Aeroacoustic Phenomena In High Pressure Centrifugal Compressors - A Possible Root Cause For Impeller Failures.

Abstract

During the past decades studies of aeroacoustic phenomena in turbomachinery were mainly carried out by research institution. The aerospace industry was the main driver in this field since noise issues gained more and more significance. Though it has been known for some years that acoustic resonances may also lead to strong excitation sources, very little is known about the relevant physics, especially for centrifugal compressors. Failures that were observed in the field could not be explained by state-of-the-art analysis procedures, and it became from customer discussions that there is a strong need for better understanding of aeroacoustic excitation mechanisms; these were suspected to play a significant role in the root causes of failures. To improve the reliability of centrifugal compressors, especially for high-pressure applications, an extended in-house research program has been launched to better understand the involved interactions that may lead to machine failures. The current paper gives an overview on the research activities, presents the underlying theory, and gives new results that are relevant from a practical point of view. Anew aeroacoustic excitation model is presented and its successful application to explain tow impeller failures in the oil and gas industry is illustrated.