Instability detection of centrifugal compressors by means of acoustic measurements

Abstract Preventing the compressor from instability phenomena is of great importance for the safe operation of many industrial products, such as aero-engines. Hence, a simple and low-cost method is extremely demanded to detect instability phenomena of compressors, especially in the real operating environment, and acoustic measurement is an alternative solution. In this paper, dynamic pressure and acoustic characteristic of a centrifugal compressor are experimentally investigated. First, all typical operation conditions of the compressor are illustrated and all instability phenomena that occur within the compressor are identified. Then, dynamic pressure is analyzed to present characteristics of different instability phenomena. Finally, the ability of acoustic measurement to detect instability phenomena is discussed with detailed analysis on acoustic signals, and guidelines for instability detection by means of acoustic measurement are established. Results show that four instability phenomena, rotating instability, rotating stall, mild surge and deep surge, occur within the compressor. In addition, the acoustic sensor is recommended to be installed near the compressor casing, and the acoustic signal can detect the rotating stall, the mild surge and the deep surge by capturing their characteristic frequency. This paper demonstrates the ability to capture instability phenomena via acoustic signals and provides an acoustic measurement technology to detect instabilities at any time of the full life cycle of a compressor.