CN211370769U

CN211370769U - High-speed centrifugal blower

Info

Publication number: CN211370769U
Application number: CN201921830323.8U
Authority: CN
Inventors: 倪奇峰; 吴小佳; 刘梦飞; 沈良成
Original assignee: Anhui Hudu Keda Fluid Machinery Co ltd
Current assignee: Anhui Hudu Keda Fluid Machinery Co ltd
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2020-08-28
Anticipated expiration: 2029-10-28

Abstract

The utility model discloses a high-speed centrifugal blower belongs to mechanical technical field. The problem to the air-blower flow control scope among the prior art little and the job stabilization nature is poor, the utility model provides a high-speed centrifugal blower, it includes the spiral case, is provided with the impeller in the spiral case, and the impeller is connected with actuating mechanism, is provided with the blade on the impeller, still is provided with the diffuser in the spiral case, still includes outer cartridge receiver, and outer cartridge receiver sets up the side of admitting air at the impeller, is provided with interior cartridge receiver in the outer cartridge receiver, is provided with the backward flow groove between outer cartridge receiver and the interior cartridge receiver, and backward flow groove one end is connected with the wheel lid at blade top, and the other end is towards the impeller inlet end. The utility model increases the through flow of the impeller inlet through the arrangement of the reflux groove, thereby reducing the attack angle of the blade, reducing the load and postponing the surge phenomenon; effectively reduce the air current and block, widen the stable working range of air-blower, enlarged the flow control range of air-blower unit, satisfy the operating mode that changes bigger.

Description

High-speed centrifugal blower

Technical Field

The utility model belongs to the technical field of machinery, more specifically say, relate to a high-speed centrifugal blower.

Background

The high-speed centrifugal blower is widely applied to the industrial fields of sewage treatment, desulfurization and denitrification, chemical industry, steel and the like, the centrifugal blower with fixed geometry and fixed rotating speed has a constant working characteristic line, when the working flow is larger than the flow of a design point to a certain degree, the performance of the blower is rapidly deteriorated, the pressure and the efficiency are greatly reduced, and the blower is called as a blocking working condition; when the working flow is smaller than the design point flow to a certain extent, the flow and the exhaust pressure of the blower periodically fluctuate with low frequency and large amplitude, and the unit vibrates violently, which is called surging. Certain applications, such as sewage aeration, have high requirements for a stable working flow range and high requirements for the flow regulation capacity of a blower. At present, two ideas are roughly provided for widening the stable working range of the blower, one is that aiming at a centrifugal blower with fixed geometry and fixed rotating speed, the flow of a surge boundary point is reduced, namely stability expansion is short, the currently researched technologies comprise technical means such as casing treatment, blade tip air injection and plasma control, wherein the casing treatment is relatively outstanding with relatively low cost and obvious effect; the other is the idea of changing geometry and rotating speed, wherein the rotating speed is changed by changing the input rotating speed of the impeller, the variable geometry means mainly comprises an inlet guide vane and an outlet guide vane which can be adjusted, a diffuser with adjustable throat area, a vaneless diffuser with variable width and the like, and the flow regulation effect obtained by the technical means is obvious, but the corresponding structure is complex, the control difficulty is increased, and the unit cost is increased.

Corresponding improvement is also carried out to above-mentioned problem, for example chinese patent application No. CN201120303160.5, the publication date is 2012, 5, month and 2, this patent discloses a high-efficient energy-saving type single-stage high-speed centrifugal blower includes high-speed gear box, spiral case, impeller, air inlet body, entry stator and entry stator adjustment mechanism, the characteristic is: still including export stator and export stator adjustment mechanism, a plurality of export stator is installed in the corresponding axle hole on the high-speed axle end flange of high-speed gear box to radially be the equipartition state, export stator adjustment mechanism connects on the axle of export stator. The disadvantages of the patent are that: the structure is comparatively complicated and the flow control effect of air-blower is general.

