Accelerating efficient mixed flow fan for grain air blowing

Abstract

The invention relates to the technical field of mixed-flow fans, and provides an accelerated efficient mixed-flow fan for grain air blasting, which comprises a barrel body, an impeller, a driving motor and a machine shell group, the barrel body is mounted on the machine shell group, the driving motor is mounted in the machine shell group, the impeller is mounted on a rotating shaft of the driving motor, and the impeller is positioned in the barrel body; eight groups of blades are uniformly distributed on the impeller, flow guide strips are arranged on each group of blades, the flow guide strips comprise large flow guide strips and small flow guide strips, the large flow guide strips are positioned on one sides, far away from the axis of the impeller, of the blades, and the small flow guide strips are positioned on one sides, close to the axis of the impeller, of the blades; compared with the prior art, the oblique conical structure can accelerate airflow and improve the fan pressure, the fan flow and the fan efficiency, the sawtooth-shaped sawtooth grooves in the two ends of the blades can reduce noise generated when the airflow passes through, the flow guide fan blades between the outer barrel and the barrel body can guide the airflow direction, and the influence of the inner wall of the barrel body on the airflow is reduced; and the fan pressure, the fan flow and the fan efficiency are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mixed-flow fans, and in particular to an accelerating and efficient mixed-flow fan for grain blowing. Background Art

[0002] A mixed-flow fan is a fan between an axial-flow fan and a centrifugal fan. Since the wind pressure coefficient of this fan is higher than that of the axial-flow fan and the flow coefficient is larger than that of the centrifugal fan, the mixed-flow fan combining the advantages of the two types of fans has a wide range of application scenarios. For example, in the prior art, the mixed-flow fan is applied to a grain blower to improve the efficiency of the grain blower.

[0003] A grain blower is an environmental protection equipment used for exhaust cooling, hot air circulation and grain transportation in supporting grain machinery and equipment. In recent years, with the continuous improvement of the society's requirements for energy conservation, environmental protection and the production working environment, the performance indicators of grain blowers have also been increasingly improved. However, the current grain blowers generally have problems such as insufficient pressure, low flow rate and low efficiency, and it is difficult to meet the requirements of the society and users. The existing technology needs to be improved. Summary of the Invention

[0004] The purpose of the present invention is to provide an accelerating and efficient mixed-flow fan for grain blowing, aiming to solve the problems of insufficient pressure, low flow rate and low efficiency of the existing mixed-flow fan for grain blowing.

[0005] To achieve the above purpose, the present invention provides an accelerating and efficient mixed-flow fan for grain blowing, which includes a barrel body, an impeller, a driving motor and a casing group. The barrel body is installed on the casing group, the driving motor is installed in the casing group, the impeller is installed on the rotating shaft of the driving motor, and the impeller is located in the barrel body; 8 groups of blades are evenly distributed on the impeller, and a flow guide strip is arranged on each group of blades. The flow guide strip includes a large flow guide strip and a small flow guide strip. The large flow guide strip is located on the side of the blade away from the impeller axis, and the small flow guide strip is located on the side of the blade close to the impeller axis.

[0006] Further, the main body of the impeller is in the shape of a frustum of a cone. The height of the frustum of the cone is H1, and 204 mm ≤ H1 ≤ 207 mm; the included angle between the generatrix of the frustum of the cone and the central axis of the frustum of the cone is ∠1, and 28° ≤ ∠1 ≤ 32°; a top cone is arranged at the front end of the impeller, and the top cone is in the shape of a round cover.

[0007] Furthermore, the blade includes an air inlet surface, a windward surface, and an air outlet surface. The air inlet surface is located at the end of the blade away from the driving motor, the air outlet surface is located at the end close to the driving motor, the windward surface is located between the air inlet surface and the air outlet surface, and the large guide strips and small guide strips are arranged on the windward surface. Sawtooth grooves are provided on both the air inlet surface and the air outlet surface of the blade. The lengths of the two groups of sawtooth grooves are the same, both being L1, where 45 mm ≤ L1 ≤ 48 mm. The sawtooth groove includes a large groove and a small groove, and the large groove and the small groove are arranged alternately. A fillet is provided between the large groove and the small groove. Both the large groove and the small groove are parabolic. The vertical distance from the vertex of the parabola to the air inlet surface or the air outlet surface is the depth of the large groove and the small groove, and the two intersections of the parabola with the air inlet surface or the air outlet surface are the widths of the large groove and the small groove. The ratio of the width L8 of the large groove to the width L9 of the small groove is 5:(3.5 - 4.5), and the ratio of the depth L6 of the large groove to the depth L7 of the small groove is 3.5:(1 - 1.5).

