Additive manufacturing of ceramic acoustic liners for aircraft noise reduction

Abstract

Noise pollution in large cities has significantly increased in the last couple of years. The rise of air traffic and electric air taxis will not delay this growth. Solutions to address the large amounts of noise from turbofan engines are to place honeycomb sound absorbers made of stainless and aluminum. The location of the acoustic liners is around the inlet to the combustion chamber. The problem with the current method is that these sound absorbers cannot withstand high temperatures and high pressures. An alternate solution is to place fiberglass blankets on the inlet, but they can potentially block airflow. This paper investigates an inexpensive method to 3D print ceramic porous structures for noise reduction using a modified extrusion 3D printer. Our solution aims to minimize cost, design complex geometries, expand scalability, and use ceramic characteristics to withstand harsh environments on the engines. With a modified version of the Delta WASP 2040 Clay, sound absorbers are 3D printed with clay-based materials. The samples are tested using a two-microphone normal incidence impedance tube for acoustic properties. Our work shows a potential low-cost alternative with 3D printed clay-based ceramics in the future of acoustic liners.