Double-outlet centrifugal fan

Abstract

A double-outlet centrifugal fan comprises a volute, an impeller and air inlets, two air outlets are formed in the side wall of the volute, and volute tongues are arranged between the sides, close to the impeller, of the air outlets and the volute. The distance between the impeller and the side wall of the volute is increased, the distance between the impeller and the volute tongue is controlled, and the ratio of the two distances is within a proper range, so that the maximum opening degree of an air outlet is increased, and meanwhile, the equivalent expansion area of the volute is ensured; the divergence angle between the volute tongue and the air outlet is controlled to be 15-30 degrees, the flow speed of an outlet of the volute is reduced, and the diffusion effect of the volute is improved; the angle between the center of the volute tongue and the center of the volute is controlled to be 35-48 degrees, the depth of the volute tongue is increased, a shallow volute tongue or a flat volute tongue is changed into the deep volute tongue, the gap between the volute tongue and the impeller is reduced, exposure of the impeller is reduced, circular flow of part of gas in the volute is reduced, and the aerodynamic performance of the fan is improved. And a plurality of guide plates are mounted at the outlet, so that the gas flowing state at the air outlet is effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to centrifugal fan field especially relates to a double outlet centrifugal fan. BACKGROUND

[0002] The fan is mainly used for conveying various gases in industrial production, and is widely applied to various departments of national economy, and is one of indispensable general equipment in industrial production and civil field, wherein the double outlet centrifugal fan has unique double outlet volute structure, compact structure and simplifies pipeline and reduces overall size of ventilation equipment in industrial practice, so that the double outlet centrifugal fan is more applied in industrial fields such as industrial exhaust, heat sequence and ventilation system.But the double outlet volute of the double outlet centrifugal fan actually applied in industrial production is mostly simply modified according to experience on the aerodynamic profile of single outlet volute, the effect of volute gas collection, flow guide and pressure recovery is reduced, the aerodynamic performance of the fan is generally much lower than that of single outlet conventional centrifugal fan of same type, especially fan efficiency and static pressure are obviously reduced, so improving the aerodynamic performance of the double outlet centrifugal fan has positive significance for the development of industry. SUMMARY

[0003] The utility model aims at providing a double outlet centrifugal fan, and improving the aerodynamic performance of the fan.

[0004] The utility model discloses a double outlet centrifugal fan, including volute, impeller and air inlet, impeller is located inside volute, air inlet is located one side of impeller along the axial direction, and air inlet is installed in the lateral wall of volute, the lateral wall of volute is equipped with two air outlets, the plane of air outlet is parallel with the axis of impeller, the side of air outlet away from impeller has a section of distal end lateral wall perpendicular to the plane of air outlet, and the distal end lateral wall and the arc lateral wall of volute are smoothly connected, the side of air outlet close to impeller and the arc lateral wall of volute are equipped with volute tongue, the side of volute tongue connected with air outlet has a section of diffusion lateral wall, and the diffusion angle F between diffusion lateral wall and distal end lateral wall is 15 ~30 °;The minimum distance between the outside edge of impeller and distal end lateral wall is defined as A1, and the minimum distance between the outside edge of impeller and volute tongue is defined as A2, A2=(0.035 ~0.085)D, D is the diameter of impeller, and A1 / A2=4.5 ~8.5;The plane parallel with air outlet and containing the axis of impeller is defined as horizontal reference surface, the plane parallel with distal end lateral wall and containing the axis of impeller is defined as vertical reference surface, the plane containing volute tongue center line and the axis of impeller is defined as volute tongue reference surface, and the angle E between volute tongue reference surface and vertical reference surface is 35 ~ 48 °;