As another example, chinese patent application No. CN201721439188.5, published as 2018, 7, and 17, discloses a single-stage assembled centrifugal blower, comprising: the impeller comprises an impeller, a volute in which the impeller is arranged, and a gear transmission device for providing rotary power of the impeller, wherein a diffuser is arranged at an inlet of a rotary channel of the volute, a support is arranged in the volute, an end plate is arranged at the front end of the support, the rear end of the support is connected with a ring, a detachable gasket is arranged at the connecting position of the support and the ring, and an annular gap is formed between the highest point of the ring and the impeller; the impeller is driven by the rotation of the gear transmission device, and airflow enters the rotating shell of the volute through the impeller and the diffuser. The disadvantages of the patent are that: the adjusting range of the blower is limited, and the whole structure is complex.

Disclosure of Invention

1. Problems to be solved

To the problem that the air-blower flow control scope among the prior art is little and job stabilization nature is poor, the utility model provides a high-speed centrifugal air-blower. The utility model discloses effectively improve air-blower flow control scope and make the job stabilization nature of air-blower higher, overall structure is simple.

2. Technical scheme

In order to solve the above problems, the utility model adopts the following technical proposal.

A high-speed centrifugal blower comprises a volute, wherein an impeller is arranged in the volute and connected with a driving mechanism, blades are arranged on the impeller, a diffuser is further arranged in the volute, the high-speed centrifugal blower further comprises an outer casing, the outer casing is arranged on the air inlet side of the impeller, an inner casing is arranged in the outer casing, a backflow groove is arranged between the outer casing and the inner casing, one end of the backflow groove is connected with a wheel cover at the top of each blade, and the other end of the backflow groove faces the air inlet end of the impeller. The load is reduced, the surge phenomenon is delayed, the flow regulation range is wide, the structure is simple, and the work is stable.

Furthermore, the inner casing is fixed in the outer casing through a plurality of support plates. The stability between the inner casing and the outer casing is improved.

Furthermore, the support plate is blade-shaped. Reducing gas flow rate losses.

Furthermore, the number of the support plates is 4-6.

Furthermore, the front end of the outer casing is provided with an inlet guide vane. The gas is guided, and the working range of the centrifugal blower is widened by matching with the backflow groove, and the working efficiency is high and stable.

Furthermore, the inlet guide vane is made of stainless steel. High abrasion resistance and high strength.

Further, the diffuser is a vaneless diffuser. The working range of the centrifugal blower is improved, and the structure is simple.

Furthermore, the blade comprises a plurality of main blade bodies, a sub-blade body is arranged between every two adjacent main blade bodies, and one end of the backflow groove is connected with a wheel cover at the top of each main blade body. So that the overall working efficiency of the impeller is improved.

Furthermore, the impeller and the blades are made of aluminum alloy. The weight is light and the strength is high.

3. Advantageous effects

Compared with the prior art, the beneficial effects of the utility model are that:

(1) the utility model discloses be provided with the backward flow groove between inside and outside quick-witted casket, the one end of backward flow groove is connected with the wheel cap at blade top, the other end is towards the inlet end of impeller, blade top load is crescent at the during operation, the pressure at blade rear portion is higher, the setting of backward flow groove can make partial low kinetic energy fluid automatically enter into the backward flow groove and flow back, collect with impeller inlet end mainstream again, the through flow volume of impeller import has been increased to reduce the blade angle of attack, reduced the load, delayed surge phenomenon's emergence, the flow control range is wide, simple structure;

(2) the inner casing is fixed in the outer casing through a plurality of support plates, so that the connection relationship between the inner casing and the outer casing is stable, and the inner casing and the outer casing are not easy to separate due to the flowing process of high-speed fluid; the support plate is in a blade shape, so that the loss of fluid backflow can be reduced;

(3) the utility model is provided with an inlet guide vane at the front end of the outer casing, the inlet guide vane is arranged to guide and adjust the fluid entering the impeller, and the inlet guide vane can rotate along the rotating shaft to adjust the outlet airflow angle of the inlet guide vane, namely the prewhirl angle of the impeller; the structure is simple, and the adjustment is convenient; the inlet vanes are made of stainless steel, so that the inlet vanes have certain strength and wear resistance, and the service life of the inlet guide vanes is effectively prolonged;

