| Summary: | This PhD dissertation, conducted as part of a CIFRE research project between TURBOMECA and CERFACS in partnership with the VKI, deals with improving performance of axial turbines from helicopter engines. One of the most critical design points of such engines is the control of the high pressure turbine blade lifetime which face the high temperatures from the combustor. Today, industrial numerical aerothermal predictions of the flows around the blade (in the vein and in its cooling system) are performed with the Reynolds Averaged Navier-Stokes (RANS). Thanks to the increasing computational power, Large Eddy Simulation (LES) becomes affordable to offer further flow predictions. Therefore, this thesis focuses on the capabilities of the LES to estimate the flow in turbine blade internal cooling channels. To simplify this analysis where several physical phenomenon are present, the problem is described in three parts with increasing complexity. The first part addresses simplified typical geometries of cooling channel (U-bend and ribbed channel) in a static configuration. Considering the flow regime, a wall-resolved approach using a hybrid unstructured mesh is proposed in view of the application on an industrial case. The second part extends the study of the ribbed channel in rotation using an inertial reference frame. LES provides mean and unsteady results in good agreement with the available experimental data and previous works, for the flow dynamic and the heat transfer. Finally, the third part presents the application of the method to an industrial case with conjugate heat transfer between a complex cooling channel and the blade. This last section is not present in the public manuscrit for confidential reasons. Results of the use of the wall-resolved approach in rotation in an inertial frame of reference are compared to RANS predictions and show the potential of the method with high local differences.
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