CN100357610C - Axial ventilating machine impellor - Google Patents

Abstract

The invention discloses an axial flow fan impeller. The impeller includes a hub and a plurality of airfoil blades or arc-shaped blades. The blades are arranged around the hub. The blades are bent forward along the direction of rotation, and the forward bending angle of each section of the blades increases continuously from the root to the tip. The forward bending angle of the blade root section is zero, and the forward bending angle of the blade tip section is the largest; the blade is swept forward toward the air intake direction. The advantage of the invention is that the separation of the boundary layer on the surface of the blade is controlled and suppressed through the sweep angle of the blade, the loss of the blade is reduced, the efficiency of the fan is improved, and the aerodynamic noise is also reduced. Through model-level experiments, the blower fan of the invention has low noise, small flow loss and high efficiency. The invention can be widely used in industrial and civil ventilation and process flow.

Description

Axial fan impeller

technical field

The present invention relates to an impeller, and more particularly, it relates to an impeller for an axial flow fan.

Background technique

Existing axial flow fans generally adopt airfoil blades or circular arc plate blades. In the aerodynamic design and geometric modeling of the blade, the general design theory of full three-dimensional radial balance is adopted. The bending and sweep of moving and stationary blades are not considered as design parameters. When geometric blades are formed, the blades are formed by superimposing the center of the primitive blade cascade profile along the radial direction. This design method and blade forming method cannot control the velocity distribution in the blade passage by changing the magnitude and direction of the blade force in the blade row, nor can it control the separation of the airflow in the blade passage, the strength of the vortex and the intensity of the secondary flow, etc. The secondary flow related to the loss causes the existing axial fans to have disadvantages such as high fan noise and low efficiency.

Contents of the invention

One of the purposes of the present invention is to overcome the shortcomings of high noise and low efficiency in the existing axial flow fans; the second purpose is to reduce flow loss and aerodynamic noise through multi-parameter control such as blade curvature and sweep; thus providing a Axial fan impeller.

Technical scheme of the present invention is:

An axial flow fan impeller provided by the present invention includes a hub 7 and a plurality of airfoil blades or circular arc plate blades 8, the blades 8 are arranged around the hub 7, and the blades 8 are bent forward along the direction of rotation thereof, and the blades 8 The forward curvature of each section I～VI increases continuously from the blade root to the blade tip, the forward curvature of the blade root section VI is zero, and the forward curvature of the blade tip section I is the largest.

The forward curvature angle ε of the tip section I of the blade 8 is 34°.

The blades 8 are swept forward toward the air intake direction, with a forward sweep angle α=20°-30°.

The installation angle β _A of each section I-VI of the blade 8 decreases continuously from the blade root to the blade tip, and the installation angle β _A is between 18° and 60°.

The blade 8 and the hub 7 adopt an integral casting structure, or are connected by welding or riveting. The impeller includes 2 to 20 blades 8 with the same shape.

Compared with the prior art, the advantage of the present invention is that the separation of the boundary layer on the surface of the blade is controlled and suppressed through the sweep angle of the blade, the loss of the blade is reduced, the efficiency of the fan is improved, and the aerodynamic noise is also reduced. Through model-level experiments, the blower fan of the invention has low noise, small flow loss and high efficiency. The invention can be widely used in industrial and civil ventilation and process flow.

Description of drawings

Fig. 1 is the structural representation of axial fan impeller of the present invention;

Fig. 2 is a side view of the axial flow fan impeller of the present invention;

Fig. 3 is the schematic diagram of blade in r-θ plane;

Fig. 4 is a schematic diagram of the blade in the r-z plane;

Illustration

Blade Section I～VI Hub 7 Blade 8 Blade Centerline 9

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

For the convenience of description, the cylindrical coordinate system (r, θ, z) is adopted here, with the center O of the hub 7 as the center, r is the radial direction of the hub 7, that is, the extension direction of each installation section of the blade 8, and θ is the vector in The included angle between the circumferential plane of the hub 7 and r, and z is the axial direction of the hub 7 .

