Research database

This proposal addresses the pressing issue of fan noise reduction in modern turbofan aircraft, focusing on the limitations of conventional acoustic liners in mitigating engine fan noise. The topic is particularly relevant in the context of Ultra High Bypass Ratio (UHBPR) engines, which displays lower Blade Passage Frequency (BPF) and higher broadband components, as well as limited installation space. The project includes two distinct yet interconnected lines of work. The first one, based on coupling high-fidelity Lattice-Boltzmann Very Large Eddy Simulation (LBM-VLES) with experiments of acoustic liners manufactured with different techniques, aims at assessing the impact of the facesheet orifice geometrical features and manufacturing uncertainty on the measured impedance. The second line of work involves the innovation of experimental impedance eduction methods to better account for the impact on the liner impedance due to variations of particle velocity and flow profile over the sample surface. Finally, the proposed project seeks the development of tools that will enable the design of novel liners taking in account computational and experimental insights. The proposal is outlined in the subsequent sections encompassing the research’s methodology, proposed timeline, and budget considerations.