Effect of Operational Temperature on Contact Dynamics of Shrink-Fitted Compressor Impeller Joint

Abstract

In this paper, the contact behavior of a shrink-fitted joint in a rotor assembly at different spin speeds using the three-dimensional solid finite element approach with inclusion of thermal expansion effect is studied. A custom contact model is utilized for shrink-fitted joint analysis under centrifugal and thermal loads. Theory for applying the nodal temperature to the thermal expansion force vector for three-dimensional finite elements is presented and implemented. Shrink-fitted conical impeller rotor assembly is studied, and the results are presented in Campbell diagram form. The reduction of the interference of the shrink-fitted joint due to centrifugal and thermal forces at high-speed operation as well as the contact status are updated at each rotational speed step. Based on the results presented in this paper, the thermal expansion force will have an effect on the natural frequencies of the rotor system.