CN106996389B

CN106996389B - Short-distance inducer without blade top clearance cavitation

Info

Publication number: CN106996389B
Application number: CN201710382456.2A
Authority: CN
Inventors: 朱国俊; 罗兴锜; 冯建军; 吴广宽
Original assignee: Xian University of Technology
Current assignee: Xian University of Technology
Priority date: 2017-05-26
Filing date: 2017-05-26
Publication date: 2020-06-26
Anticipated expiration: 2037-05-26
Also published as: CN106996389A

Abstract

The invention discloses a short-distance inducer without blade top gap cavitation, which comprises an inducer wheel hub body, wherein a circle of axial flow type blades are uniformly distributed along the circumferential direction of the inducer wheel hub body, the outer edge of each axial flow type blade is coaxially provided with a wheel rim ring sleeve, the axial flow type blades are fixedly connected with the inner surface of the wheel rim ring sleeve into a whole, and one end part of the inducer wheel hub body, which is close to a pump inlet, is provided with a locking nut. The problems of blade top gap cavitation erosion and blade top gap leakage flow in the operation process of the existing inducer are solved.

Description

Short-distance inducer without blade top clearance cavitation

Technical Field

The invention belongs to the technical field of fluid machinery and engineering equipment, and relates to a short-distance inducer without blade top clearance cavitation.

Background

The inducer belongs to an axial flow impeller and is usually arranged at the inlet of a pump impeller for increasing the inlet pressure of the pump so as to improve the cavitation performance of the pump. The inducer usually adopts a spiral impeller, and a blade top gap exists between the inducer and the pump inlet shell. Due to the existence of the blade top gap, gap cavitation is easily generated when fluid at the wheel edge of the inducer flows around the blade top gap at a high speed under the action of the front-back pressure difference, and the blade at the wheel edge of the inducer is cracked and notched under the cavitation action induced by the blade top gap cavitation, so that the performance of the inducer is reduced, and further the cavitation of the centrifugal pump behind the inducer is caused, and the phenomenon is particularly obvious in certain small-sized high-speed pumps (such as vehicle-mounted fire pumps).

Disclosure of Invention

The invention aims to provide a short-distance inducer without blade top gap cavitation, which solves the problems of blade top gap cavitation erosion and blade top gap leakage flow in the operation process of the existing inducer.

The invention adopts the technical scheme that the short-distance inducer without the blade top gap cavitation comprises an inducer wheel hub body, wherein a circle of axial flow type blades are uniformly distributed along the circumferential direction of the inducer wheel hub body, the outer edges of the axial flow type blades are coaxially provided with a wheel rim ring sleeve, the axial flow type blades are fixedly connected with the inner surface of the wheel rim ring sleeve into a whole, and one end part of the inducer wheel hub body, which is close to a pump inlet, is provided with a locking nut.

The present invention is also characterized in that,

wherein the number of the axial flow type blades is not less than 3.

Wherein the outer surface of the rim ring sleeve is provided with continuous spiral labyrinth seal teeth.

Wherein the tooth profile of the spiral labyrinth seal tooth is rectangular.

Wherein the precession direction of the spiral labyrinth seal tooth is as follows: the screw-in is carried out from the inlet to the outlet of the inducer in the direction opposite to the rotating direction of the inducer.

Wherein the lock nut is cone-shaped or hemispherical.

The invention has the beneficial effects that the inducer disclosed by the invention adopts the axial flow pump blades with short axial distance, so that the whole inducer has a compact structure and is easy to arrange. Meanwhile, the inducer has no blade top gap, so that gap cavitation can not be generated, the inducer is protected from being damaged by blade top gap cavitation, the service life of the inducer is prolonged, the negative influence of gap leakage flow on the lift of the inducer is eliminated, and effective guarantee is provided for the stable and safe operation of an impeller behind the inducer.

Drawings

FIG. 1 is a schematic structural diagram of a short-range inducer without tip clearance cavitation according to the present invention;

FIG. 2 is a schematic structural diagram of a short-distance inducer without blade top clearance cavitation of the invention installed on a water pump.

