Blade Vibration Measurement and Numerical Analysis of a Mistuned Industrial Impeller in a Single-Stage Centrifugal Compressor

Abstract Understanding and predicting the dynamical behavior of the impeller structure under realistic condition is vital for resonance-free and reliability design. This paper presents a novel method for high fidelity measurement and efficient modeling of impeller blade vibration considering realistic operating environment and mistuning effect. To clarify the blade forced vibration, strain gauge and blade tip timing (BTT) measurement have been conducted. Measurement introduced mistuning and flow disturbance from strain gauges are further excluded with tip-timing. The blade mistuning is then identified and quantified with the help of parameter estimation method and updates the numerical mistuned forced response model. Aerodynamic forcing function due to downstream diffuser vanes is also numerically evaluated based on a decoupled two row configuration and time transformation method. Results shown that BTT system is well applied to capture the blade resonance response and shows a promising way for monitoring individual blade component. The aerodynamic forcing is also found to be well captured and presents a wave decay trend along the flow path towards the upstream. Finally, based on the proposed BTT parameter driven vibration prediction method, the blade mistuned forced response shows a good agreement with measurement results. Improvement also implies variations of parameters and mistuning pattern should be considered as a critical part and uncertainty source in the numerical prediction. This work is of scientific significance to enrich the knowledge of blade vibration in centrifugal compressor using tip-timing and of industrial application value to consider mistuning problems with efficient reduce-order modeling method.