Multi Field Coupling Stress Calculation and Analysis of CentrifugalCompressor Impeller Under Different Atmospheric Conditions

Abstract

To improve the power density, air pressurization systems are widely used in vehicle internal combustion engines, hybrid engines and fuel cell engines. Centrifugal compressor is the core component of air pressurization system. It’s aerodynamic and reliability performance is the key to the whole system design. The atmospheric environment has great influence on the performance and reliability of the centrifugal compressor. When the atmospheric environment changes, unexpected failures may happen to the compressor impeller, affecting the reliability of vehicle engine. Aiming at a centrifugal compressor impeller of turbocharger for diesel engine, the multi field coupling stress under different atmospheric conditions is studied, and the key influencing factors of impeller stress are analyzed. Based on experimental tests, the working conditions of the centrifugal compressor for turbocharged diesel engine operating as external characteristics are obtained. By establishing a numerical calculation model of multi field coupling stress, and applying BKIN model to the material, the variation law of impeller stress with atmospheric environment is analyzed in the range of elastic-plastic mechanics. The results show that the centrifugal stress is always the major component of the coupling stress and the high coupling stress region of the investigated impeller appears in the shaft hole near the rear face. The results could provide reliability design strategies for solving the problem of impeller strength under different atmospheric conditions and for structural optimization.