Centrifugal fan wheel

Abstract

The application provides a centrifugal wind wheel, and belongs to the technical field of fan manufacturing. The centrifugal wind wheel solves the problems of small air volume and small static pressure of the existing centrifugal wind wheel. The centrifugal wind wheel comprises a front disc, a rear disc and a plurality of blades, the blades are circumferentially and uniformly fixed between the front disc and the rear disc, an air outlet is arranged between the front disc and the rear disc, the middle part of the front disc is provided with an air inlet coaxial with the front disc, the front disc is sequentially provided with a cylindrical surface section, an arc section one and an arc section two from the air inlet to the air outlet, the arc section one and the arc section two are both protruded to the rear disc side, the outer edge of the arc section two is lower than the arc body at the highest position of the arc section two, the axial projection of the rear disc is in a circular ring shape, the cross section of the rear disc is in an arc shape protruding to the direction away from the front disc side, the outer edge of the rear disc is perpendicular to the air outlet, and the axial height of the rear disc is 8%-12% of the outer diameter of the rear disc. The application can reduce flow passage loss, increase air volume and static pressure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fan manufacturing, and particularly relates to a centrifugal fan wheel. BACKGROUND

[0002] The centrifugal fan is a kind of driven fluid mechanism, which is widely used in ventilation, dust removal and cooling of factories, mines, tunnels, cooling towers, ships, buildings and boilers.

[0003] The Chinese patent document discloses a backward type centrifugal fan [application number: 201320671509.X; authorized publication number: CN203548269U], which comprises a motor and a centrifugal fan wheel fixed to the outer rotor of the motor. The centrifugal fan wheel is in a cylindrical shape, and comprises an upper end panel and a lower end panel fixed to the rotor of the motor. An air inlet is formed on the lower end panel. A plurality of guide vanes are fixed between the upper end panel and the lower end panel, which can form a guide air duct with the inner side wall of the upper end panel and the inner side wall of the lower end panel. The guide vanes are in an arc-shaped sheet shape, and each guide vane is provided with guide ribs one and two.

[0004] The backward type centrifugal fan can increase the air volume by the setting of the guide ribs one and two, but the flow passage loss is large, the air volume is still not ideal, and the static pressure and static pressure efficiency are not high enough. SUMMARY

[0005] The present application aims to solve the above problems in the prior art, and provides a centrifugal fan wheel which can reduce the flow passage loss, increase the air volume and static pressure.

[0006] The purpose of the present application can be achieved by the following technical scheme: a centrifugal fan wheel, comprising a front disc, a rear disc and a plurality of blades, the blades are circumferentially and uniformly fixed between the front disc and the rear disc, the front disc and the rear disc are connected by an air outlet, the middle part of the front disc is provided with an air inlet coaxially arranged with the front disc, characterized in that the front disc is sequentially provided with a cylindrical surface section, a circular arc section one and a circular arc section two from the air inlet to the air outlet, the circular arc section one and the circular arc section two are protruded to the rear disc side, the outer edge of the circular arc section two is lower than the arc body at the highest position of the circular arc section two, the axial projection of the rear disc is in a circular ring shape, the cross section of the rear disc is in a circular arc shape protruding to the direction away from the front disc, and the outer edge of the rear disc is perpendicular to the air outlet, and the axial height of the rear disc is 8%-12% of the outer diameter of the rear disc.

[0007] In the above-mentioned centrifugal fan wheel, the narrowest part of the blade width is located at the midline of the distance between the outer diameter of the front disc and the inner diameter of the front disc, the width between the midline located between the front disc and the rear disc is named as A, and the distance between the narrowest part of the blade width and the midline is less than or equal to 10% A.

[0008] In the centrifugal wind wheel, the blade is a twisted airfoil design, the ratio of the maximum thickness of the blade section to the chord length of the inner end of the blade is 28%-36%, the ratio of the maximum thickness of the blade section to the chord length of the blade is 40‰-46‰, and the upper outlet angle of the blade is smaller than the lower outlet angle, and the difference between the two angles is 4°-12°.

[0009] In the centrifugal wind wheel, the outer edge of the front disc has a flange folded to the side of the cylindrical section, and the inner wall of the flange has a reinforcing rib one uniformly distributed in the circumferential direction and integrated with the bottom surface of the circular arc section two.

[0010] In the centrifugal wind wheel, the top surface of the rear disc has a ring-shaped boss coaxially arranged thereon, and the outer wall of the ring-shaped boss has a reinforcing rib two uniformly distributed in the circumferential direction and integrated with the top surface of the rear disc.

[0011] Compared with the prior art, the centrifugal wind wheel has reasonable structure, small flow passage loss, large air volume, large static pressure, high static pressure efficiency, and good use effect. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a perspective view of the centrifugal wind wheel.

[0013] Figure 2 is a front view of the structure of the centrifugal wind wheel.

