CN113446237A

CN113446237A - Centrifugal ventilator with semi-open ternary impeller

Info

Publication number: CN113446237A
Application number: CN202110671544.0A
Authority: CN
Inventors: 杨徽; 陈雨彬; 肖康; 王政道; 张炜; 朱祖超
Original assignee: Zhejiang Sci Tech University ZSTU
Current assignee: Zhejiang Sci Tech University ZSTU
Priority date: 2021-06-17
Filing date: 2021-06-17
Publication date: 2021-09-28
Anticipated expiration: 2041-06-17
Also published as: CN113446237B

Abstract

The invention discloses a centrifugal fan with a semi-open three-element impeller, comprising a volute casing, a front side plate and a rear side plate; a collector, one end is connected with the front side plate, and the other end is connected by the front side plate The side plate extends into the volute; the impeller assembly is installed in the volute, and the impeller assembly includes an impeller arranged in the volute and a rotating shaft connected with the impeller and driven by a motor; the impeller includes The impeller rear disk, which can be rotatably arranged in the volute, a plurality of blades connected to the impeller rear disk, and the impeller front disk located on the side of the impeller rear disk close to the front side plate; the blades are located on the impeller front disk and the impeller rear disk. There is a gap between the leading edge of the blade and the front disk of the impeller; the front disk of the impeller is connected to the end of the collector away from the front side plate, and the front disk of the impeller and the collector are integrally cast or seamless connect. In the present invention, the front disc of the impeller and the current collector are integrally cast, so as to reduce the resistance loss of the airflow to the blades near the wheel cover, and achieve the effect of high rotational speed ratio.

Description

Centrifugal ventilator with semi-open ternary impeller

Technical Field

The invention belongs to the technical field of fans, and particularly relates to a centrifugal fan with a semi-open ternary impeller.

Background

The centrifugal fan is a driven fluid machine which increases the pressure of gas and discharges the gas by means of input mechanical energy. The centrifugal fan has wide application range, is used for mine ventilation, boiler air introduction and chemical engineering processes, is used for industrial furnace air blowing, air conditioning, building ventilation and the like, does not need a ventilator, is an important matched device for industrial production, and is also a large household for energy consumption.

The impeller of the traditional centrifugal ventilator adopts a closed structure, the front cover of the impeller is tightly attached to the blade, a gap is reserved between the front cover and the volute of the fan, and air on the high-pressure side of the fan flows back to the low-pressure side through the gap, so that the energy loss of the fan, the noise of the fan, the interference on the air inlet flow field of the fan, and the air outlet quantity and the air pressure of the fan are reduced.

On large-scale equipment such as an engine and the like, a centrifugal ventilator for internal heat exchange needs to be installed to achieve the purpose of rapid heat dissipation. The working space is narrow, the required rotating speed is high, and the requirement of high efficiency cannot be met by the traditional centrifugal fan at present.

Disclosure of Invention

The invention provides a centrifugal ventilator with a semi-open ternary impeller, which has low energy loss and is used for overcoming the defects in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme: a centrifugal ventilator with semi-open ternary impeller comprises

A volute having a front side plate and a rear side plate;

one end of the current collector is connected with the front side plate, and the other end of the current collector extends into the volute from the front side plate;

the impeller assembly is arranged in the volute and comprises an impeller arranged in the volute and a rotating shaft which is connected with the impeller and driven by a motor;

the impeller comprises an impeller rear disc which is rotatably arranged in the volute, a plurality of blades connected with the impeller rear disc, and an impeller front disc which is positioned on one side of the impeller rear disc close to the front side plate; the blades are positioned between the impeller front disk and the impeller rear disk, and a gap is formed between the front edges of the blades and the impeller front disk; the front impeller disc is connected with one end of the current collector, which is far away from the front side plate, and the front impeller disc and the current collector are cast integrally or connected in a seamless mode.

Optionally, the curvature of the profile line of the blade tip of the blade is the same as the curvature of the profile line of the impeller front disk, and the gap between the blade tip of the blade and the impeller front disk is set to be 0.5mm to 1 mm. By arranging the gap, the resistance loss of the airflow to the blade near the wheel cover is reduced, so that the effect of high rotating speed ratio is achieved.

Optionally, a gap between a blade tip of the blade and the impeller front disk is set to be 0.75 mm.

Optionally, the inlet angle of the blade is 30 ° and the outlet angle of the blade is 90 °.