The structural diagram of the impeller of the axial flow fan of the present invention in the r-θ plane is shown in FIG. 1 , and an integral casting structure is adopted between the hub 7 and the four blades 8 of the same shape. According to the specific application, the hub 7 and the blade 8 can also be connected by welding or riveting, the number of 8 blades can vary between 2 and 20, and the basic blade shape of the blade 8 can be an airfoil shape or an arc plate leaf type. As a feature of the invention, the blades 8 are forward curved in the r-θ plane in the direction of blade rotation shown in FIG. 1 . As another feature of the present invention, the vanes 8 are generally swept forward in the air intake direction, and the forward sweep angle is α, as shown in Figure 2

The distribution of the front bending angles of each section of the blade 8 can be seen most clearly in Fig. 3. In Fig. 3, 6 representative sections are selected and represented by Roman numerals I~VI, and symbols O ₁ ~ O ₆ are used to represent the angles of the corresponding sections. The center position, where section I is the section of the blade tip, and section VI is the section of the blade root. The connecting line between the center O ₆ of the blade root section VI and the center O of the hub circle is OO ₆ , and the forward bending angle refers to the angle between the line connecting the center of each section and the center O of the hub circle and OO ₆ , for example, section V The forward bending angle is the angle between OO ₅ and OO ₆ . Fig. 3 also provides the specific values of the forward bending angles of each representative section in this embodiment, the forward bending angle of the blade root section VI is 0, the forward bending angle of the section V is 8°, and the forward bending angle of the section IV The forward bending angle of section III is 21°, the forward bending angle of section II is 28°, and the forward bending angle of blade tip section I is 34°. It can be seen that the forward camber angles of each section increase continuously from the blade root section VI, and reach the maximum at the blade tip section I.

The overall forward sweep of the blade 8 toward the air intake direction can be seen most clearly in FIG. 4 , which is a schematic diagram of the blade 8 on the rz plane. The line connecting the center positions of each section of the blade 8 is called the blade centerline 9. In the rz plane, the blade centerline 9 is a straight line, and the sweep angle of the blade refers to the distance between the blade centerline 9 and the aforementioned connection line OO ₆ . The angle between them, in this embodiment, the forward sweep angle α=22°.

Similar to the design of the existing blades, each section of the blade 8 of the present invention has an installation angle β _A and a certain chord length. Table 1 shows the main design parameters of the blade 8 in this embodiment, including the installation angle β _A , the chord length, the forward bending angle and the forward sweeping angle of each representative section I-VI. The chord length of the section I～VI refers to the distance between the two ends of the section of the blade. In FIG. ' and 2", the chord length is the distance between the endpoints 2' and 2".

Table 1

Claims (7)

1, a kind of axial fan impeller, comprise wheel hub (7) and a plurality of wing blade profile or circular arc plate blade profile blade (8), blade (8) is provided with around wheel hub (7), it is characterized in that, described blade (8) is antecurvature along its sense of rotation, and (kyphotic angle of I～VI) increases continuously from the blade root to the blade tip, and the kyphotic angle of blade root cross section (VI) is zero in blade (8) each cross section, the kyphotic angle maximum in blade tip cross section (I), kyphotic angle ε=34 in the blade tip cross section (I) of described blade (8) °.

2, axial fan impeller according to claim 1 is characterized in that, described blade (8) is to the airintake direction sweepforward.

3, axial fan impeller according to claim 2 is characterized in that, described blade (8) sweepforward angle α=20 °～30 °.

4, axial fan impeller according to claim 1 is characterized in that, each cross section of described blade (8) (established angle β of I～VI) _AFrom the blade root to the blade tip, reduce continuously.

5, axial fan impeller according to claim 4 is characterized in that, each cross section of described blade (8) (established angle β of I～VI) _ABetween 18 °～60 °.

6, axial fan impeller according to claim 1 is characterized in that, described blade (8) adopts the cast inblock structure with wheel hub (7), perhaps adopts welding or riveted joint mode to connect.

7, axial fan impeller according to claim 1 is characterized in that, described impeller comprises 2～20 blades (8) that shape is identical.

Images