(4) the diffuser in the volute of the utility model is a vaneless diffuser which can reduce the fluid expansion loss, improve the working efficiency and has simple structure, and the vaneless diffuser has no vibration phenomenon caused by mutual interference between the blades and the impeller, so that the problem of fatigue failure caused by mutual vibration between the blades and the impeller does not exist, and the working range of the high-speed centrifugal blower is wide;

(5) the utility model discloses well blade includes a plurality of main blade body and divides the blade body, and main blade body and branch blade body are connected for whole impeller has higher work efficiency, and the material of blade and impeller is the aluminum alloy, satisfies certain intensity requirement again when the quality is light.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a diagram illustrating a non-prerotation working state of a blade;

FIG. 3 is a diagram illustrating a forward pre-rotation operation state of the blade;

FIG. 4 is a diagram of negative pre-selection operating conditions of the blades.

In the figure: 1. inlet guide vanes; 2. an inner case; 3. a support plate; 4. an outer case; 5. an impeller; 6. a reflux tank.

Detailed Description

The invention will be further described with reference to specific embodiments and drawings.

Example 1

As shown in fig. 1, a high-speed centrifugal blower includes a volute, an impeller 5 is disposed in the volute, the impeller 5 is connected to a driving mechanism, the driving mechanism drives the impeller 5 to rotate, and the driving mechanism can be a driving mechanism in the prior art, such as a motor-driven or gear-driven driving mechanism, so that the driving mechanism is not described in detail in the present invention; a diffuser is further arranged in the volute, specifically, the diffuser is arranged at the inlet of a rotating channel of the volute, and gas enters the diffuser after passing through the impeller 5 to slow the flow velocity of the gas and convert the kinetic energy of the gas into pressure energy; the impeller 5 is provided with blades and further comprises an outer casing 4, the outer casing 4 is arranged on the air inlet side of the impeller 5, an inner casing 2 is arranged in the outer casing 4, a backflow groove 6 is arranged between the outer casing 4 and the inner casing 2, the backflow groove 6 is connected with a wheel cover at the top of each blade, and the other end of the backflow groove faces the air inlet end of the impeller 5; when the impeller 5 is close to a surge boundary in an operating condition, the load of the blades on the impeller 5 is gradually increased at the top of the blades, so that the blockage condition is serious, and the pressure at the rear parts of the blades is higher, so that one end of the backflow groove 6 is connected with a wheel cover at the top of the blades, and the load and the blockage condition at the top of the blades are reduced; secondly, the arrangement of the reflux groove 6 can ensure that part of low kinetic energy fluid automatically enters the reflux groove 6 to reflux and then is converged with main flow at the air inlet end of the impeller, and the dotted line with an arrow in the figure 1 is a gas reflux path when the high-speed centrifugal blower is close to surging; the through flow of the inlet of the impeller 5 is increased, so that the attack angle of the blade is reduced, the load of the blade is reduced, the occurrence of a surge phenomenon is delayed, the flow regulation range is wide, and the structure is simple.

As shown in fig. 2, 3 and 4, C1 represents the impeller inlet absolute velocity, U1 represents the impeller inlet bulk velocity, W1 represents the impeller inlet relative velocity, C1 is divided into C1a and C1U along the axial direction and the tangential direction, C1 ' represents the impeller inlet absolute velocity in the low flow state, W1 ' represents the impeller inlet relative velocity in the low flow state, and U1 ' represents the impeller inlet bulk velocity in the low flow state; ' represents a low flow state; according to the euler turbine equation, the energy transferred to a unit mass of gas when the centrifugal impeller 5 rotates is determined by the following equation:

