Numerical Solution of the Flow around a Turbofan and its Wind Tunnel Simulator

Kurzfassung

In the process of aircraft development the main tasks of engine integration have changed with the progress of aircraft and engines. The interference effects of turbofan engines increase with increasing bypass ratio. Therefore detailed investigations are required in order to avoid greater drag coefficients consuming the advantages of the new engines. Today's best experimental tools for these interference investigations are 'Turbine Powered Simulators' (TPS). Unfortunately, these simulators are not able to simulate the whole spectrum of characteristic features of a full scale engine correctly and simultaneously. Usually, these differences are deemed negligible. In this investigation results of a numerical comparison between a modern turbofan under real conditions and one TPS of Deutsche Aerospace Airbus GmbH, Bremen (DA), are presented. The turbolent, axisymmetric three-dimensional engine flow is simulated numerically by using a finite-volume Navier Stokes code. The influence of the Reynolds number on the aerodynamic quantities is demonstrated both for the actual engine and its scaled down version. The comparison of the scaled down actual engine and the simulator shows differences of the jet characteristics and the drag coeffecients. The results present an insight into the possibilities and restrictions of experimental engine simulations.