Comparison for Steady and Unsteady Simulations for High Pressure Turbine

For the new generation of advanced aero-engines, the turbine design is a key issue to most of the critical engine related factors, such as fuel consumption, component life, weight, duration and cost of the development program. For many years, an important effort has been devoted at Snecma Moteurs to the development, the validation and the industrialization of methods for the prediction of aerothermal phenomena in multi-stage turbines. The purpose of this contribution is to report on the recent advances of Snecma Moteurs CFD tools for aerodynamic turbine design and analysis. Three approaches, based on 3D Navier-Stokes calculations, each of them corresponding to a different level of complexity, are presented for the prediction of the aerodynamic behavior of high pressure turbines, showing the degree of accuracy and maturity that the turbine aerothermal methods of Snecma Moteurs, have now reached. Firstly, two types of steady stage simulation are considered. The first one uses the mixing plane method in order to transfer the flow information between adjacent blade rows, while the second one uses the average passage method proposed by Adamczyk [1]. Finally, the contribution of an unsteady stage simulation is investigated. Comparisons between computational results and experimental data for a high pressure turbine, tested in the frame of the European Research Programs IACA and TATEF are presented. An analysis is also performed, showing the advantages and the drawbacks of each approach for a realistic representation of the flow into a high pressure turbine stage.