Estimation of Turbine Noise Benefits Due to Acoustically Treated Outlet Guide Vanes

Authors

A. Serrano - ITP, Industria de Turbo Propulsores S.A., Spain
G. Torres - ITP, Industria de Turbo Propulsores S.A., Spain

Abstract

This paper aims to assess via CFD the feasibility of using acoustic treatments over the Outlet Guide Vanes (OGVs) surfaces in a turbine. The CFD solver to be used is Mu2 s 2T that is an in-house suite of codes. In absence of a dedicated experiment, the capability of Mu2 s 2T for assessing this novel technology is investigated in two parts. First, CFD predictions of turbine tones are compared with measurements for a state of the art turbine including OGV. Second, the CFD liner prediction capability is assessed in two test cases: straight duct with uniform flow and fan noise test with a lined OGV. Once the CFD capability is assessed and uncertainties understood, the treated OGV technology is investigated for a state of the art Low Pressure Turbine (LPT). The optimum liner characteristics are chosen by the construction of the usual cell depth vs porosity charts for a straight duct. Selected candidate is simulated over the suction or pressure OGV sides and the differences are discussed. Overall tone noise reduction deltas are provided and compared with existing technology consisting in having acoustic treatments over the hot nozzles downstream the OGV.