[0008] Furthermore, the side of the blade close to the impeller is defined as the inner side, and the side of the blade close to the cylinder body 2 is defined as the outer side. The air inlet angle on the inner side of the blade is ∠2, where 18° ≤ ∠2 ≤ 20°, and the air outlet angle on the inner side of the blade is ∠3, where 31° ≤ ∠3 ≤ 33°. The air inlet angle on the outer side of the blade is ∠4, where 35° ≤ ∠4 ≤ 36°, and the air outlet angle on the outer side of the blade is ∠5, where 46° ≤ ∠5 ≤ 48°.

[0009] Furthermore, the cylinder body includes an inclined section and an arc section. The inclined section is located close to the impeller, the included angle of the inclined section is ∠6, where 42° ≤ ∠6 ≤ 43°, and the height of the inclined section is H2, where 322 mm ≤ H2 ≤ 324 mm. The radius of the arc section is R1, where 96 mm ≤ R1 ≤ 98 mm, and the height of the arc section is H3, where 52 mm ≤ H3 ≤ 53 mm. A fillet is provided at the intersection of the arc section and the inclined section, and the distance between the center of the fillet and the central axis of the cylinder body is H4, where 216 mm ≤ H4 ≤ 217.5 mm.

[0010] Furthermore, the outer sides of multiple groups of blades are evenly distributed on the side surface of a cone. The generatrix of the cone formed by the outer sides of the blades is parallel to the inclined section, and the distance between them is H6, where 14 mm ≤ H6 ≤ 16 mm.

[0011] Furthermore, the housing group includes an outer cylinder and a motor cylinder. The outer cylinder is fixedly connected to the cylinder body, and a guide fan blade is arranged between the outer cylinder and the motor cylinder. The motor cylinder is used to install the driving motor. The projection of the guide fan blade on the plane perpendicular to the guide blade is arc-shaped, the radius of the arc is R2, where 186 mm ≤ R3 ≤ 189 mm, and the arc length is ⌒1, where 157 mm ≤ ⌒1 ≤ 158 mm.

[0012] Furthermore, the blade is arc-shaped, the rotation direction of the blade is opposite to that of the guide fan blade, the guide fan blade is provided with a wind guiding surface, and two groups of large guide strips are arranged on the wind guiding surface.

[0013] Further, a serrated edge is provided on one side of the flow guiding fan blade close to the impeller. The serrated edge includes an edge section and a center section. The center section is located at the midpoint of the serrated edge. Edge sections are provided on both sides of the center section. The distance between the edge section and the center section is H5, where 6 mm ≤ H5 ≤ 6.5 mm. The distance between the edge section and the edge of the flow guiding fan blade is H7, where 2.5 mm ≤ H7 ≤ 3 mm. Both the center section and the edge section are composed of deep grooves and shallow grooves arranged in an alternating order, and there is a gap between the deep grooves and the shallow grooves. The deep grooves and the shallow grooves are parabolic in shape. The vertical distance from the vertex of the parabola to the serrated edge is the depth of the deep grooves and the shallow grooves, and the two intersection points of the parabola and the serrated edge are the widths of the deep grooves and the shallow grooves. The ratio of the depth L3 of the deep grooves to the depth L2 of the shallow grooves is (7.5 - 8):3, and the ratio of the width L4 of the deep grooves to the width L5 of the shallow grooves is 4.5:(3.5 - 4).

