Abstract: The change laws of multi-field load and stress response of turbocharger centrifugal compressor impeller are studied for the static strength failure of impeller in a variable altitude environment. The unidirectional steady-state fluid-structure interaction method is used to calculate the single-field stress and multi-field coupling stress of impeller under aerodynamic, thermal, and centrifugal loads. The results indicate that, when only the inlet pressure and inlet temperature are changed according to the altitude without changing the true flow rate and the true revolving speed, the flow angle at impeller inlet increases with altitude, resulting in a larger static pressure difference on the leading edge of the long blade; and the maximum aerodynamic stress is then transferred from the trailing edge to the leading edge of the long blade. In the same case, the thermal load, thermal stress and maximum coupling stress decrease with altitude. When the working conditions of the supercharged engine remain unchanged, with the increase in altitude， the absolute changes in the aerodynamic and thermal stresses of the impeller are small, and the increase in the compressor speed brings a large increase in the centrifugal stress, which in turn leads to an increase in coupling stress.

Key words: turbocharger, variablealtitude, centrifugalcompressorimpeller, multi-fieldcoupling, stressanalysis