[0014] Figure 3 is a sectional view of the structure of the centrifugal wind wheel.

[0015] Figure 4 is a bottom view of the structure of the blade in the centrifugal wind wheel.

[0016] In the figure, 1 is a front disc, 11 is a cylindrical section, 12 is a circular arc section one, 13 is a circular arc section two, 2 is a rear disc, 3 is a blade, 4 is an air outlet, 5 is an air inlet, a is the maximum thickness of the blade section, b is the chord length of the inner end of the blade, c is the chord length of the blade, d is the upper outlet angle, e is the lower outlet angle, 6 is a flange, 7 is a reinforcing rib one, 8 is a ring-shaped boss, and 9 is a reinforcing rib two. DETAILED DESCRIPTION

[0017] The following is a specific embodiment of the present application and further describes the technical solutions of the present application in conjunction with the drawings, but the present application is not limited to these embodiments.

[0018] As Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the centrifugal fan wheel includes a front disc 1, a rear disc 2 and a plurality of blades 3, the blades 3 are circumferentially and uniformly fixed between the front disc 1 and the rear disc 2, the front disc 1 and the rear disc 2 are an air outlet 4, the front disc 1 has an air inlet 5 coaxially arranged in the middle, the front disc 1 is sequentially provided with a cylindrical surface section 11, an arc section one 12 and an arc section two 13 from the air inlet 5 to the air outlet 4, the arc section one 12 and the arc section two 13 are both protruded to the rear disc 2 side, the outer edge of the arc section two 13 is lower than the arc body at the highest position of the arc section two 13, the axial projection of the rear disc 2 is in a circular ring shape, the cross section of the rear disc 2 is in a circular arc shape protruding to the side away from the front disc 1, and the outer edge of the rear disc 2 is perpendicular to the air outlet 4, and the axial height of the rear disc 2 is 8%-12% of the outer diameter thereof.

[0019] The centrifugal fan wheel has the structure optimization of the front disc 1 and the rear disc 2, the outward turning of the arc section two 13, the widened width of the air outlet 4, the good guiding and flow guiding effect of the arc section one 12, the arc section two 13 and the rear disc 2, the reduced flow passage loss, the increased air volume and static pressure, the improved static pressure efficiency and the good use effect. In the embodiment, the axial height of the rear disc 2 is 10% of the outer diameter thereof.

[0020] The related test data about the shape of the front disc 1 is as follows:

[0021] Front disc shape Impeller rotation speed RPM Maximum air volume m3 / h Maximum static pressure Pa Maximum static pressure efficiency % Cylindrical surface section + circular arc section + horizontal surface 2550 1425 618 65.4 Cylindrical surface section + circular arc section + conical surface section 2550 1433 612 65.8 Cylindrical surface section + circular arc section + circular arc section two (the present application) 2550 1500 650 68.3

[0022] The related test data about the axial height of the rear disc 2 is as follows:

[0023] Ratio of axial height to outer diameter % Impeller rotation speed RPM Maximum air volume m3 / h Maximum static pressure Pa Maximum static pressure efficiency % 0 2550 1535 582 63.9 10 (the present application) 2550 1500 650 68.3 15 2550 1460 580 64.7

[0024] Further, the narrowest part of the width of the blade 3 is located at the midline of the distance between the outer diameter of the front disc 1 and the inner diameter thereof, the width between the midline located between the front disc 1 and the rear disc 2 is named as A, and the distance between the narrowest part of the width of the blade 3 and the midline is less than or equal to 10% A. Such layout is reasonable, so that the airflow forms the effect of accelerating first and then decelerating in the flow passage, the flow loss is reduced, the air volume and the static pressure are increased, and in the embodiment, the distance between the narrowest part of the width of the blade 3 and the midline is 5% A.

[0025] The blade 3 is a twisted airfoil design, the ratio of the maximum thickness of the blade section to the chord length b of the inner end of the blade and the chord length c of the blade is 28%-36%, the ratio of the maximum thickness of the blade to the chord length c of the blade is 40‰-46‰, and the upper outlet angle d of the blade 3 is smaller than the lower outlet angle e, and the difference between the two angles is 4°-12°. The angle between the outer end surface of the outer edge of the front disc 1 and the tangent plane of the circumferential surface is the upper outlet angle d, and the angle between the outer end surface of the outer edge of the rear disc 2 and the tangent plane of the circumferential surface is the lower outlet angle e. In this way, the blade 3 is reasonably designed, the flow guiding effect of the blade 3 is good, the air volume is large, the static pressure is large, and the static pressure efficiency is high. In the embodiment, the ratio of the maximum thickness of the blade section to the chord length b of the inner end of the blade and the chord length c of the blade is 32%, the ratio of the maximum thickness a of the blade section to the chord length c of the blade is 41‰, the upper outlet angle d of the blade 3 is smaller than the lower outlet angle e, and the difference between the two angles is 7°, and the lower outlet angle e is 34°.