Optionally, the blades are three-dimensionally streamlined and have uniform twisting directions, and the twisting angle of the blades from the impeller inlet to the impeller back plate is 30 °. The twisting direction of each blade is consistent, so that the inlet impact loss of each blade and the separation loss of the tail edge of each blade are reduced, and the optimal aerodynamic performance of the blades is achieved.

Optionally, the plurality of blades comprises long blades and short blades, and the long blades and the short blades are arranged at intervals in a staggered manner. Through the interval setting of long, short blade, utilize short blade to carry out the effect of reposition of redundant personnel to the air current and avoid the formation of air current vortex between the long blade to improve impeller air current's output efficiency.

Optionally, the impeller is a three-dimensional flow impeller, and the outer diameter D of the inlet of the impeller₁84mm, diameter D of the impeller₂Is 105 mm.

Optionally, a volute tongue is arranged at the outlet of the volute, the volute tongue is a short tongue, and a gap t between the top end of the volute tongue and the outer circumference of the impeller is 0.05-0.10D₂The radius of the tip arc of the volute tongue is 4mm, which is 8.5 mm. The volute tongue is arranged to prevent gas from circularly flowing in the volute shell, and the volute tongue adopts a short tongue and is suitable for a high-rotation-speed fan; the radius of the arc at the top end of the volute tongue is set to be 4mm, so that the noise of the fan is reduced.

Optionally, the impeller rear disc is in a horn shape, and a flow guide head is arranged on one side of the impeller rear disc close to the front side plate, and the flow guide head is connected with one end of the rotating shaft close to the flow collector. The rear disc of the impeller is arranged into a horn mouth shape, and the flow guide head is arranged, so that airflow can smoothly enter the impeller, and resistance is reduced.

Optionally, the distance between the back of the impeller and the back side plate is set to be 7-12% of the width between the front side and the back side plate. By limiting the distance between the rear of the impeller and the rear side plate, the generation of vortex, the flow loss and the noise are avoided.

In conclusion, the beneficial effects of the invention are as follows:

1. the front disk of the impeller and the current collector are integrally cast or seamlessly connected, and a gap is reserved between the front disk of the impeller and the current collector, so that the structure is simple, the processing is convenient, air on a high-pressure side can not flow back to a low-pressure side when a fan runs, the resistance loss of airflow to the blades near a wheel cover can be reduced, the effect of high rotating speed ratio is achieved, in addition, the noise of the fan can be reduced, and the air output and the air pressure of the fan are improved;

2. the whole centrifugal ventilator is small in appearance, simple and reasonable in structure, suitable for occasions with various space limitations, capable of achieving high-speed and high-pressure effects and high in operation efficiency.

Drawings

Fig. 1 is a perspective view of the present invention.

Fig. 2 is a cutaway perspective view of fig. 1.

FIG. 3 is a front view of FIG. 1 as viewed in the direction of the volute outlet.

Fig. 4 is a front view of the overall structure of the impeller of fig. 1.

Fig. 5 is an enlarged view of a portion a in fig. 4.

Fig. 6 is a perspective view of a portion of the impeller of fig. 1.

Fig. 7 is a front view of fig. 6.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

Referring to fig. 1 and 2, a centrifugal ventilator with a semi-open ternary impeller comprises a volute 10, an air inlet conduit 20, an air inlet 21, a current collector 31 and an impeller assembly; the volute 10 is a metal shell and is provided with a front side plate 11 and a rear side plate 12; the air inlet guide pipe 20 is arranged on the front side plate 11, the air inlet guide pipe 20 is arranged perpendicular to the front side plate 11, and an air inlet 21 communicated with the space in the volute 10 is formed in the air inlet guide pipe 20; one end of the collector 31 is connected with the front side plate 11 or the air inlet conduit 20, and the other end extends into the volute 10 from the front side plate 11 to guide the gas entering the impeller assembly; the impeller assembly is mounted within the volute 10 for increasing the pressure of the gas and discharging the gas.

