Computational Modeling and Validation Testing of Dynamic Blade Stresses in a Rotating Centrifugal Compressor Using a Time Domain Coupled Fluid-Structure Computational Model

Abstract

This work develops a time domain coupled fluid-structure computational model that predicts dynamic blade stresses in a rotating centrifugal compressor. Although, much research has been performed on axial flow turbomachinery, little has been published for radial machines such as centrifugal compressors and radial inflow turbines. This research develops a time domain coupled fluid-structure computational model using commercially available codes. The model couples the codes unidirectionally, where pressures are transferred to the structural code during the transient solution, and the fluid mesh remains unaffected by the structural displacements. Models are developed for the compressor at blade resonant conditions. The model is then validated with a rotating test of a centrifugal compressor instrumented with blade mounted strain gauges. The test rig is an open loop rig that utilizes an unshrouded centrifugal compressor with a vaneless diffuser. The strain gauge signals are passed through a high gain, low noise amplifier that is mounted on the compressor rotor. This work not only develops a unidirectionally coupled fluid-structure model capable of predicting dynamic strains, but also provides valuable experimental data that can be used for future research and validation cases of fluid-structure interaction (FSI) models.