volute (8), the left volute (8) is connected to the lower side plate (12), and the right side plate (13) is connected to the lower side plate (14). The lower part of the plate (3) is connected to the right volute (9), and the right volute (9) is connected to the volute tongue (14) and the upper side plate (13) in sequence; the upper side plate (13) and the lower side plate (12) together form an air outlet duct (10) on the lower right side of the fan housing (1), and an air outlet (11) is provided at the end of the air outlet duct (10); the profile of the left volute (8) and the right volute (9) is a logarithmic spiral, the initial radius of the logarithmic spiral is R2, the outlet airflow angle is α, m is a multiple of the polar angle φ, and the equation of the logarithmic spiral is: x=R2·e m·tanα cosφ,y=R2·e m·tanα sinφ.
2. A crossflow fan volute according to claim 1, characterized in that: The left side plate (2) is formed by connecting three straight plates, namely a left upper plate (201), a left middle plate (202) and a left lower plate (203), end to end in sequence; the left middle plate (202) is arranged in a vertical direction; the left upper plate (201) is inclined to the left with the upper end of the left middle plate (202) as a starting point, forming an inlet flare with an oblique angle on the left side of the air inlet (7).
3. A crossflow fan volute as claimed in claim 2, characterized in that: The angle between the line connecting the lower end point of the left lower plate (203) and the center point of the impeller (5) and the horizontal direction is not less than 0 degrees and not more than 10 degrees.
4. A crossflow fan volute as claimed in claim 2, characterized in that: The angle between the line connecting the intersection of the left lower plate (203) and the left middle plate (202) and the center point of the impeller (5) and the line connecting the lower end point of the left lower plate (203) and the center point of the impeller (5) is not less than 10 degrees and not more than 35 degrees.
5. A crossflow fan volute as claimed in claim 2, characterized in that: The left volute (8) profile starts from the lower end of the left lower plate (203), gradually expands in the counterclockwise direction, and its end point is tangent to the lower side plate (12); the initial radius R2 of the left volute (8) is r+c1, r is the radius of the impeller (5), c1 is the radius characteristic constant of the left volute (8), and the value of c1 is not less than 3.5 mm and not more than 7.5 mm; the outlet airflow angle α1 of the left volute (8) ranges from 11 degrees to 13 degrees, and the value range of m is not less than 1 times the polar angle φ and not more than 1.02 times the polar angle φ.
6. A crossflow fan volute as claimed in claim 1, characterized in that: The right side plate (3) is formed by connecting two straight plates, a right upper plate (301) and a right middle plate (302); the right middle plate (302) is arranged in a vertical direction; the right upper plate (301) is inclined to the right with the end of the right middle plate (302) as a starting point, forming an inlet flare with an oblique angle on the right side of the air inlet (7).
7. A crossflow fan volute as claimed in claim 6, characterized in that: The right volute (9) profile starts from the lower end of the right middle plate (302), gradually expands in a clockwise direction, and its end point is tangent to the volute tongue (14); the initial radius R2 of the right volute (9) is r+c2, r is the radius of the impeller (5), c2 is the gap between the volute tongue (14) and the impeller (5), and the value of c2 is not less than 3 mm and not more than 6 mm; the outlet airflow angle α2 of the right volute (9) ranges from 4 degrees to 6 degrees, and the value range of m is not less than 1 times the polar angle φ, and not more than 1.02 times the polar angle φ.
8. A crossflow fan volute as claimed in claim 1, characterized in that: The volute tongue (14) is in an arc shape, and the radius r1 of the volute tongue (14) is not less than 2 mm and not more than 6 mm; the angle between the line connecting the center of the volute tongue (14) and the center of the impeller (5) and the horizontal direction is not less than 25 degrees and not more than 35 degrees, and the length L of the line connecting the center of the volute tongue (14) and the center of the impeller (5) is r+r1+c3, r is the radius of the impeller (5), c3 is a constant, and the value of c3 is not less than 2 mm and not more than 7 mm.
9. A crossflow fan volute as claimed in claim 1, characterized in that: The lower side plate (12) and the upper side plate (13) are arranged in a horizontal direction.
10. A volute of a crossflow fan according to claim 1, characterized in that: An assembly gap of 2-5 mm is respectively reserved on the outer sides of the left side plate (2) and the right side plate (3).