In the figure, 1, an inducer hub body, 2, an axial flow type blade, 3, a rim ring sleeve, 4, a locking nut, 5, a rotating shaft, 6, a pump inlet shell and 7, a water pump body.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention relates to a short-distance inducer without tip clearance cavitation, which is structurally shown in figure 1 and comprises an inducer wheel hub body 1, wherein a circle of axial flow type blades 2 are uniformly distributed along the circumferential direction of the inducer wheel hub body 1 (at the same axial position), the outer edges of the axial flow type blades 2 are coaxially provided with a wheel rim ring sleeve 3, the axial flow type blades 2 are fixedly connected with the inner surface of the wheel rim ring sleeve 3 into a whole, and one end part of the inducer wheel hub body 1, which is close to a pump inlet, is provided with a locking nut 4.

Wherein the number of axial flow blades 2 is not less than 3.

Wherein the outer surface of the rim ring sleeve 3 is provided with continuous spiral labyrinth seal teeth.

Wherein the tooth profile of the spiral labyrinth seal tooth is rectangular.

Wherein the lock nut 4 is cone-shaped or hemispherical.

When the short-distance inducer without the blade top gap cavitation is installed on the pump body 7, as shown in fig. 2, an inducer hub body 1 is installed on a rotating shaft 5 through key connection and then locked by a locking nut 4 (a threaded hole is formed in the center of the locking nut 4, an external thread is arranged at the end part of the rotating shaft 5, the rotating shaft 5 is connected with the locking thread 4 through the thread, and the locking nut 4 plays a role in positioning the inducer hub body 1 on the rotating shaft 5 and also plays a role in guiding flow).

According to the short-distance inducer without the blade top gap cavitation, the axial flow type blades 2 with short axial distance are arranged on the inducer hub body 2, so that the axial size of the whole inducer is shortened. Then, a circle of annular rim ring sleeve 3 which is fixedly connected with the axial flow type blades 2 into a whole is arranged on the outer edges of the axial flow type blades 2, so that blade top gaps of the inducer are eliminated, water flow does not generate gap cavitation when passing through the inducer, the service life of the inducer is prolonged, and the negative influence of blade top gap leakage flow on the lift of the inducer is eliminated. Radial and axial gaps exist between the rim ring sleeve 3 and the pump inlet shell 6, and when the inducer rotates, the spiral labyrinth seal teeth on the outer surface of the rim ring sleeve 3 generate a pumping effect on fluid in the radial gap between the outer surface of the rim ring sleeve 3 and the pump inlet shell 6, so that the fluid obtains pumping pressure energy, the pressure difference which promotes the fluid to generate leakage in the radial gap is offset, the fluid leakage is prevented, and a good sealing effect is achieved.

The short-distance inducer without the blade top gap cavitation eliminates the phenomenon of blade top gap cavitation erosion in the operation process of a conventional inducer, protects the inducer from being damaged by the blade top gap cavitation erosion, eliminates the negative influence of the blade top gap leakage flow on the lift of the inducer, and can ensure the stable and safe operation of an impeller behind the inducer.

Claims

1. A short-distance inducer without blade top clearance cavitation is characterized in that: the induction wheel hub comprises an induction wheel hub body (1), a circle of axial flow type blades (2) are uniformly distributed along the circumferential direction of the induction wheel hub body (1), a rim ring sleeve (3) is coaxially arranged on the outer edge of each axial flow type blade (2), the axial flow type blades (2) are fixedly connected with the inner surface of the rim ring sleeve (3) into a whole, and a locking nut (4) is arranged at one end part, close to a pump inlet, of the induction wheel hub body (1); the outer surface of the rim ring sleeve (3) is provided with continuous spiral labyrinth seal teeth, the tooth form of each spiral labyrinth seal tooth is rectangular, and the precession direction of each spiral labyrinth seal tooth is as follows: and the inducer rotates from the inlet to the outlet of the inducer in the direction opposite to the rotating direction of the inducer.

2. The short-range inducer of bladeless interstitial cavitation according to claim 1, wherein: the number of the axial flow type blades (2) is not less than 3.

3. The short-range inducer of bladeless interstitial cavitation according to claim 1, wherein: the locking nut (4) is conical or hemispherical.