[0014] An accelerating and efficient mixed-flow fan for grain blowing provided by the present invention, compared with the prior art, the inclined conical structure can accelerate the air flow, improve the fan pressure, fan flow rate and fan efficiency. The serrated grooves at both ends of the blade can reduce the noise generated when the air flow passes through. The flow guiding fan blade between the outer cylinder and the cylinder body can guide the air flow direction, reduce the influence of the inner wall of the cylinder body on the air flow, and further improve the fan pressure, fan flow rate and fan efficiency. Description of the Drawings

[0015] Figure 1 is a three-dimensional sectional view of an accelerating and efficient mixed-flow fan for grain blowing according to the present invention; Figure 2 is a half-sectional view of an accelerating and efficient mixed-flow fan for grain blowing according to the present invention; Figure 3 is a sectional view of the impeller part in the present invention; Figure 4 is a sectional view of the casing group in the present invention; Figure 5 is a three-dimensional view of the impeller in the present invention; Figure 6 is a sectional view of the cylinder body in the present invention; Figure 7 is a three-dimensional view of the blade in the present invention; Figure 8 is a developed view of the blade in the present invention; Figure 9 is Figure 8 a partial enlarged view of part A in Figure 10 is a side view of the blade in the present invention; Figure 11 is a three-dimensional view of the flow guiding fan blade in the present invention; Figure 12 is a developed view of the flow guiding fan blade in the present invention; Figure 13 It is a side view of the diversion fan blade in the present invention; Figure 14 It is a performance curve graph of an accelerated and highly efficient mixed-flow fan for grain blowing in the present invention; Figure 15 It is a performance curve graph of the prior art; Figure 16 It is a three-dimensional sectional view of the impeller of the prior art fan.

[0016] Explanation of reference numerals: Among them; 1. Housing group; 10. Outer cylinder; 11. Motor cylinder; 12. Diversion fan blade; 120. Central section; 121. Edge section; 122. Deep groove; 123. Shallow groove; 2. Cylinder body; 20. Inclined section; 21. Arc section; 3. Impeller; 30. Blades; 300. Windward surface; 301. Sawtooth groove; 302. Large diversion strip; 303. Small diversion strip; 304. Inlet surface; 305. Outlet surface; 306. Large groove; 307. Small groove; 31. Apex cone; 4. Driving motor. Detailed implementation manners

[0017] The following further elaborates on the present invention with specific embodiments.

[0018] In the present invention, unless otherwise clearly defined and limited, when terms such as "arranged on", "connected", "linked" appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be directly connected or connected through one or more intermediate media. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. For the direction terms in the present invention, they are used to better explain the characteristics and the relationships between the characteristics. It should be understood that when the placement direction of the present invention changes, the direction of the characteristics and the relationships between the characteristics also correspondingly change. Therefore, the direction terms do not constitute an absolute limitation on the characteristics and the relationships between the characteristics in space, but only play a relative limiting role.

[0019] Such as Figures 1 to 13As shown in the figure, the present invention provides an accelerated and efficient mixed-flow fan for grain blowing, including a cylinder body 2, an impeller 3, a driving motor 4 and a casing group 1. The cylinder body 2 is installed on the casing group 1, the driving motor 4 is installed in the casing group 1, the impeller 3 is installed on the rotating shaft of the driving motor 4, and the impeller 3 is located in the cylinder body 2. Eight groups of blades 30 are evenly distributed on the impeller 3, and a flow guide strip is provided on each group of blades 30. The flow guide strip includes a large flow guide strip 302 and a small flow guide strip 303. The large flow guide strip 302 is located on the side of the blade 30 away from the axis of the impeller 3, and the small flow guide strip 303 is located on the side of the blade 30 close to the axis of the impeller 3.

[0020] Through the above design scheme, the large flow guide strip 302 and the small flow guide strip 303 on the blade 30 can guide the air flow to flow along a specific path, reduce the loss caused by the separation of the air flow on the blade 30, and at the same time, the large flow guide strip 302 and the small flow guide strip 303 can also increase the air intake of the blade 30, further improving the efficiency of the fan.

[0021] In this embodiment, the main body of the impeller 3 is in the shape of a frustum of a cone. The height of the frustum of the cone is H1, and 204 mm ≤ H1 ≤ 207 mm; the included angle between the generatrix of the frustum of the cone and the central axis of the frustum of the cone is ∠1, and 28° ≤ ∠1 ≤ 32°.

[0022] In this embodiment, a top cone 31 is provided at the front end of the impeller 3, and the top cone 31 is in the shape of a round cover.

[0023] Through the above design scheme, the top cone 31 can guide the air flow to enter the impeller 3 evenly, reduce the loss of kinetic energy. The round cover-shaped top cone 31 can flatten the path of the fluid, reduce eddy currents and impacts, thereby optimizing the efficiency of the fluid, and at the same time, it can also reduce the noise generated by the air flow impact. Preferably, the height H1 of the frustum of the cone is 205 mm, and the included angle ∠1 between the generatrix of the frustum of the cone and the central axis of the frustum of the cone is 30°.

