Hybrid RANS/LES Simulation of Combustor/Turbine Interactions

Accurate prediction of thermal field in high pressure turbines is a critical aspect of aerodynamic and durability design. This is particularly true when the flow at turbine inlet exhibits large gradients in temperature, both radially and circumferentially. In other words, in the presence of hot streaks from the combustor. In the numerical study presented in this paper, coupled high-fidelity eddy-resolving simulations of a combustor and a turbine are used to study the differences in the temperature profile at the exit of the first vane and the heat flux on the first blade, resulting from different positioning, or clocking, between the combustor fuel nozzles and turbine vanes. The resolved unsteadiness and turbulence from the combustor impacts mixing and secondary flow in the high pressure turbine. Temperature profiles from both actual combustor CFD simulations, as well as and modulated profiles with more pronounced variation, or pattern factor, are used at the turbine inlet. A threshold of the pattern factor that brings the benefit of clocking is identified. Clocking positioning between the combustor and vanes was studied for the most benefit.