CN112628191A

CN112628191A - Axial flow pump for inhibiting radial flow of swept blades

Info

Publication number: CN112628191A
Application number: CN202011509467.0A
Authority: CN
Inventors: 潘强; 张德胜; 施卫东; 赵睿杰
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2021-04-09
Anticipated expiration: 2040-12-18
Also published as: CN112628191B

Abstract

The invention provides an axial flow pump for inhibiting radial flow of swept blades, which comprises an impeller hub, impeller blades and a guide cap. The impeller blades and the guide cap are fixed on the impeller hub, and the front edges of the impeller blades are provided with a plurality of channels. The cross section of the channel is semicircular, the axes of the channel are distributed along the circumferential direction, and the channel is transited from one side of the front edge of the blade, which is close to the pressure surface, to one side of the suction surface. The invention has the advantages that when radial flow is generated and passes through the channel, the incoming flow at the front edge of the blade extrudes the radial flow to enable the radial flow to enter the channel, and the fixed wall surface of the channel generates stronger constraint on the liquid flow, thereby achieving the effect of weakening or eliminating the radial flow.

Description

Axial flow pump for inhibiting radial flow of swept blades

Technical Field

The invention relates to the technical field of fluid machinery, in particular to an axial flow pump capable of inhibiting radial flow of swept blades.

Background

The traditional axial flow pump has large flow, low lift and high efficiency, and is widely applied to various large water conservancy hubs in China due to small volume and low construction cost. In order to improve the passing safety of aquatic organisms (fish, shrimp and the like) which are not considered in the traditional design, the biological damage can be effectively reduced by thickening and bending the front edge of the blade to form a spiral inlet. However, the thickened leading edge of the spiral vane causes increased radial flow of the fluid, which adversely affects pump efficiency and cavitation performance. To avoid this, the geometry of the leading edge needs to be adjusted to reduce or even eliminate the radial flow tendency of the flow.

Disclosure of Invention

The invention provides an axial flow pump for inhibiting radial flow of a swept blade, aiming at the problem that the radial flow of the swept blade of the axial flow pump is easy to generate at the front edge.

In order to realize the purpose, the invention adopts the technical scheme that: an axial flow pump for inhibiting radial flow of swept blades comprises an impeller hub, wherein a plurality of impeller blades are arranged on the impeller hub, the front edges of the blades on the impeller blades are bent towards the rotating direction of the impeller blades or the opposite direction of the rotating direction, and a plurality of channels are arranged on the front edges of the blades.

In the scheme, the axes of the channels are distributed along the circumferential direction and are transited from the side, close to the pressure surface, of the front edge of the blade to the side, close to the suction surface, of the blade.

In the scheme, the distance L between the axes of two adjacent channels, the sweep angle beta and the outer diameter D of the impeller satisfy the following relation:

in the above scheme, the cross section of the channel 6 is semicircular.

In the above solution, the radius R of the semicircular section remains constant in the same channel; for channels at different radii, the radius R of the semicircular cross-section depends on the leading edge thickness h and satisfies the relationship:

0.05h≤R≤0.15h。

the invention has the beneficial effects that: when the liquid flow approaches to the front edge of the blade, the liquid flow has a radial flow tendency due to the swept front edge, when the radial flow passes through the channel, the incoming flow of the front edge along the circumferential direction can extrude the radial flow to enter the channel, and the fixed wall surface of the channel can generate strong restraint on the liquid flow to keep the axial and circumferential movement of the liquid flow, so that the effect of reducing or eliminating the radial flow is achieved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiment or the prior art will be briefly described below.

Fig. 1 is a three-dimensional schematic diagram of a channel for inhibiting radial flow of swept blades of an axial flow pump provided by the invention.

Figure 2 is a partial top view of a channel provided by the present invention.

Figure 3 is a cross-sectional view of a channel a-a provided by the present invention.

Figure 4 is a cross-sectional view of a channel B-B provided by the present invention.

In the figure: 1-rotating shaft, 2-impeller hub, 3-impeller blade, 4-blade rim, 5-blade leading edge, 6-channel, 7-guide cap, 8-pressure surface and 9-suction surface.

Detailed Description

The invention will be further described with reference to the following drawings and specific examples:

the present invention provides an axial flow pump for inhibiting radial flow of swept blades, as shown in fig. 1. The impeller blades 3 are generally two and symmetrically fixed on the impeller hub 2, and the flow guiding cap 7 is streamlined and fixed on the impeller hub 2 to provide uniform incoming flow for the impeller blades 3.

The sweep of the axial flow pump blades is defined as: the blade leading edge 5 bends forward in the rotating direction, and at the moment, the included angle alpha formed by the blade rim 4 and the blade leading edge 5 is smaller than 90 degrees, as shown in fig. 2; the front edge 5 of the blade bends to be sweepback in the opposite direction of rotation, and at the moment, the included angle alpha formed by the rim 4 of the blade and the front edge 5 of the blade is more than 90 degrees;

fig. 2 is a partial top view of the channel 6, here exemplified by a forward swept blade leading edge 5, when the angle a is less than 90 degrees. In order to restrain radial flow generated by the curved and swept blade leading edge, a plurality of grooves 6 are arranged on the leading edge, the grooves 6 are positioned on the surface of the blade leading edge 5 and are inwards concave, the axes of the grooves 6 are distributed along the circumferential direction, and the distance L between the axes of the adjacent grooves and the curved and swept angle beta and the outer diameter D of the impeller satisfy the following relation:

fig. 3 is an expanded view of the channel 6 in section a-a, and fig. 4 is an expanded view of the channel 6 in section B-B, and it can be seen from the two views that the section of the channel 6 is semicircular. The radius R of the semicircular cross-section remains constant in the same channel, i.e. the cross-sectional area remains constant as it transitions from the end of the leading edge of the blade that is closer to the pressure surface 8 to the end that is closer to the suction surface 9.

For channels at different radii, the radius of the semicircular cross-section depends on the leading edge thickness h and satisfies the relationship:

0.05h≤R≤0.15h

according to the axial flow pump for inhibiting radial flow of the swept blade, the plurality of channels 6 are arranged on the front edge of the blade, so that the resistance of radial flow of liquid flow can be increased, and the wall surfaces of the channels restrict the liquid flow to move along the axial direction and the circumferential direction, so that the purpose of weakening the radial flow is achieved.

Claims

1. The axial flow pump for inhibiting radial flow of the swept blades is characterized by comprising an impeller hub (2), wherein a plurality of impeller blades (3) are arranged on the impeller hub (2), the front edges (5) of the impeller blades (3) are bent towards the rotating direction of the impeller blades (3) or the opposite direction of the rotating direction, and a plurality of grooves (6) are arranged on the front edges (5).

2. An axial flow pump for suppressing radial flow in swept blades according to claim 1, wherein the axes of the channels (6) are distributed in the circumferential direction, transitioning from the pressure side to the suction side of the leading edge of the blade.

3. An axial flow pump for suppressing radial flow of swept blades according to claim 1, wherein the distance L between the axes of two adjacent channels (6), the sweep angle β and the impeller outer diameter D satisfy the relationship:

4. an axial flow pump for suppressing swept blade radial flow according to claim 1, wherein the channels (6) are semi-circular in cross-section.

5. An axial flow pump for suppressing swept blade radial flow according to claim 4, wherein the radius R of the semi-circular cross section remains constant in the same channel; for channels at different radii, the radius R of the semicircular cross-section depends on the leading edge thickness h and satisfies the relationship: r is more than or equal to 0.05h and less than or equal to 0.15 h.