[0024] In this embodiment, the blade 30 includes an air inlet surface 304, a windward surface 300, and an air outlet surface 305. The air inlet surface 304 is located at one end of the blade 30 away from the drive motor 4, the air outlet surface 305 is located at one end close to the drive motor 4, and the windward surface 300 is located between the air inlet surface 304 and the air outlet surface 305. The large flow guide strip 302 and the small flow guide strip 303 are arranged on the windward surface 300; serrated grooves 301 are arranged on both the air inlet surface 304 and the air outlet surface 305 of the blade 30. The lengths of the two groups of serrated grooves 301 are the same and are both L1, where 45 mm ≤ L1 ≤ 48 mm; the serrated groove 301 includes a large groove 306 and a small groove 307, and the large groove 306 and the small groove 307 are arranged alternately. A fillet is provided between the large groove 306 and the small groove 307; both the large groove 306 and the small groove 307 are parabolic. The vertical distance from the vertex of the parabola to the air inlet surface 304 or the air outlet surface 305 is the depth of the large groove 306 and the small groove 307, and the two intersection points of the parabola and the air inlet surface 304 or the air outlet surface 305 are the widths of the large groove 306 and the small groove 307. The ratio of the width L8 of the large groove 306 to the width L9 of the small groove 307 is 5:(3.5 - 4.5), and the ratio of the depth L6 of the large groove 306 to the depth L7 of the small groove 307 is 3.5:(1 - 1.5).

[0025] Through the above design, the serrated grooves 301 on the air inlet surface 304 and the air outlet surface 305 of the blade 30 can absorb the noise generated by the rotation of the blade 30. The alternately distributed large grooves 306 and small grooves 307 can filter large air vortices into fine small vortices, suppressing the generation of turbulent boundary noise; preferably, the length L1 of the serrated groove 301 is 45.8 mm, and there are 10 large grooves 306 and 9 small grooves 307 in the serrated groove 301.

[0026] In this embodiment, the side of the blade 30 close to the impeller 3 is defined as the inner side, and the side of the blade 30 close to the cylinder body 2 is defined as the outer side. The air inlet angle on the inner side of the blade 30 is ∠2, where 18° ≤ ∠2 ≤ 20°, and the air outlet angle on the inner side of the blade 30 is ∠3, where 31° ≤ ∠3 ≤ 33°; the air inlet angle on the outer side of the blade 30 is ∠4, where 35° ≤ ∠4 ≤ 36°, and the air outlet angle on the outer side of the blade 30 is ∠5, where 46° ≤ ∠5 ≤ 48°.

[0027] In this embodiment, the cylinder body 2 is intercepted by a plane passing through the central axis of the cylinder body 2. On the cross-section, the cylinder body 2 includes an inclined section 20 close to the housing group 1 and an arc section 21 far from the housing group 1; the included angle of the inclined section 20 is ∠6, 42° ≤ ∠6 ≤ 43°, the height of the inclined section 20 is H2, 322 mm ≤ H2 ≤ 324 mm; the radius of the arc section 21 is R1, 96 mm ≤ R1 ≤ 98 mm, the height of the arc section 21 is H3, 52 mm ≤ H3 ≤ 53 mm; a fillet is provided at the intersection of the arc section 21 and the inclined section 20, and the distance between the center of the fillet and the central axis of the cylinder body 2 is H4, 216 mm ≤ H4 ≤ 217.5 mm.

[0028] Through the above design, the impeller 3 guides the air flow to enter from the gradually narrowing arc section 21 and then flow into the gradually increasing inclined section 20. After the air flow path is reduced and then enlarged, its flow rate will increase, and the fan efficiency is improved by changing the air flow rate. Preferably, the included angle ∠6 of the inclined section 20 is 42.58°, and the height H2 of the inclined section 20 is 322 mm; the arc radius R1 of the arc section 21 is 97 mm, and the height H3 of the arc section 21 is 53 mm.

[0029] In this embodiment, the outer sides of multiple groups of blades 30 are evenly distributed on the side surface of a cone. The cone generatrix formed by the outer sides of the blades 30 is parallel to the inclined section 20, and the distance between them is H6, 14 mm ≤ H6 ≤ 16 mm.

