Turbocharger Compressor Work Round The Modal Analysis And Application

The title of this paper originates from "The Study of Locomotive Turbocharger Reliability Improvement", which is a scientific research development project of China Northern Locomotive and Rolling Stock Industrial Group. What described in this paper is the main work in the project. It is very realistic and applicable.The locomotive turbocharger is a kind of machine rotating in high speed. Being a critical part in the engine, it influences the performance and reliability of the diesel engine as well as the safe and punctual operation of the locomotive. Some model of turbochargers once had accidents of compressor working wheel (inducer and impeller) blade breaking in the course of operation on lines and made the locomotive break down. In this case, it is very important and urgent to diagnose the causes of the accidents and analyze the mode state.A large FEA program ANSYS5.7 (which is a module for mode state solution) is applied to analyze the vibration characteristics of the centrifugal compressor working wheels of the turbocharger. By the secondary development of ANSYS, a program of FEA automatic module setup and grid division has been edited for the compressor working wheels in ADPL language of ANSYS. This program is applicable for all working wheels of turbocharger compressors. It can be used to set the hexahedron grids which can be divided into different precisions on customers' requirements. The divided FEA grid module can be directly used for the calculation of strength and vibration frequencies of the compressor working wheels. This program solved the problems of difficult module setup in FEA calculation for centrifugal compressor working wheels, especially the difficult division of hexahedron grids. The calculation time and difficulty are greatly reduced and the program is therefore very applicable for engineering.The natural frequencies of the inducer blades, disks and impeller have been calculated. The natural frequencies and mode states are solved of the integral structure of the working wheels in static state and rotating state. The mode state is shown in color program and the vibration mode state is displayed in panorama. The disk resonance tolerance in operation is determined by analyzing its resonance program of Campbell. And then the breaking causes of the inducer glades are found out and finally an effective solution is proposed. The above calculations are quite coincident with the tests, which can be used for flexibility prediction in new designs. They are also the theoretical bases for failure analysis in operation.