Structural optimization design of connection between centrifugal impeller and shaft end based on finite element method

Abstract

A centrifugal compressor is the core equipment of the chemical industry. To solve the problems of assembly difficulties and poor mechanical properties caused by the connection between impeller and shaft end in existing compressor, this paper takes a small geared air compressor designed by Shenyang Borui Turbine Technical Service Co., Ltd. as an example and designs its first-stage impeller and shaft end into three structural forms of tie rod–pin connection, tie rod–end key connection, and flange connection, respectively, to find an optimal connection mode between the centrifugal impeller and shaft end. Firstly, the calculation method is verified. Then, the stress, strain, deformation, and critical rotor speed of these three structures are compared and analyzed based on multi-parameter genetic optimization method. The results show that when the impeller and shaft end are connected by the tie rod–end key structure, compared to the tie rod–pin connection structure and flange connection structure, the maximum stress is reduced by 43.8% and 61.2%, the strain is reduced by 43.8% and 61.8%, the deformation is reduced by 3.64 times and 6.27 times, respectively, and the resonance margin will also be greatly improved. The research results in this paper provide a theoretical basis for the reliable design of the connection between the centrifugal impeller and shaft end.