[0030] In this embodiment, the housing group 1 includes an outer cylinder 10 and a motor cylinder 11. The outer cylinder 10 is fixedly connected to the cylinder body 2, and a guide fan blade 12 is arranged between the outer cylinder 10 and the motor cylinder 11. The motor cylinder 11 is used to install the driving motor 4; the projection of the guide fan blade 12 on the plane perpendicular to the guide blade 12 is arc-shaped, the radius of the arc is R2, 186 mm ≤ R2 ≤ 189 mm, and the arc length is ⌒1, 157 mm ≤ ⌒1 ≤ 158 mm.

[0031] In this embodiment, the blade 30 is arc-shaped, the rotation direction of the blade 30 is opposite to that of the guide fan blade 12, the guide fan blade 12 is provided with a wind guiding surface, and two groups of large guiding strips 302 are arranged on the wind guiding surface.

[0032] Through the above design, the large guiding strips 302 on the guide fan blade 12 can comb the air flow output by the impeller 3, divide the large-area air flow into small-area air flows, and further guide the air flow to pass smoothly, so as to reduce the loss of air flow kinetic energy; the guide fan blade 12 opposite to the opening of the blade 30 can change the axial air flow generated by the rotation of the blade 30 into a radial air flow, and make the air flow smoother by changing the air flow direction.

[0033] In this embodiment, a serrated edge is provided on the side of the guide fan blade 12 close to the impeller 3. The serrated edge includes an edge section 121 and a central section 120. The central section 120 is located at the middle position of the serrated edge. Edge sections 121 are provided on both sides of the central section 120. The distance between the edge section 121 and the central section 120 is H5, where 6 mm ≤ H5 ≤ 6.5 mm. The distance between the outermost edge of the edge section 121 and the edge of the guide fan blade 12 is H7, where 2.5 mm ≤ H7 ≤ 3 mm. Both the central section 120 and the edge section 121 are composed of deep grooves 122 and shallow grooves 123 arranged in an alternating order, and there is a gap between the deep grooves 122 and the shallow grooves 123. Both the deep grooves 122 and the shallow grooves 123 are parabolic. The vertical distance from the vertex of the parabola to the serrated edge is the depth of the deep grooves 122 and the shallow grooves 123, and the two intersection points of the parabola and the serrated edge are the widths of the deep grooves 122 and the shallow grooves 123. The ratio of the depth L3 of the deep grooves 122 to the depth L2 of the shallow grooves 123 is (7.5 - 8):3, and the ratio of the width L4 of the deep grooves 122 to the width L5 of the shallow grooves 123 is 4.5:(3.5 - 4).

[0034] To verify this embodiment, a blower impeller as shown in Figure 16 is used as a comparative example, and the impeller diameter is 620 mm. Meanwhile, based on the preferred structural parameters provided in this embodiment, a high-speed and efficient mixed-flow blower for grain air-blowing is manufactured with the diameter of the impeller 3 (i.e., the outer peripheral circle diameter formed by the outermost ends of multiple blades) being 620 mm as a test example. By Figure 16 comparing the existing blower impeller shown in with this embodiment, it can be seen that for the existing blower impeller, in this embodiment, a serrated groove 301 is provided on the blade 30 of the impeller 3. The serrated groove 301 can change the noise generated when cutting the air flow. At the same time, large guide strips 302 and small guide strips 303 are also provided on the blade in this embodiment. The large guide strips 302 and the small guide strips 303 can divide and guide the air flow, and can also further increase the air intake volume, enabling this embodiment to obtain a higher air intake effect.

[0035] Performance tests are carried out on the comparative example and the test example, and the test results are converted into test data under the test conditions of an atmospheric pressure of 101325 Pa, an atmospheric temperature of 20 °C, a blower speed of 1450 r / min, and a medium density of 1.2 kg / m 3 The test example obtains the test data shown in Table 1 and Figure 14 the performance curve shown in, and the comparative example obtains the test data shown in Table 2 and Figure 15 the performance curve shown in. The performance curve takes the volume flow rate as the abscissa. In the performance curve, qvsglGu is the volume flow rate, LAGu is the A-weighted sound level, ηr is the blower efficiency, PrGu is the impeller power, pFGu is the total pressure, and psFGu is the static pressure.