W＝C2u*U2-C1u*U1

in the formula: w represents energy; c2u represents the component velocity of the impeller outlet absolute velocity in the tangential direction; c1u represents the component velocity of the impeller inlet absolute velocity in the tangential direction; u1 and U2 respectively represent the inlet and outlet drag speeds of the impeller 5;

the rotational speed of the impeller 5 is unchanged, so the linking speeds U1 and U2 of the inlet and the outlet of the impeller 5 are unchanged; as shown in fig. 2 to 4, C1u is zero when no prerotation is performed, C1u is positive when positive prerotation is performed, C1u is negative when negative prerotation is performed, and C2u is determined by the blade angle and the slip factor at the outlet of the impeller 5, where it can be considered that the values are unchanged, so that the work load of negative prerotation is the largest, the work load of non-prerotation is centered, the work load of positive prerotation is the smallest, and the corresponding compressor characteristic line is shifted to the direction of small flow rate; specifically, the axial air intake is called no prewhirl, the deflection of the air flow to the rotation direction of the impeller 5 is called positive prewhirl, and the deflection of the air flow to the opposite direction of the rotation of the impeller 5 is called negative prewhirl; when the impeller 5 works in a low-flow state, the axial speed C1 is reduced to C1 ', the relative speed of the inlet of the impeller 5 is reduced to W1', the inlet attack angle is increased, and the increase of the attack angle leads to the increase of the load at the top of the blade and finally the surge phenomenon occurs; therefore, a backflow groove 6 is arranged between the inner casing and the outer casing, one end of the backflow groove 6 is connected with a wheel cover at the top of the blade, and the other end of the backflow groove 6 faces the air inlet end of the impeller 5, so that the kinetic energy of part of low-energy fluid in the impeller 5 is not enough to flow downstream and is converted into pressure, the backflow of the low-energy fluid is turned to the backflow groove 6, the through flow of the inlet of the impeller 5 is increased in a phase-changing manner, the attack angle of the blade is reduced, the load at the top of the blade is reduced; in addition, due to the rotation of the blades, the backflow gas has a part of tangential velocity, the amount of positive prerotation is increased after the backflow gas is mixed with the main flow, the flow is deviated to the direction of reduction, the working flow range of the high-speed centrifugal blower is effectively widened, and the working efficiency of the high-speed centrifugal blower is improved.

Example 2

Basically as in embodiment 1, preferably, the inner casing 2 is fixed in the outer casing 4 by a plurality of support plates 3, so that the connection relationship between the inner casing and the outer casing is relatively stable, and the inner casing and the outer casing are not easily separated due to the flow of high-speed fluid; more specifically, the support plate 3 is in a blade shape, so that the gas flow loss can be effectively reduced; in this embodiment, preferably, the number of the support plates 3 is 4-6, and the support plates 3 are circumferentially and uniformly distributed between the inner casing and the outer casing, and the too small number of the support plates 3 makes the connection between the inner casing and the outer casing unstable; too much amount suppresses the tangential velocity of the gas and creates a loss of gas flow.

Example 3

Basically the same as embodiment 1, different from embodiment 1, in this embodiment, the front end of the outer casing 4 is provided with an inlet guide vane 1; the air inlet flow channel of the outer casing 4 adopts a straight or slightly contracted form to reduce separation and flow loss, and the inlet guide vane 1 can rotate along a small shaft arranged at the root of the blade of the inlet guide vane 1 so as to adjust the outlet airflow angle of the inlet guide vane 1, namely the prerotation angle of the impeller 5; when the positive prerotation is adopted, the characteristic line of the unit deviates to the direction of small flow; the inlet guide vane 1 can adjust the prerotation amount of the inlet of the impeller 5, and when the positive prerotation is adopted, the flow of the blower can be correspondingly reduced; one end of the backflow groove 6 is connected with a wheel cover at the top of the blade, and the other end of the backflow groove faces between the inlet guide vane 1 and the air inlet end of the impeller 5, so that backflow gas can be collected with main flow gas behind the inlet guide vane 1; further, the inlet guide vane 1 is in an airfoil shape; the blade profile loss is reduced, and the inlet guide vane 1 is made of stainless steel; the wear resistance is strong, the strength is certain, and the service life of the inlet guide vane 1 is effectively prolonged;