Specifically, referring to fig. 1-4 and 6, the impeller assembly includes an impeller and a rotating shaft 41 connected to the impeller; the impeller is a semi-open impeller, is arranged in the volute casing 10 and comprises an impeller rear disk 42, blades and an impeller front disk 44; the impeller rear disk 42 is rotatably arranged in the volute casing 10, and the impeller rear disk 42 is in a horn-shaped shape; a plurality of blades are welded on the impeller rear disk 42 and rotate synchronously with the impeller rear disk 42, the blades are positioned between the impeller front disk 44 and the impeller rear disk 42, and gaps are reserved between the blades and the impeller front disk 44; the impeller front disk 44 is positioned on one side of the impeller rear disk 42 close to the front side plate 11, the impeller front disk 44 is connected with one end of the current collector 31 close to the rear side plate 12 and is integrally cast or connected with the current collector 31 in a seamless mode, no gap exists between the impeller front disk and the current collector 31, the structure is simple, the processing is convenient, and the eddy loss of airflow at the inlet end of the impeller can be reduced; the rotating shaft 41 is connected with the impeller rear disc 42 in a rotation stopping way and is driven by a motor (not shown) to rotate;

referring to FIG. 6, in some embodiments, the impeller is configured as a three-dimensional flow impeller, converting a conventional unitary or binary structure into a ternary structure, the impeller having an inlet outer diameter D₁84mm, diameter D of impeller₂105 mm. Based on a Computational Fluid Dynamics (CFD) technology, a flow field formed when a working medium passes through the interior of the impeller is accurately analyzed, a blade shape which is most suitable for the working medium to pass through the impeller is generated, the flow field is improved, vortex in the impeller is reduced or eliminated, smooth gas flow in the impeller is guaranteed, and the working efficiency is greatly improved.

Referring to fig. 4 and 6, in some embodiments, the plurality of blades include a long blade 431 and a short blade 432, the long blade 431 and the short blade 432 are both provided as ternary blades, the long blade 431 and the short blade 432 are arranged in a staggered and spaced manner, and the short blade 432 is used for shunting the airflow to avoid the formation of airflow vortex between the long blades 431, so as to improve the output efficiency of the impeller airflow; preferably, the number of the long blades 431 is set to 7, and the number of the short blades 432 is also set to 7.

Referring to fig. 4 and 5, in some embodiments, the contour line of the impeller front disk 44 is consistent with the blade top line curvature of the long blades 431 and the short blades 432 (the impeller front disk is consistent with the radian of each blade top), and the gap between the front edges of the long blades 431 and the short blades 432 and the impeller front disk 44 is 0.5mm to 1mm, so that the resistance loss of the airflow to the blades near the impeller front disk 44 is reduced, and the effect of high rotation speed ratio is achieved; preferably, the gap is set to 0.75mm, which is the most effective.

Referring to fig. 4, 6 and 7, in some embodiments, the long blade 431 and the short blade 432 are arc-shaped blade roots and are welded on the rear disc; the top ends of each long blade 431 and each short blade 432 are respectively vertical to the middle shaft, gas axially enters the impeller, the inlet angle of each blade is 30 degrees, the outlet angle of each blade is 90 degrees, and the twisting angle of each blade from the inlet of the impeller to the impeller rear disc 42 is 30 degrees and is in a three-dimensional streamline shape; the twisting direction of each blade is consistent, so that the inlet impact loss of each blade and the separation loss of the tail edge of each blade are reduced, and the optimal aerodynamic performance of the blades is achieved.

Referring to fig. 1-4 and 6, in some embodiments, the diameter of the rotating shaft 41 is 20mm, the length thereof is 47mm, a flow guiding head 51 is connected to an end of the outer diameter of the rotating shaft 41 close to the current collector 31, the flow guiding head 51 is located on a side of the impeller rear disk 42 close to the front side plate 11, and the flow guiding head 51 is in a "bullet head" shape, which helps the air flow to enter the impeller more smoothly, and reduces the resistance.

Referring to fig. 1 and 6, in some embodiments, the front side plate 11 and the rear side plate 12 of the volute 10 are drawn by an archimedes spiral method, and the diameter D of the impeller outlet is measured₂105mm, the pitch is 42.86mm, and the standard polar equation of the archimedean spiral is r (theta) ═ a + b theta; wherein b is an archimedes' spiral coefficient representing the amount of increase (or decrease) in pole diameter per 1 degree of rotation; theta is polar angle, unit is degree, and represents total degree of Archimedes spiral rotation; the variable parameter a will change the shape of the spiral and b controls the distance between the spirals, b being generally constant.

Referring to fig. 1 and 3, in some embodiments, a volute tongue 13 is arranged at the outlet of the volute 10, and the volute tongue 13 is a short tongue and is used for a ventilator with high specific speed. The clearance t between the top end of the volute tongue 13 and the outer circumference of the impeller is (0.05-0.10) D₂The radius of the arc at the top end of the volute tongue 13 is 4mm, which is 8.5 mm. The outlet of the volute 10 is a diffuser pipe, the height H1 of the outlet of the volute 10 is 85.7mm, the width L of the outlet of the volute is 65mm, the vertical height H2 of the whole volute 10 is 164.04mm, and the diffuser effect can be achieved.

