CN115199569A

CN115199569A - Centrifugal fan impeller with throttling wing structure

Info

Publication number: CN115199569A
Application number: CN202210795726.3A
Authority: CN
Inventors: 何坤; 王婷; 刘向阳; 曹伟; 姜泽; 杜荣法
Original assignee: Xian Jiaotong University; Wolong Electric Group Co Ltd
Current assignee: Xian Jiaotong University; Wolong Electric Drive Group Co Ltd
Priority date: 2022-07-07
Filing date: 2022-07-07
Publication date: 2022-10-18

Abstract

The invention discloses a centrifugal fan impeller with a throttling wing structure, which comprises a front disc with an air inlet, a rear disc with a connecting hole for connecting a main shaft system such as a motor and the like, a plurality of blades arranged around the air inlet and distributed around a rotating shaft Z, and a plurality of throttling wings arranged around an air outlet and distributed around the rotating shaft Z, wherein the throttling wings are connected with the front disc, the chord length of each throttling wing is 30-70% of each blade, and the height of each throttling wing is 5-35% of each blade. According to the invention, the throttle wings are arranged on the circumferential direction of the blade, so that the formation of secondary flow can be effectively blocked, the loss of the secondary flow is reduced, and the vortex flow is reduced.

Description

Centrifugal fan impeller with throttling wing structure

Technical Field

The invention belongs to the technical field of centrifugal fan impellers, and particularly relates to a centrifugal fan impeller with a throttling wing structure.

Background

Conventional centrifugal fan impellers have no throttle blade, and when the impeller rotates, the air flow has a strongly varying velocity and pressure distribution, with a local high-velocity region or low-pressure region, not only in the direction of the axis of rotation but also in the circumferential direction, particularly in the vicinity of the front cover. These cause the air current to deflect at the blade suction surface, produce strong secondary flow, cause the secondary flow loss, lead to the loss of static pressure isoaerodynamics, reduce the efficiency of centrifugal fan impeller, increase fan noise.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a centrifugal fan impeller with a throttling wing structure, which can better realize the influence on the air flow under a good mechanical stable state, effectively reduce the secondary flow, and be optimized in the aspects of reducing the pressure loss, reducing the noise, improving the working efficiency of the fan, etc.

The invention is realized by adopting the following technical scheme:

the centrifugal fan impeller with the throttling wing structure comprises a front disc with an air inlet, a rear disc with a connecting hole for connecting a main shaft system such as a motor and the like, a plurality of blades which are arranged around the air inlet and distributed around a rotating shaft Z, and a plurality of throttling wings which are arranged around an air outlet and distributed around the rotating shaft Z, wherein the throttling wings are connected with the front disc, the chord length of each throttling wing is 30-70% of each blade, and the height of each throttling wing is 5-35% of each blade.

The invention is further improved in that the throttling wing is positioned between two adjacent blades, and the installation angle beta epsilon (0-90 degrees).

The invention is further improved in that the blade and the throttle wing rotate around the shaft by an included angle alpha larger than 0 deg.

The invention is further improved in that the throttle wings are directly connected with the correspondingly formed front disc at least on part and can be randomly distributed close to the air outlet in the circumferential direction.

The invention is further improved in that the geometric structure of the throttling wing can be randomly rotated and twisted in three dimensions, and the molded line can be designed according to the flow field condition.

A further development of the invention consists in that a flow channel is formed between each blade and each throttle wing in the circumferential direction.

The invention is further improved in that the flow channel is communicated radially outward from the area of the air inlet through the blades and the throttle blade, and an air outlet is formed in the outer area of the centrifugal fan impeller.

The invention is further improved in that each throttle blade has an axial end face and two radial end faces, the two radial end faces are identical in shape to the front and rear edges of the blade, and a pressure face and a suction face pointing in the circumferential direction are respectively arranged on the two radial end faces.

The invention has at least the following beneficial technical effects:

compared with the traditional centrifugal fan impeller, the centrifugal fan impeller with the throttling wing structure provided by the invention can favorably influence the uniformity of speed distribution and pressure distribution in the direction of a rotating shaft and in the circumferential direction in an airflow channel among the front disk, the rear disk and the blades of the fan.

Meanwhile, the throttle wing structure can effectively block the formation of secondary flow, reduce the loss of the secondary flow and reduce the vortex flow, so that the airflow in the circumferential direction is uniformly distributed, particularly in the flow field near the front disk, the locally-occurring maximum airflow speed is conditionally reduced, the maximum airflow speed has positive influence on the aerodynamic and acoustic characteristics of the fan, and the improvement on static pressure, static pressure efficiency and noise is obvious.

