Design method of axial flow type low-lift prepositioned inducer

Abstract

The invention provides a design method of an axial flow type low-lift prepositioned inducer. The inducer is suitable centrifugal pump units with medium-low specific speed which are widely used in the fields such as petrochemical industry, smelting industry and power plants. The invention gives a design formula for the main geometric size parameters of the inducer, wherein the parameters are as follows: the outer edge diameter of the inducer is D, the middle diameter of the hub of the inducer is Dh, the inlet edge inclining angle of a blade is alpha, the outlet edge outer edge diameter of the inducer is Do, the inducer hub conical angle of the inducer is theta, the radius of a wing type work surface of a flow surface A is Rp, a wing type outlet placing angle is beta and a wing type cord length is l. The flow field distribution at the inlet of the centrifugal pump can be improved by the low-lift prepositioned inducer, the centrifugal pump is suitable for the medium occasions containing solid particles, and the operation stability and suction performance of an impeller of the centrifugal pump are effectively improved under the condition of a low net positive suction head of the device.

Description

Technical field [0001] The patent of the present invention relates to a design method of an axial flow type low-lift front inducer, specifically, a design method of a front inducer suitable for improving the cavitation performance of a chemical centrifugal pump with a medium and low specific speed. Background technique [0002] The inducer is a blade type rotating machine used to increase the cavitation margin of the centrifugal pump impeller inlet device. It was first used in the aerospace field of engine fuel transfer pumps and other occasions. It has low blade load, small number of blades and suction performance Good and other characteristics can increase the medium pressure at the impeller inlet and effectively improve the cavitation at the impeller inlet of the centrifugal pump. With the expansion of various industrial applications, inducers are widely used in many low- and medium-speed centrifugal pump units in petrochemical, smelting, and power plants. The conventional in...

AI Technical Summary

Problems solved by technology

Conventional inducers mostly adopt a cylindrical helical axial surface structure, the blade distribution adopts a fixed pitch or variable pitch design, and the blade shape is mainly a flat structure. The size parameters of this inducer structure are easy to design, and the shape features are easy to manufacture and process. , but because the blade shape is too simple, the hydraulic efficiency and suction performance of the inducer itself are low, and there is a certain difference between the outlet flow field distribution and the design suction conditions of the centrifugal pump impeller, which has a certain impact on the suction performance of the impeller

In addition, because the flow channel of this type of inducer is long and the number of blades is large, it is easy to wear when conveying the medium containing solid particles, which easily causes the unstable operation of the centrifugal pump unit

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