Computational Analysis of Passive Acoustic Liner Techniques for Jet and Compressor Noise Reduction

The growing expansion of commercial aviation has intensified the need for effective noise mitigation strategies in aircraft propulsion systems. Broadband jet noise and tonal compressor noise remain significant contributors to overall aircraft acoustic emissions. This study investigates passive aeroacoustic control techniques aimed at reducing such noise sources through numerical modeling and parametric analysis.

A computational framework based on the Transference Matrix Method (TMM) combined with acoustic impedance modeling is employed to evaluate the sound absorption and transmission characteristics of perforated and microporous liner materials. The acoustic performance is analyzed over a frequency range of 100 Hz to 5000 Hz. Key geometric parameters, including porosity, hole diameter, and cavity depth, are systematically varied to determine their influence on attenuation efficiency under representative operating conditions.

The simulation results indicate that microporous liners exhibit improved absorption capability and a more uniform frequency response compared to conventional perforated liners, particularly within the mid- and high-frequency bands where compressor tonal components are dominant. An optimized configuration with 5% porosity and a hole diameter of 1 mm achieves a maximum transmission loss of approximately 18 dB within the evaluated frequency spectrum.

The findings provide a structured computational approach for the early-stage design and optimization of passive acoustic liners in modern turbofan compressor systems. This study supports the integration of advanced liner configurations to enhance noise reduction performance in aerospace propulsion applications.