In addition, the invention controls multiple degrees of freedom of airflow flow and airflow guidance in a targeted manner, so that the airflow of the flow channel between the blades is kept stable, the separation trend of the air and the wall surface of the blade is reduced, and the flow field condition of the fan is improved, thereby improving the static pressure rise and static pressure efficiency of the fan and reducing noise.

In addition, the flow condition of the air flow in the flow field of the fan is improved, the mechanical stability is improved to a certain extent, the service life of the equipment is prolonged, the materials are saved, the safety and the economical efficiency of the operation of the equipment are improved, and the development of green and efficient equipment is promoted.

In summary, the throttle blade can be added to a conventional centrifugal fan impeller as long as it is technically feasible.

Drawings

FIG. 1 illustrates a perspective view of a conventional centrifugal fan impeller;

FIG. 2 shows a side view of a centrifugal fan wheel with a throttle blade;

fig. 3 shows a first embodiment of a centrifugal fan wheel with a throttle blade according to the invention, specifically in fig. 3a, in a perspective view, in fig. 3b, in a bottom view of the impeller back disk, and in fig. 3c, in a perspective view, the throttle blade is shown;

FIG. 4 is a diagram showing a blade to throttle blade pressure side comparison for a first embodiment of a centrifugal fan wheel with throttle wings provided in accordance with the present invention;

fig. 5 shows, on an enlarged scale, another perspective view of a first embodiment of a centrifugal fan wheel with throttles provided by the invention, as shown in fig. 3a, for further elucidation of the invention;

fig. 6 to 11 each show a different further exemplary embodiment of a centrifugal fan wheel with a throttle blade according to the invention, wherein each of the sectional views a) and b) shows a bottom view of the impeller back disk and c) shows a perspective view of the throttle blade;

fig. 12 is a comparison graph of characteristic curves of a centrifugal fan impeller with a throttle blade according to the present invention and a conventional centrifugal fan impeller.

Description of reference numerals:

the centrifugal fan comprises a centrifugal fan impeller 1, a front disc 2, a rear disc 3, blades 4, an air inlet 5, an air outlet 6, a throttle wing 7, a connecting hole 8, a flow channel 9, a front half section 10, a rear half section 11 and a molded line 12;

axial end face 13, radial end face a14, radial end face B15, pressure face 16, suction face 17, cutting line 18, chord length 19, height 20.

Detailed Description

The invention provides a centrifugal fan impeller with a throttling wing. In order to make the technical implementation and application of the present invention more clear and intuitive, the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments described herein are merely to illustrate the present invention and are not limited to the throttle blade mentioned herein.

In all embodiments, the centrifugal fan wheel 1 according to the invention, which is to be driven in rotation about a rotational axis Z, comprises a front disk 2, a rear disk 3 which is opposite in the direction of the rotational axis, a plurality of blades 4 and a plurality of throttle wings 7. The front disk 2 has an air inlet 5 for inlet air, which is preferably arranged substantially centrally. The rear disc 3 has a preferably substantially centrally located connection hole 8 for connecting a spindle system such as an electric motor. The blades 4 are mounted between the front disk 2 and the rear disk 3. The blades 4 are at least partially directly connected to both the front disk 2 and the rear disk 3. The blades 4 are arranged in a circumferential distribution around the axis of rotation Z and the air inlet 5. The throttle wing 7 is installed between the front disk 2 and the rear disk 3. The throttle blade 7 is at least partially directly connected to the front disk 2. The throttle foil 7 is mounted between adjacent blades 4. The throttle wings 7 are arranged in a circumferential distribution around the rotation axis Z and the air outlet 6. A flow passage 9 is formed between each blade 4 and each throttle blade 7 in the circumferential direction. The flow channel 9 leads radially outward from the region of the inlet opening 5 via the blades 4 and the throttle blade 7 and forms an outlet opening 6 in the outer region of the centrifugal fan wheel 1.

In the illustrated embodiment of the present invention, the centrifugal fan impeller 1 is the same except that the throttle blades 7 have different shapes and sizes, including the number and arrangement positions of the throttle blades 7. Meanwhile, in the following embodiments, all the throttle blades 7 in each embodiment have the same shape, size, number and arrangement position, and are uniformly distributed in the circumferential direction, and the included angle between the throttle blades and the blades 4 is fixed to be 30 °.

