CFD Analysis of a Gas Turbine Engine Test Cell to Understand and Alleviate Infrasound
Gas turbine engines often pass through tests in enclosed test facilities. One problem that arises during these tests is the infrasound phenomenon. Infrasound can be a problem for many reasons, ranging from rattling windows to structural damage to the test cell. The aim of this paper is to understand the cause of severe infrasound experienced at Honeywell Aerospace and to evaluate and select a solution using advanced Computational Fluid Dynamics (CFD) techniques. These CFD simulations modeled an entire test cell with an engine in place, which is a more complete approach than what is reported in the literature. The DES turbulence model was applied in a transient, compressible, turbulent simulation in order to capture small pressure fluctuations. Test data taken using an engine/test cell configuration that does not cause problems was used to successfully validate the CFD approach. It was found that the narrow, high-velocity exhaust plume examined in this study impacted the convex blast plate in the aft portion of the test cell having diffused only slightly. The exhaust then rebounded and buffeted the plume, causing extreme dynamic loading. Through a modification to the blast basket, it was shown that the problem would be alleviated and sound pressure levels in the test cell would be reduced by 5 to 32 dB, depending on location in the test cell.