Investigation on the acoustic interaction between over-the-stator liner and stator blade row

To investigate the noise reduction characteristics of a liner located at the blade tip on incident sound waves, this study combines experimental and numerical methods to explore the acoustic interaction mechanism between incident sound waves, the over-the-stator liner (OTSL), and the blade row under flow-free conditions. Experimental comparisons among the OTSL (with blade row), the liner only (no blade row), and the blade row only (with a hard wall casing) configurations reveal that the blade row significantly affects the liner’s noise reduction performance, and the OTSL exhibits effective sound absorption for both transmitted and scattered sound waves. Overall, the noise reduction effectiveness of the OTSL is superior to that of the liner only. Numerical analyses of acoustic particle velocity on the liner surface and pressure fluctuations on the blade surface confirm that the interaction between the OTSL and the blade row influences the liner’s dissipative characteristics and the blade row’s scattering behavior. Further investigations indicate that this interaction is correlated with the sound wave propagation direction, frequency, blade angle, and the sound absorption performance of the liner itself.