In fig. 2 a side view of a centrifugal fan wheel with a throttle blade is shown. The molded line of the fan front disc 2 consists of a part of circular arc line and a part of straight line. The front half section 10 of the front disk 2 is a 1/4 circle, the starting point is connected with the air inlet and is vertically upward, and the end point horizontally points to the air outlet 6 to form an inner area; the rear half section 11 of the front disk 2 is a straight line extending horizontally towards the air outlet 6, forming an outer edge region. The profile 12 of the fan back disc is a straight line perpendicular to the axis.

In the following, the various embodiments will be described in more detail briefly.

In the first embodiment shown in fig. 3, the throttle blade 7 is a three-dimensional arc with equal thickness, the throttle blade 7 has a thickness of 1.5mm, the throttle blade 7 has the same shape as the blade 4, each throttle blade 7 has an axial end surface 13, a radial end surface a14, and a radial end surface B15, the radial end surfaces a14 and B15 have the same shape as the front and rear edges of the blade 4, and a pressure surface 16 and a suction surface 17 are provided on the two radial end surfaces, respectively, and point in the circumferential direction.

Fig. 4 shows a comparison of a blade and a throttle blade pressure surface of a first embodiment of a centrifugal fan wheel with throttle blades provided by the present invention. The throttle blade 7 is designed by changing the size of the blade 4. The leading edge of the throttle blade 7 is obtained by cutting along a cutting line 18. The cutting line 18 is the line connecting the blade tip profile midpoint of the blade 4 and the blade root profile midpoint of the blade 4. Thus, the chord 19 of the throttle blade 7 is approximately 50% of the chord of the blade 4, and the height 20 of the throttle blade 7 is approximately 12.5% of the height of the blade 4.

Fig. 5 shows, on an enlarged scale, another perspective view of a first embodiment of a centrifugal fan impeller with throttles provided by the invention, shown schematically in fig. 3 a. The 6 blades 4 and the 6 throttle wings 7 are uniformly distributed in the circumferential direction, that is, the rotation between two adjacent blades 4 is 60 ° around the rotation axis Z, and the rotation between two adjacent throttle wings 7 is 60 ° around the rotation axis Z. The blade 4 and the throttle blade 7 rotate around the shaft by an angle of alpha =30 deg.

In the second embodiment shown in fig. 6, the throttle blade 7 is of a uniform thickness straight plate type, the throttle blade 7 has a thickness of 1.5mm, each throttle blade 7 has one axial end surface 13 and two radial end surfaces a14 and B15, and has a pressure surface 16 and a suction surface 17 pointing in the circumferential direction on both surfaces, each being rectangular.

In a third embodiment shown in fig. 7, the throttle blade 7 is of the constant thickness corner type, the throttle blade 7 has a thickness of 1.5mm, each throttle blade 7 has one axial end face 13 and two radial end faces a14 and B15, and has a pressure face 16 and a suction face 17 on both faces, respectively, which are directed in the circumferential direction.

In a fourth embodiment shown in fig. 8, the throttle blade 7 is an airfoil, the thickness of the trailing edge of the throttle blade 7 is 1.5mm, each throttle blade 7 has an axial end face 13 and has a pressure face 16 and a suction face 17 pointing in the circumferential direction on both faces.

In a fifth embodiment shown in fig. 9, the throttle blade 7 is of an equal thickness arc type, the throttle blade 7 has a thickness of 1.5mm, each throttle blade 7 has an axial end face 13 and two radial end faces a14 and B15, and has a pressure face 16 and a suction face 17 on both faces, respectively, which are directed in the circumferential direction.

In the sixth embodiment shown in fig. 10, the throttle blade 7 is of an equal-thickness two-half circular arc shape, the throttle blade 7 has a thickness of 1.5mm, each throttle blade 7 has one axial end surface 13 and two radial end surfaces a14 and B15, and has a pressure surface 16 and a suction surface 17 on both surfaces, respectively, which point in the circumferential direction.

In the seventh embodiment shown in fig. 11, the throttle blade 7 is of an equal thickness wave type, the throttle blade 7 has a thickness of 1.5mm, each throttle blade 7 has one axial end face 13 and two radial end faces a14 and B15, and has a pressure face 16 and a suction face 17 on both faces, respectively, which are directed in the circumferential direction.