[0005] The inside of the volute is also provided with a plurality of guide vanes, the plurality of guide vanes are divided into two groups corresponding to the two air outlets respectively, the plurality of guide vanes in the same group are distributed at intervals between the volute tongue and the distal end side wall, the outlet end of the guide vane extends to the plane where the air outlet is located, the inlet end of the guide vane is located in the inside of the volute, the inlet end and the outlet end of the guide vane have an arc-shaped curved surface, the guide vane closest to the distal end side wall in the same group is defined as the first guide vane, the guide vane adjacent to the first guide vane in the same group is defined as the second guide vane, the inlet angle of the inlet end of the first guide vane intersected by the horizontal reference plane is β, and β is 40-60°, the inlet angle of the inlet end of the second guide vane intersected by the horizontal reference plane is α, and α is 50-70°, the minimum distance between the outlet end of the first guide vane and the distal end side wall along the horizontal reference plane is defined as L1, the minimum distance between the outlet end of the second guide vane and the distal end side wall along the horizontal reference plane is defined as L2, and the length of the air outlet along the horizontal reference plane is defined as L, L1 / L=0.08-0.15, and L2 / L=0.3-0.6.

[0006] Preferably, the number of guide vanes in the same group is 2-6, and the length of the plurality of guide vanes in the same group decreases in turn along the direction away from the distal end side wall.

[0007] Preferably, the width of the volute along the axial direction of the impeller is defined as B, the width of the position of the outer edge of the impeller along the axial direction is defined as B1, and B / B1=2.15-2.65.

[0008] According to the above technical scheme, the volute has the following beneficial effects:

[0009] The three-dimensional model is established on the basis of experience design, the CFD analysis is carried out on the three-dimensional model of the whole fan, the speed vector and the flow line of the airflow in the numerical simulation result are observed and analyzed, the genetic algorithm is used to optimize the aerodynamic model of the fan, the aerodynamic model with the optimal aerodynamic performance and the minimum flow loss is obtained, the static pressure of the fluid in the inside of the volute is stably increased, the airflow is uniformly flowed, the flow state of the airflow is greatly improved, the useless loss in the inside of the volute is reduced, the aerodynamic parameters and the overall efficiency of the fan are improved, and the specific aspects include the following aspects:

[0010] 1. The distance A1 between the impeller and the distal end side wall is increased, the distance A2 between the impeller and the volute tongue is controlled to be (0.035-0.085)D, and the ratio of A1 / A2 is 4.5-8.5, so that the maximum opening degree of the air outlet is increased, and the equivalent expansion area of the volute is ensured; the diffusion angle F between the volute tongue and the air outlet is 15-30°, the actual area of the volute outlet is further increased, the flow speed of the volute outlet is reduced, and the pressure recovery effect of the volute is improved.

[0011] 2. The angle E between the center of the volute tongue and the center of the volute casing is controlled to be 35~48°. At this angle, the depth of the volute tongue is increased compared to the existing volute tongue of the fan. By optimizing the aerodynamics, the shallow or flat volute tongue is changed to a deep volute tongue, which reduces the gap between the volute tongue and the impeller. This helps to reduce the exposure of the impeller, reduce the circulation of some gas in the volute casing, and improve the aerodynamic performance of the fan.

[0012] 3. Multiple guide vanes are installed at the outlet position. The curved surface of the guide vanes can guide the airflow to the air outlet. By controlling the inlet angle of the two guide vanes furthest from the impeller and their distance from the side wall of the air outlet, the gas flow state at the air outlet position is effectively improved. Attached Figure Description

[0013] Figure 1 This is a side view of a centrifugal fan.

[0014] Figure 2 This is a front view diagram of the inside of the volute.

[0015] The markings in the diagram are: 1. volute, 2. impeller, 3. air inlet, 4. volute tongue, 5. guide vane, 6. air outlet. Detailed Implementation

[0016] Referring to the attached diagram, the specific implementation method is as follows:

[0017] like Figure 1 , 2 As shown, a dual-outlet centrifugal fan includes a volute 1, an impeller 2, and an inlet 3. The impeller 2 is located inside the volute 1, and the inlet 3 is located on one side of the impeller 2 along its axial direction. The inlet 3 is inserted into the side wall of the volute 1, and the side wall of the volute 1 has two outlets 6. The plane containing the outlets 6 is parallel to the axis of the impeller 2. The side of the outlets 6 away from the impeller 2 has a distal sidewall perpendicular to the plane containing the outlets 6, and the distal sidewall smoothly transitions to the arc-shaped sidewall of the volute 1. The width of the volute 1 along the axial direction of the impeller 2 is defined as B, and the width along the axial direction of the outer edge of the impeller 2 is defined as B1, where B / B1 = 2.15~2.65.

