Tonal Noise Transmission through a Non-Axisymmetric Turbine OGV with Separated Flow: Prediction and Measurements

摘要

The transmission of sound through a Turbine Outlet Guide Vane (OGV) is investigated through numerical predictions and rig testing. Experimental vehicle consists of a state-of-the-art turbine stage and OGV that is noise tested in the CTA facility in Bilbao (Spain) under representative engine working conditions of Take-Off and Landing. Numerical predictions are performed using Mu~2s~2T, which is a second-order RANS method for hybrid grids. Unsteadiness of the flow is modelled as small perturbations using the frequency-domain Linearized RANS equations with 3D Unsteady Non-Reflecting Boundary conditions at the inlet/outlet of each domain. The OGV airfoils are non-equispaced, so that a 360° OGV simulation is required to get the acoustic characteristics to be compared with measurements. The acoustic transmission is also investigated in presence of extreme operating conditions in which the flow is separated from the OGV airfoil, and the capability of the linear methods for such operating conditions is evaluated.