the inlet guide vane 1 and the reflux groove 6 are combined, so that the comprehensive flow regulating capacity of the high-speed centrifugal blower can reach 50-110% of the design point flow; the stable working range of the high-speed centrifugal blower is widened, and meanwhile, higher efficiency is kept in the range; and the structure is simple, the control complexity is greatly reduced, the whole manufacturing cost is lower, and the device has great advantages. It is worth to be noted that the minimum working flow of the traditional centrifugal blower with the single adjustable inlet guide vane is about 70% of the flow of the design point, and the flow of the design point can reach 50% only by matching with the combined adjustment of the outlet guide vane; the utility model discloses make centrifugal blower can normally work under 50% design point flow, the flow control scope of blower unit is wide, simple structure simultaneously, low in manufacturing cost.

Example 4

Basically as in embodiment 1, preferably, the diffuser is a vaneless diffuser, which can reduce the fluid expansion loss, improve the working efficiency and has a simple structure, and the vaneless diffuser does not have the vibration phenomenon caused by the mutual interference between the blades and the impeller 5, so that the fatigue failure problem caused by the mutual vibration between the blades and the impeller does not exist, and the high-speed centrifugal blower has a wide working range; furthermore, the blade comprises a plurality of main blade bodies, a sub-blade body is arranged between every two adjacent main blade bodies, one end of the backflow groove 6 is connected with a wheel cover at the top of each main blade body, so that the working efficiency of the whole impeller 5 is high, and in a near-surge working condition, airflow at the position is led out to the inlet guide vane 1 and then flows back, and the load and the blocking condition at the blade tip of each main blade are reduced; in addition, the impeller 5 and the blades are made of aluminum alloy, so that the impeller is light in weight and meets certain working strength.

The examples of the utility model are only right the utility model discloses a preferred embodiment describes, and not right the utility model discloses design and scope are injectd, do not deviate from the utility model discloses under the prerequisite of design idea, the field engineering technical personnel are right the utility model discloses a various deformation and improvement that technical scheme made all should fall into the protection scope of the utility model.

Claims

1. The utility model provides a high-speed centrifugal blower, includes the spiral case, is provided with impeller (5) in the spiral case, and impeller (5) are connected with actuating mechanism, are provided with the blade on impeller (5), still are provided with diffuser, its characterized in that in the spiral case: the novel blade-mounted air conditioner is characterized by further comprising an outer casing (4), wherein the outer casing (4) is arranged on the air inlet side of the impeller (5), an inner casing (2) is arranged in the outer casing (4), a backflow groove (6) is arranged between the outer casing (4) and the inner casing (2), the backflow groove (6) is connected with a wheel cover at the top of the blade, and the other end of the backflow groove faces the air inlet end of the impeller (5).

2. A high-speed centrifugal blower as set forth in claim 1 wherein: the inner casing (2) is fixed in the outer casing (4) through a plurality of support plates (3).

3. A high-speed centrifugal blower as set forth in claim 2 wherein: the support plate (3) is blade-shaped.

4. A high-speed centrifugal blower as set forth in claim 3 wherein: the number of the support plates (3) is 4-6.

5. A high-speed centrifugal blower as set forth in claim 1 wherein: the front end of the outer casing (4) is provided with an inlet guide vane (1).

6. A high-speed centrifugal blower according to claim 5, wherein: the inlet guide vane (1) is made of stainless steel.

7. A high-speed centrifugal blower as set forth in claim 1 wherein: the diffuser is a vaneless diffuser.

8. A high-speed centrifugal blower as set forth in claim 1 wherein: the blade comprises a plurality of main blade bodies, a sub-blade body is arranged between every two adjacent main blade bodies, and one end of the backflow groove (6) is connected with a wheel cover at the top of each main blade body.

9. A high-speed centrifugal blower according to claim 1 or 8, wherein: the impeller (5) and the blades are made of aluminum alloy.