FIG. 12 shows the first embodiment of the centrifugal fan impeller with throttling wings provided by the present invention, wherein the air volume of the centrifugal fan impeller with and without throttling wings is from 600m ³ H to 3300m ³ Values under the conditions of/hThe results of the simulation calculation show that the static pressure rise (shown by 2X in fig. 12) of the centrifugal fan impeller with the throttling wings provided in the embodiment is far higher than that (shown by 1X in fig. 12) of the conventional centrifugal fan impeller; the static pressure efficiency (shown as 2Y in figure 12) of the centrifugal fan impeller with the throttling wings provided by the embodiment is far higher than the static pressure rise (shown as 1Y in figure 12) of the traditional centrifugal fan impeller, so that the invention can effectively block the formation of secondary flow and reduce the loss of the secondary flow.

In the embodiment, the front disc 2, the rear disc 3, the blades 4 and the throttle wings 7 are all pp plastic components, and the fan has a small working air volume and a clean operating environment, so that the rigidity and the strength of the fan blades 4 and the throttle wings 7 do not need to be considered. Meanwhile, the secondary flow is blocked by the throttling wing 7, the impact of the fluid on the blade 4 is smaller, the main flow gas between the blade 4 and the throttling wing 7 can blow the low-speed flow gathered in the area between the top of the tail edge of the blade 4 and the front disc 2, the backflow is effectively reduced, and the flow effect and the stability are better. In addition, the shape of the throttle blade 7 in the first embodiment is the same as the shape and the position of the blade 4 are parallel, so that the profile loss of the throttle blade 7 can be smaller, and the energy loss can be further reduced.

In conclusion, the centrifugal fan impeller with the throttle wings provided by the invention can effectively block secondary flow, reduce backflow, reduce fan static pressure loss, improve fan static pressure efficiency, reduce fan noise, prolong the service life of the fan to a certain extent and save resources.

It is to be noted that the same lines may, according to the inventive concept and technique, combine all the individual features mentioned so far arbitrarily, depending on the actual situation.

The invention is not limited to the embodiments described and illustrated above, but also encompasses all structures that perform the same function in the inventive sense. Furthermore, the invention is not limited to the combination of features defined in the independent claims, which can also be defined as any other combination of certain features of the individual features which have been disclosed in their entirety. This means that in principle and in practice each individual feature described in the independent claims can be deleted or replaced by an individual feature disclosed elsewhere in this application. And all such combinations, substitutions or deletions are intended to be within the scope of the appended claims.

Claims

1. The centrifugal fan impeller with the throttling wing structure is characterized in that the centrifugal fan impeller (1) comprises a front disc (2) with an air inlet (5), a rear disc (3) with a connecting hole (8) for connecting a main shaft system such as a motor and the like, a plurality of blades (4) which are arranged around the air inlet (5) and distributed around a rotating shaft Z, and a plurality of throttling wings (7) which are arranged around an air outlet (6) and distributed around the rotating shaft Z, wherein the throttling wings (7) are connected with the front disc (2), the chord length of each throttling wing (7) is 30% -70% of the corresponding blade (4), and the height of each throttling wing (7) is 5% -35% of the corresponding blade (4).

2. The centrifugal fan impeller with throttle wing structure as set forth in claim 1, characterized in that the throttle wing (7) is located between two adjacent said blades (4) with an erection angle β e (0 ° -90 °).

3. Centrifugal fan impeller with throttling wing structure according to claim 1, characterized in that the blade (4) and the throttling wing (7) rotate around the axis by an angle α >0 °.

4. Centrifugal fan wheel with throttling wing structure according to claim 1, characterized in that the throttling wings (7) are directly connected with the correspondingly shaped front disk at least in part and can be randomly distributed in the circumferential direction near the air outlet (6).

5. The centrifugal fan impeller with the throttling wing structure according to claim 1, characterized in that the geometric structure of the throttling wing (7) can be freely rotationally twisted in three dimensions, and the molded line can be designed according to the flow field condition.

6. Centrifugal fan impeller with throttling wing structures according to claim 1, characterized in that a flow channel (9) is formed between each blade (4) and each throttling wing (7) in the circumferential direction.

7. The centrifugal fan wheel with throttle blade structure as claimed in claim 6, characterized in that the flow channel (9) leads radially outwards from the region of the air inlet opening (5) via the blades (4) and the throttle blade (7) and forms an air outlet opening (6) in the outer region of the centrifugal fan wheel (1).

8. Centrifugal fan impeller with throttling wing structure according to claim 1, characterized in that each throttling wing (7) has one axial end face (13) and two radial end faces, both radial end faces having the same shape as the front and rear edges of the blade (4) and on both radial end faces having a pressure face (16) and a suction face (17) pointing in the circumferential direction, respectively.