[0026] The relevant test data of the shape of the blade 3 are as follows:

[0027] Blade shape Difference between upper and lower outlet angles ° Impeller rotation speed RPM Maximum air volume m3 / h Maximum static pressure Pa Maximum static pressure efficiency % Single plate 0 2550 1370 568 57.3 Airfoil normal 0 2550 1428 613 63.4 Airfoil (the present application) 4 2550 1479 638 66.2 Airfoil (the present application) 7 2550 1500 650 68.3 Airfoil (the present application) 10 2550 1480 635 66.3 Airfoil (the present application) 12 2550 1440 617 66.9

[0028] The maximum air volume of the centrifugal fan reaches 1500 m3 / h, the highest static pressure reaches 650 Pa, and the maximum static pressure efficiency reaches 68.3% when the rotating speed is 2550 RPM.

[0029] The outer edge of the front disc 1 has a flange 6 that is folded to the side of the cylindrical surface section 11. The inner wall of the flange 6 has a reinforcing rib 7 that is uniformly distributed in the circumferential direction and is integrated with the bottom surface of the second circular arc section 13. The reinforcing rib 7 is in a triangular shape. The flange 6 and the reinforcing rib 7 not only increase the structural strength of the front disc 1, but also facilitate the installation of the balance block. In dynamic balance checking, the flange 6 can serve as an angle identifier. In addition, the flange 6 plays a flow guiding role, and there will be no backflow at the air supply outlet, so the air supply is smooth.

[0030] The top surface of the rear disc 2 has an annular boss 8 that is coaxially arranged thereon. The outer wall of the annular boss 8 has a reinforcing rib 9 that is uniformly distributed in the circumferential direction and is integrated with the top surface of the rear disc 2. The reinforcing rib 9 is in a triangular shape. The annular boss 8 and the reinforcing rib 9 not only increase the structural strength of the rear disc 2, but also facilitate the installation of the balance block. In dynamic balance checking, the annular boss 8 can serve as an angle identifier, which is convenient to operate. The balance block at the flange 6 and the annular boss 8 is out of the flow range, and will not adversely affect the airflow.

[0031] The contents not described in detail in the specification belong to the prior art known to those skilled in the art. The specific embodiments described herein are only illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, without departing from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A centrifugal impeller, comprising a front disc (1), a rear disc (2), and a plurality of blades (3), wherein the blades (3) are circumferentially and uniformly fixed between the front disc (1) and the rear disc (2), the space between the front disc (1) and the rear disc (2) is an air outlet (4), and the front disc (1) has an air inlet (5) coaxially arranged therewith in the middle, characterized in that, The front plate (1) consists of a cylindrical section (11), an arc section one (12), and an arc section two (13) in sequence from the air inlet (5) to the air outlet (4). Both the arc section one (12) and the arc section two (13) protrude towards the rear plate (2). The outer edge of the arc section two (13) is lower than the arc body at the highest point of the arc section two (13). The axial projection of the rear plate (2) is annular. The cross section of the rear plate (2) is an arc protruding away from the front plate (1), and the outer edge of the rear plate (2) is perpendicular to the air outlet (4). The axial height of the rear plate (2) is 8%-12% of its outer diameter.

2. A centrifugal impeller according to claim 1, characterized in that, The narrowest point of the blade (3) is located at the perpendicular bisector of the distance between the outer diameter and the inner diameter of the front disc (1). The width of the perpendicular bisector between the front disc (1) and the rear disc (2) is named A. The distance from the narrowest point of the blade (3) to the perpendicular bisector is less than or equal to 10%A.

3. A centrifugal impeller according to claim 1 or 2, characterized in that, The blade (3) is a twisted airfoil design. The ratio of the maximum thickness of the blade section to the chord length (b) at the inner end of the blade to the blade chord length (c) is 28%-36%, and the ratio of the maximum thickness of the blade section (a) to the blade chord length (c) is 40‰-46‰. The upper exit angle (d) of the blade (3) is smaller than the lower exit angle (e), and the difference between the two angles is 4°-12°.

4. A centrifugal impeller according to claim 3, characterized in that, The outer edge of the front plate (1) has a flange (6) that folds towards the cylindrical section (11). The inner wall of the flange (6) has a reinforcing rib (7) that is evenly distributed around the circumference and is integrated with the bottom surface of the arc section (13). The reinforcing rib (7) is triangular in shape.

5. A centrifugal impeller according to claim 4, characterized in that, The top surface of the rear plate (2) has a ring-shaped boss (8) coaxially arranged therewith. The outer wall of the ring-shaped boss (8) has a reinforcing rib (9) evenly distributed around the circumference and integrated with the top surface of the rear plate (2). The reinforcing rib (9) is triangular in shape.

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