[0036] Performance Test Report of the Accelerated and High-Efficiency Mixed-Flow Fan for Grain Blowing

[0037] Performance Test Report of the Existing Mixed-Flow Fan

[0038] It can be seen from the test data and performance curves that, compared with the comparative example, the comparative example is inferior to the test example in terms of volume flow rate, fan efficiency, and A-weighted sound level. For the comparative example, the maximum volume flow rate is 11985 m 3 / h, the highest point of the fan efficiency is 39.806%, and the maximum value of the fan static pressure is 552.66 Pa. For the test example, the maximum volume flow rate is 14762 m 3 / h, the highest point of the fan efficiency is 41.915%, and the maximum value of the fan static pressure is 618.55 Pa. Specifically, in the comparative example, when the static pressure is 552.66 Pa, the volume flow rate is 3446.6 m 3 / h, and the fan efficiency is 32.450%; in the test example, when the static pressure is 551.27 Pa, the volume flow rate is 8207.4 m 3 / h, and the fan efficiency is 41.270%. In comparison, the fan of the test example has a larger volume flow rate, higher fan efficiency, and higher static pressure.

[0039] The accelerated and high-efficiency mixed-flow fan for grain blowing provided by the present invention, compared with the prior art, the inclined conical structure can accelerate the airflow, improve the fan pressure, fan flow rate, and fan efficiency. The serrated grooves 301 at both ends of the blade 30 can reduce the noise generated when the airflow passes through. The guide fan blades 12 between the outer cylinder 10 and the cylinder body 2 can guide the airflow direction, reduce the influence of the inner wall of the cylinder body 2 on the airflow, and further improve the fan pressure, fan flow rate, and fan efficiency.

[0040] Without conflict, the above-mentioned embodiments and the features in the embodiments can be combined with each other.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An accelerating high-efficiency mixed flow fan for grain blowing, characterized in that: The invention comprises a barrel (2), an impeller (3), a drive motor (4) and a casing group (1), wherein the barrel (2) is mounted on the casing group (1), the drive motor (4) is mounted in the casing group (1), the impeller (3) is mounted on the rotating shaft of the drive motor (4), and the impeller (3) is located in the barrel (2); 8 groups of blades (30) are evenly distributed on the impeller (3), each group of blades (30) is provided with a guide bar, the guide bar comprises a large guide bar (302) and a small guide bar (303), the large guide bar (302) is located on a side of the blade (30) away from the axis of the impeller (3), and the small guide bar (303) is located on a side of the blade (30) close to the axis of the impeller (3).

2. The high-efficiency mixed flow fan for grain blowing according to claim 1, characterized in that: The main body of the impeller (3) is in the shape of a truncated cone, the height of the truncated cone is H1, 204 mm ≤ H1 ≤ 207 mm; the angle between the generatrix of the truncated cone and the center axis of the truncated cone is ∠1, 28° ≤ ∠1 ≤ 32°; a top cone (31) is provided at the front end of the impeller (3), and the top cone (31) is in the shape of a round cap.

3. The high-efficiency mixed flow fan for grain blowing according to claim 1, characterized in that: The blade (30) comprises an air inlet surface (304), a windward surface (300) and an air outlet surface (305); the air inlet surface (304) is located at an end of the blade (30) away from the drive motor (4); the air outlet surface (305) is located at an end close to the drive motor (4); the windward surface (300) is located between the air inlet surface (304) and the air outlet surface (305); a large guide strip (302) and a small guide strip (303) are arranged on the windward surface (300); sawtooth grooves (301) are arranged on the air inlet surface (304) and the air outlet surface (305) of the blade (30); the lengths of the two groups of sawtooth grooves (301) are the same and are both L1, 45 mm≤L1≤48 mm; the sawtooth grooves (301) comprise large grooves (306) and small grooves (307) The large grooves (306) and the small grooves (307) are arranged in an alternating manner, and a chamfered corner is provided between the large grooves (306) and the small grooves (307); the large grooves (306) and the small grooves (307) are both parabolic in shape, the vertical distance between the vertex of the parabola and the air inlet surface (304) or the air outlet surface (305) is the depth of the large grooves (306) and the small grooves (307), the two intersection points of the parabola and the air inlet surface (304) or the air outlet surface (305) are the widths of the large grooves (306) and the small grooves (307), the ratio of the width L8 of the large grooves (306) to the width L9 of the small grooves (307) is 5:(3.5-4.5), and the ratio of the depth L6 of the large grooves (306) to the depth L7 of the small grooves (307) is 3.5:(1-1.5).

