Extension of the Spalart-Allmaras One-Equation Turbulence Model for Effusion Cooling Problems

Abstract

The choice of materials for spacecrafts is limited by their thermal resistance. The thermal loads can be reduced by blowing out gases through a porous surface. The original Spalart-Allmaras and k-ω turbulence model by Wilcox are designed for smooth, non-permeable walls and therefore have to be adjusted to account for the influence of the injected fluid. This study proposes an extension of the Spalart-Allmaras turbulence model for an improved prediction of the velocity profiles in a turbulent boundary layer with effusion cooling. The new approach is implemented in the finite volume based TAU code developed by the German Aerospace Center (DLR). Several simulations with different blowing settings are performed and discussed in comparison to the results of the original model. The enhancement is validated against experimental data from the Thermosciences Division of the Stanford University. Finally, the approach is applied to the SHarp Edge Flight EXperiment (SHEFEX) III vehicle of the DLR.