Referring to fig. 2, in some embodiments, the distance between the impeller back disk 42 and the rear side plate 12 is about 10% of the width of the front side plate 11 and the rear side plate 12, so as to avoid generating vortex, causing flow loss, and reducing noise; preferably, the impeller back plate 42 is 5mm from the back side plate 12.

Impeller and spiral case design's size is less for the structure of whole fan design is little and efficient, and then occupation space is little, is applicable to the occasion of multiple space restriction, and simple structure is reasonable, and the rotational speed is up to 27974rpm, can reach high rotational speed ratio effect, and the total pressure is up to about 10000pa, and is with low costs, and the practicality is strong. Under the same working condition, the whole machine static pressure efficiency of the traditional centrifugal fan at the designed working condition point is about 65%, and the whole machine running static pressure efficiency of the designed working condition point can reach 70%.

The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.

Claims

1. A centrifugal fan with a semi-open ternary impeller, comprising

a volute (10) having a front side plate (11) and a rear side plate (12);

a collector (31), one end of which is connected to the front side plate (11), and the other end of the collector (31) extends from the front side plate (11) into the volute (10);

An impeller assembly installed in the volute (10), the impeller assembly comprising an impeller disposed in the volute (10) and a rotating shaft (41) connected to the impeller and driven by a motor;

It is characterized in that: the impeller comprises an impeller rear disk (42) rotatably arranged in the volute (10), a plurality of blades connected with the impeller rear disk (42), and a blade located in the impeller rear disk (42) close to the front side plate. (11) A front disk (44) of the impeller on one side; the blade is located between the front disk (44) of the impeller and the rear disk (42) of the impeller, and there is a space between the leading edge of the blade and the front disk (44) of the impeller Clearance; the front disc (44) of the impeller is connected to the end of the collector (31) away from the front side plate (11), and the front disc (44) of the impeller and the collector (31) are integrally cast or seamless connect.

2. A centrifugal fan with a semi-open three-element impeller according to claim 1, wherein the blade tip profile curvature of the blade is the same as the contour curvature of the impeller front disc (44), And the gap between the tip of the blade and the front disc (44) of the impeller is set to 0.5mm˜1mm.

3 . The centrifugal fan with a semi-open three-element impeller according to claim 2 , wherein the gap between the tip of the blade and the front disc ( 44 ) of the impeller is set to 0.75 mm. 4 .

4 . The centrifugal fan with a semi-open three-element impeller according to claim 1 , wherein the inlet angle of the blade is 30°, and the outlet angle of the blade is 90°. 5 .

5. A centrifugal fan with a semi-open three-element impeller according to claim 1, characterized in that: the blades are three-dimensional streamlined and have the same twisting direction, and from the impeller inlet to the impeller rear disc (42), The twist angle of the blades is 30°.

6. A centrifugal fan with a semi-open three-way impeller according to claim 1, characterized in that: the plurality of said blades comprise long blades (431) and short blades (432), and the long blades (432) 431) and short blades (432) are staggered and spaced.

7. a kind of centrifugal fan with semi-open three-element impeller according to claim 1, is characterized in that: described impeller is set as three-element flow impeller, and the outer diameter D _of this impeller inlet is 84mm, impeller _The diameter D2 is 105mm.

8. A centrifugal fan with a semi-open three-element impeller according to claim 7, characterized in that: a volute (13) is provided at the outlet of the volute (10), and the volute (13) A short tongue is used, and the gap t between the top end of the volute tongue (13) and the outer circumference of the impeller is 0.05-0.10D ₂ =8.5mm, and the radius of the arc at the top of the volute tongue (13) is r=4mm.

9. A centrifugal fan with a semi-open three-element impeller according to claim 1, wherein the impeller rear disk (42) is in the shape of a bell mouth, and the impeller rear disk (42) is close to the front side A guide head (51) is provided on one side of the plate (11), and the guide head (51) is connected to the end of the rotating shaft (41) close to the current collector (31).

10. A centrifugal fan with a semi-open three-element impeller according to claim 1, characterized in that: the distance between the rear disk (42) of the impeller and the rear side plate (12) is set as the front side plate ( 7-12% of the width between 11) and the rear side panel (12).