[0018] like Figure 2 As shown, a volute tongue 4 is provided between the side of the air outlet 6 near the impeller 2 and the arc-shaped sidewall of the volute 1. The side of the volute tongue 4 connected to the air outlet 6 has a diffuser sidewall. The diffusion angle F between the diffuser sidewall and the far-end sidewall is 15~30°, which can increase the actual area of ​​the volute outlet and reduce the volute outlet velocity, thereby improving the diffusion effect of the volute.

[0019] like Figure 2As shown, the minimum distance between the outer edge of the impeller 2 and the distal side wall is defined as A1, and the minimum distance between the outer edge of the impeller 2 and the volute tongue 4 is defined as A2, A2=(0.035~0.085)D, D is the diameter of the impeller 2, A1 / A2=4.5~8.5. By controlling the ratio of A1 / A2, not only the maximum opening degree of the air outlet is increased, but also the equivalent expansion area of the volute is ensured.

[0020] As shown in the figure, Figure 2 the plane parallel to the air outlet 6 and containing the axis of the impeller 2 is defined as the horizontal reference plane, the plane parallel to the distal side wall and containing the axis of the impeller 2 is defined as the vertical reference plane, and the plane containing both the center line of the volute tongue 4 and the axis of the impeller 2 is defined as the volute tongue reference plane. The angle E between the volute tongue reference plane and the vertical reference plane is 35~48°. Under this angle, the depth of the volute tongue is increased compared with the volute tongue of the existing fan. By aerodynamic optimization, the shallow volute tongue or flat volute tongue is changed to a deep volute tongue, which reduces the gap between the volute tongue and the impeller, is beneficial to reduce the exposure of the impeller, reduce the circulating flow of part of the gas in the volute, and improve the aerodynamic performance of the fan.

[0021] As shown in the figure, Figure 2 the inside of the volute 1 is also provided with a plurality of guide vanes 5, which are divided into two groups corresponding to the two air outlets 6 respectively. The plurality of guide vanes 5 in the same group are distributed between the volute tongue 4 and the distal side wall. The number of guide vanes 5 in the same group is 2~6, and the length of the plurality of guide vanes 5 in the same group decreases in the direction away from the distal side wall. The outlet end of the guide vane 5 extends to the plane where the air outlet 6 is located, the inlet end of the guide vane 5 is located inside the volute 1, and the guide vane 5 has an arc-shaped curved surface between the inlet end and the outlet end. The arc-shaped curved surface can guide the airflow to the air outlet.

[0022] As shown in the figure, Figure 2 the guide vane 5 closest to the distal side wall in the same group is defined as the first guide vane, and the guide vane adjacent to the first guide vane in the same group is defined as the second guide vane. The inlet angle β of the tangent line of the inlet end of the first guide vane intersecting with the horizontal reference plane is 40~60°, and the inlet angle α of the tangent line of the inlet end of the second guide vane intersecting with the horizontal reference plane is 50~70°. The minimum distance between the outlet end of the first guide vane and the distal side wall along the horizontal reference plane is defined as L1, and the minimum distance between the outlet end of the second guide vane and the distal side wall along the horizontal reference plane is defined as L2. The length of the air outlet 6 along the horizontal reference plane is defined as L, L1 / L=0.08~0.15, and L2 / L=0.3~0.6. By controlling the structural parameters of the above two guide vanes, the gas flow state at the air outlet position can be further effectively improved.

