RU2550564C2 - Centrifugal pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to pump building and can be used in turbo-pump units of aircraft and missile engineering. A centrifugal pump includes housing 1, inside which there arranged on shaft 2 is centrifugal wheel 3 with groove seals 4 and passages 5 for bypass of leakages to inlet zone 6 of wheel 3 and disc fairing 7 with blade grid 10 on the side of passages 5 for bypass of leakages. In disc fairing 7 there is receiving annular cavity 8, profile 9 of which opposite passages 5 for bypass of leakages is smoothly bent in direction of the inlet of inter-blade passages of blade grid 10. Location radius of passages 5 for bypass is less than radius of leading edges of blade grid 10 of disc fairing 7. Such design fully excludes negative turbulent influence of leakages on liquid flow in the inlet zone of the centrifugal wheel, forms optimum leakage flow along the main flow and the rear disc of the centrifugal wheel.

EFFECT: invention is aimed at full elimination of negative influence of leakages and increase of suction capacity of a centrifugal pump.

1 dwg

Description

The invention relates to a pump engineering and can be used in turbopump units of aviation and rocket technology.

Energy losses occur in the pump due to leakage of fluid from the high-pressure cavity to the low-pressure cavity through gap, floating, or labyrinth seals.

There are two well-known schemes for eliminating these leaks:

- leaks are diverted to the pump inlet, which is associated with the need to introduce additional external structural elements (a bypass pipe with adjusting hydraulic resistance) (see, for example, “Low-flow pumps of aviation and space systems”, M.V. Kraev, V. A. Lukin , B.V. Ovsyannikov, M.: Mechanical Engineering, 1985, p. 90, Fig. 6.1);

- leaks are introduced into the inlet zone of the centrifugal wheel through the holes in the rear wheel disc, which significantly simplifies the design of the pump (see, for example, “High-speed vane pumps”, edited by B.V. Ovsyannikov and V.F. Chebaevsky, M .: Mechanical Engineering , 1975, p.209, Fig. 3.46, as well as a description of the USSR copyright certificate No. 1771248, F04D 29/04, 1988).

The disadvantage of this leakage rejection scheme is their harmful effect on the fluid flow in the centrifugal wheel: the oncoming leakage flow turbulizes the main fluid flow in the inlet zone of the centrifugal wheel, which reduces its suction capacity.

Also known is a centrifugal pump, taken as a prototype of the invention, in which from the side of the leakage bypass channels in the input zone of the centrifugal wheel, a disk cowl (annular shield) is installed on the shaft, on which a spatula (additional blades) is made opposite the leakage bypass channels (see copyright certificate) USSR No. 1143884, F04D 29/22, F04D 29/66, 1985).

The disadvantage of the prototype is the incomplete elimination of the harmful effects of leaks on the fluid flow in the centrifugal wheel: the conical leak flow cuts and turbulizes the main fluid flow in the inlet zone of the centrifugal wheel, which reduces its suction capacity. In addition, the discharge of leaks directly into the scaffold is accompanied by an increase in the fluid pressure behind and in front of the hub of the centrifugal wheel. It also reduces the efficiency of the scapular lattice in improving the anti-cavitation qualities of the centrifugal wheel, leading to an imbalance in the axial forces acting on the centrifugal wheel.

The invention is aimed at completely eliminating the harmful effects of leaks and increasing the suction capacity of a centrifugal pump.

To do this, in a centrifugal pump containing a housing, inside of which a centrifugal wheel with seals and leakage bypass channels to the inlet zone of the centrifugal wheel and a disk cowl with a spatula lattice on the side of the leakage bypass channels, unlike the prototype, is located in the disk cowl on the side of the channels leakage bypass has a receiving annular cavity, the profile of which opposite the bypass channels is smoothly curved in the direction of entry into the interscapular channels of the scapular lattice, and the channel erepuska made smaller than the radius of the input edges of the grating disk blade shroud.

This design completely eliminates the harmful effects of leaks on the fluid flow in the inlet zone of the centrifugal wheel, and forms the optimal laminar flow of leaks in the direction of the main fluid flow along the rear disc of the centrifugal wheel, which increases the suction capacity of the pump.

The invention is illustrated in the drawing, which shows a diagram of a centrifugal pump.

The centrifugal pump comprises a housing 1, inside of which a centrifugal wheel 3 is placed on the shaft 2, slotted seals 4 of the centrifugal wheel and leakage bypass channels 5 to the inlet zone 6 of the centrifugal wheel. From the side of the leakage bypass channels 5, in the input zone 6 of the centrifugal wheel 3, a disk fairing 7 is installed on the shaft 2, in which a receiving annular cavity 8 is made opposite the bypass channels 5 and a blade grill is made on the periphery, while the profile of the receiving cavity 9 opposite the bypass channels is smoothly curved in the direction of entry into the interscapular channels of the blade grid 10, and the radius of the bypass channels R _{Kp is} made smaller than the radius of the input edges R _I blade lattice disk cowl.

During the operation of the centrifugal pump, the working fluid enters the inlet zone 6, wheel 3 and then into the cochlea housing 1. At the same time, part of the fluid flows through the slotted seal 4 and the leakage bypass channels 5 into the profiled receiving annular cavity 8 of the fairing 7, where it is formed by the profile 9 and blade spatula 10 fairing 7 into the laminar flow of fluid at the entrance to the centrifugal wheel 3.

The use of the invention eliminates the turbulization of the flow of the working fluid in front of the centrifugal wheel by leaks, realizes the fully useful use of the energy of the leakages of the working fluid, and, ultimately, increases the suction capacity of the centrifugal pump.

Claims (1)

A centrifugal pump comprising a housing, inside of which a centrifugal wheel with seals and leakage bypass channels to the inlet zone of the centrifugal wheel and a disk cowl with a spatula grill on the side of the leakage bypass channels, characterized in that in it, in the disk cowl, on the side of the channels the bypass has a receiving annular cavity, the profile of which opposite the bypass channels is smoothly curved in the direction of entry into the interscapular channels of the scapular lattice, while the radius of the bypass channels and made smaller than the radius of the input edges of the blade grating disk fairing.