4. The high-efficiency mixed flow fan for grain blowing according to claim 3, characterized in that: The side of the blade (30) close to the impeller (3) is defined as the inner side, and the side of the blade (30) close to the barrel (2) is defined as the outer side. The air inlet angle of the inner side of the blade (30) is ∠2, 18°≤∠2≤20°, and the air outlet angle of the inner side of the blade (30) is ∠3, 31°≤∠3≤33°; the air inlet angle of the outer side of the blade (30) is ∠4, 35°≤∠4≤36°, and the air outlet angle of the outer side of the blade (30) is ∠5, 46°≤∠5≤48°.

5. The high-efficiency mixed flow fan for grain blowing according to claim 1, characterized in that: The barrel (2) is cut with a plane passing through the central axis of the barrel (2). In the cross section, the barrel (2) comprises an inclined section (20) close to the housing assembly (1) and an arc section (21) away from the housing assembly (1); the angle of the inclined section (20) is ∠6, 42°≤∠6≤43°, the height of the inclined section (20) is H2, 322mm≤H2≤324mm; the radius of the arc section (21) is R1, 96mm≤R1≤98mm, the height of the arc section (21) is H3, 52mm≤H3≤53mm; a chamfer is provided at the intersection of the arc section (21) and the inclined section (20), the distance between the center of the chamfer and the central axis of the barrel (2) is H4, 216mm≤H4≤217.5mm.

6. The high-efficiency mixed flow fan for grain blowing according to claim 1, characterized in that: The outer sides of the plurality of blades (30) are evenly distributed on a group of conical side surfaces, and the conical generatrix formed on the outer sides of the blades (30) is parallel to the inclined section (20), and the spacing between the two is H6, 14 mm ≤ H6 ≤ 16 mm.

7. The high-efficiency mixed flow fan for grain blowing according to claim 1, characterized in that: The casing assembly (1) comprises an outer cylinder (10) and a motor cylinder (11); the outer cylinder (10) is fixedly connected to the cylinder body (2); a guide blade (12) is arranged between the outer cylinder (10) and the motor cylinder (11); the motor cylinder (11) is used to install a drive motor (4); the projection of the guide blade (12) on a plane perpendicular to the guide blade (12) is in the shape of an arc; the radius of the arc is R2, 186 mm ≤ R2 ≤ 189 mm; the arc length is ⌒1, 157 mm ≤ ⌒1 ≤ 158 mm.

8. The high-efficiency mixed flow fan for grain blowing according to claim 7, characterized in that: The blade (30) is in an arc shape, and the rotation direction of the blade (30) is opposite to that of the guide blade (12). The guide blade (12) is provided with an air guide surface, and two groups of large guide strips (302) are provided on the air guide surface.

9. The high-efficiency mixed flow fan for grain blowing according to claim 8, characterized in that: A serrated edge is provided on a side of the guide blade (12) close to the impeller (3), the serrated edge comprising an edge segment (121) and a center segment (120), the center segment (120) being located in the middle of the serrated edge, edge segments (121) being provided on both sides of the center segment (120), the spacing between the outermost edge of the edge segment (121) and the center segment (120) being H5, 6mm≤H5≤6.5mm, and the spacing between the edge segment (121) and the edge of the guide blade (12) being H7, 2.5mm≤H7≤3mm; the center segment (120) and the edge segment (121) are both formed by staggered deep grooves (122 ) and a shallow groove (123), a gap is provided between the deep groove (122) and the shallow groove (123); the deep groove (122) and the shallow groove (123) are both parabolic, the vertical distance between the vertex of the parabola and the sawtooth edge is the depth of the deep groove (122) and the shallow groove (123), the two intersection points of the parabola and the sawtooth edge are the widths of the deep groove (122) and the shallow groove (123), the ratio of the depth L3 of the deep groove (122) to the depth L2 of the shallow groove (123) is (7.5-8):3, and the ratio of the width L4 of the deep groove (122) to the width L5 of the shallow groove (123) is 4.5:(3.5-4).

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