[0023] Based on the experience design, the three-dimensional model of the whole fan is established and CFD analysis is carried out. Through observing and analyzing the velocity vector and streamline of the airflow in the numerical simulation results and optimizing the aerodynamic model of the fan by genetic algorithm, the aerodynamic model with the optimal aerodynamic performance and the minimum flow loss is obtained, so that the static pressure of the fluid in the volute increases stably, the airflow flows uniformly, the flow state of the airflow is greatly improved, which helps to reduce the loss of useless work in the volute, and improves the aerodynamic parameters and overall efficiency of the fan.

Claims

1. A double-outlet centrifugal fan, comprising a volute (1), an impeller (2) and an air inlet (3), the impeller (2) being located inside the volute (1), the air inlet (3) being located at one side of the impeller (2) in the axial direction, the air inlet (3) being inserted and installed on the side wall of the volute (1), the side wall of the volute (1) being provided with two air outlets (6), characterized in that: The plane where the air outlet (6) is located is parallel to the axis of the impeller (2), and the side of the air outlet (6) away from the impeller (2) has a distal end side wall perpendicular to the plane where the air outlet (6) is located, the distal end side wall and the arc-shaped side wall of the volute (1) are smoothly transitioned, and the side of the air outlet (6) close to the impeller (2) is provided with a volute tongue (4) between the arc-shaped side wall of the volute (1), the side of the volute tongue (4) connected with the air outlet (6) has a diffusion side wall, the diffusion angle F between the diffusion side wall and the distal end side wall is 15-30°; the minimum distance between the outer edge of the impeller (2) and the distal end side wall is defined as A1, the minimum distance between the outer edge of the impeller (2) and the volute tongue (4) is defined as A2, A2=(0.035-0.085)D, D is the diameter of the impeller (2), A1 / A2=4.5-8.5; the plane parallel to the air outlet (6) and containing the axis of the impeller (2) is defined as the horizontal reference plane, the plane parallel to the distal end side wall and containing the axis of the impeller (2) is defined as the vertical reference plane, and the plane containing the center line of the volute tongue (4) and the axis of the impeller (2) is defined as the volute tongue reference plane, the included angle E between the volute tongue reference plane and the vertical reference plane is 35-48°; The inside of the volute (1) is also provided with a plurality of guide vanes (5), the plurality of guide vanes (5) are divided into two groups corresponding to the two air outlets (6), the plurality of guide vanes (5) in the same group are distributed between the volute tongue (4) and the distal end side wall, the outlet end of the guide vane (5) extends to the plane where the air outlet (6) is located, the inlet end of the guide vane (5) is located inside the volute (1), the inlet end and the outlet end of the guide vane (5) have an arc-shaped curved surface, the guide vane (5) closest to the distal end side wall in the same group is defined as the first guide vane, the guide vane (5) adjacent to the first guide vane in the same group is defined as the second guide vane, the inlet angle of the inlet end tangent of the first guide vane intersecting with the horizontal reference plane is β, and the inlet angle of the inlet end tangent of the second guide vane intersecting with the horizontal reference plane is α, wherein β is 40-60° and α is 50-70°; the minimum distance between the outlet end of the first guide vane and the distal end side wall along the horizontal reference plane is defined as L1, the minimum distance between the outlet end of the second guide vane and the distal end side wall along the horizontal reference plane is defined as L2, and the length of the air outlet (6) along the horizontal reference plane is defined as L, L1 / L=0.08-0.15, and L2 / L=0.3-0.

6.

2. A dual outlet centrifugal fan as claimed in claim 1, characterized in that: The number of guide vanes (5) in the same group is 2-6, and the length of the plurality of guide vanes (5) in the same group decreases in turn in the direction away from the distal end side wall.

3. A dual outlet centrifugal fan as claimed in claim 1, characterized in that: The width of the volute (1) in the axial direction of the impeller (2) is defined as B, and the width of the position of the outer edge of the impeller (2) in the axial direction is defined as B1, B / B1=2.15-2.65.

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