Simulations of Low Mach Number Flows and Heat Transfer in Rotating Systems
Résumé
Low Mach number flows can be observed in internal air systems of turbomachinery aeroengines, in particular the secondary air flow extracted from the compressor stage for cooling purpose of the turbine disks. A parallelized domain decomposition technique is proposed for the simulation of three-dimensional flows and heat transfer in a T-shape model rotating cavity, relevant to study this flow. The Navier-Stokes equations, coupled with energy and perfect gas equations, are solved in the framework of the Low Mach Number approximation, allowing a reduction of computational costs by filtering the high-speed sound waves while keeping a good accuracy by considering the compressibility effects. A higher-order solver based on a fourth-order compact spatial discretization associated with a parallelized Fourier method is implemented on a staggered grid. A semi-implicit second order scheme is introduced for time integration. The resulting computational code is parallelized using a hybrid MPI/OpenMP approach. Simulations were performed within an idealized HP compressor inter-disk cavity, while considering conductive exchanges between the walls and the fluid.
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