Session: 34-08 LES Solvers and applications 2

Paper Number: 122101

122101 - Large-Eddy Simulations of a High-Speed Low-Pressure Turbine Cascade With Purge Flow 

Future turbofan designs are expected to include gearboxes to allow for the decoupling of the fan and the low-pressure turbine. Doing so will increase overall engine efficiency, but change the design point for low-pressure turbines by allowing to increase the rotation speed. To study these new high-speed turbines, an experimental configuration from the European project SPLEEN, supported by the Von Karman Institute (VKI) and SAFRAN Aircraft Engines, is investigated using Large Eddy Simulation (LES). Three simulations based on the experimental SPLEEN cascade are performed: a baseline case without the purge flow cavity, a case with the purge flow cavity, and a case with the purge flow cavity and 0.9% mass flow rate relative to the main flow. Such complex CFD projects are limited almost exclusively to research and academic domains and help to build a deeper understanding of relevant physics in order to construct better models in the future. The CERFACS AVBP solver is used to reproduce an operating with exit Mach number of 0.9 and Reynolds number of 70000. The simulations capture engine-relevant flow features such as main vortex structures, flow separation, transition to turbulence and transonic Mach number physics that are expected in this operating regime. Despite some differences with the experimental inlet flow angle, the simulations predict the pressure distribution around the blade profile as well as the loss topology present in the experiment for the measured no cavity case with reasonable accuracy. Introducing the cavity and adding purge flow increased the losses in the blade passage, as expected. Further analysis show these increases in losses are linked with coherent vortex structures, caused directly by the inclusion of the cavity and by the addition of the purge flow. Further efforts to simulate the rotating bars would continue to increase complexity of the project and evaluate how the cavity affects the losses after these wakes. 

Presenting Author: Florent Duchaine CERFACS

Presenting Author Biography: Florent Duchaine received a Master degree of science in Mechanics and Energetics from Institut National Polytechnique de Lorraine (INPL – France) and Master degree in Engineering in fluid mechanics and Thermal from Ecole Supérieure des Sciences et Technologies de l’Ingérnieur de Nancy (ESSTIN – France) in 2003. He received a PhD Degree from Institut Polytechnique de Toulouse in fluid dynamics (INPT – France) in 2007. After a post-doctoral position at Cerfacs and IMFT (France) he worked as a researcher at Cerfacs in the CFD and Globc Teams. His activities are related to Large-Eddy Simulations of turbulent reacting flows in turbomachinery components including heat transfer and code coupling on massively parallel architectures.

Authors:

David W. Perkins CERFACS
Florent Duchaine CERFACS