Research On Failure Mechanisms For Compressor Components Based On Acoustic Resonance

During the past decades studies of aero-acoustic phenomena in turbomachinery were mainly carried out by research institutions. 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 lead to strong excitation sources, very little is known about the relevant physics, especially for centrifugal compressor. These were suspected to play a significant role in the root causes of the failures.In this paper, the failure mechanism of centrifugal compressor is researched based on several methods such as operational modal testing and modal computation, acoustic modes simulation, finite element method, sound intensity measurement, frequency analysis, etc. By using these methods, it can process simulation of acoustic modes, operational modal experiment and structural modal simulation analysis, pressure pulsation measurement, noise source identification.The specific tasks of this paper are as follows:(1) Noise source identification. Sound intensity measurement is the most effective method for localization noise source. The noise source of centrifugal compressor is investigated according to noise intensity measurement. The noise signals are obtained. Main characteristics of centrifugal compressor are investigated by analyzing the noise signal. Results show pipeline and cavity are major noise source. Noise source identification offer helps to pressure pulsation test and acoustic modes simulation.(2) Pressure pulsation test. Pressure pulsation is a major factor affecting the operational condition of compressor. Main characteristics of centrifugal compressor are investigated by analyzing the noise signal. Pressure pulsation are measured under different conditions. The results confirmed that vaned diffuser produce bigger pressure pulsation.(3) Acoustic modes simulation and verify. The frequencies of acoustic modes in a pipeline and compressor are calculated by theoretical analysis and numerical simulation. It is verified that pressure pulsation caused by acoustic modes impact on the pipeline structure. The natural frequencies of pipeline are analyzed by ANSYS. The vibration of pipeline is independent on structure modes. By Operational Modal testing of the centrifugal compressor, it is confirmed that the pressure pulsation generated independent on the dynamic characteristics of the structure of the compressor.There were few research on acoustic modes about compressor. The research is not only to extend the life of compressor components, to improve the vibration characteristics of compressor, but also has influence on the safety and reliability of compressor. The research will contribute to development for reduction of acoustic resonance on pipeline and centrifugal compressor based on acoustic resonance.