Development of a novel grazing flow test rig for acoustic liners’ assessment

This research activity addresses the development of a test bench for acoustic measurements in a thermally hostile environment, representative of the exhaust in an aircraft engine, for liner characterization purposes. In this regard, a brand-new rig at the Department of Industrial Engineering (DIEF) of the University of Florence (UniFI) was designed and is introduced in detail. The design of this experimental asset, which would be the combination of a high-speed wind tunnel and an acoustic test rig, has been carefully addressed. The rig is presented and its capability to support reliable acoustic tests is preliminarily verified. The impedance of a liner sample is assessed by means of a data reduction process, considering both a 2D and a 3D incoming acoustic field inside the test-section. Results are promising and show the capability of the developed rig to achieve reliable acoustic information in a defined frequency band.