Numerical Modeling of Transpiration-Cooled Turbulent Channel Flow with Comparisons to Experimental Data

Transpiration cooling is a promising active cooling technique that provides coolant through a porous wall at a rate sufficient to maintain temperatures below a desired limit. The present study uses ANSYS (R) CFX to numerically investigate the influence of cooling gas injection on the temperature, velocity, and wall skin friction in the boundary layer of a subsonic turbulent hot-gas channel flow for various blowing ratios (F = [0.0025, 0.0035, 0.005]), hot-gas temperatures (T-t = [360, 420] K), and Mach numbers (M = [0.2, 0.3], nu(infinity) = [77.98, 126.25] m.s(-1)). Here, a cooled permeable porous ceramic matrix composite sample with a hot-gas channel flow is simulated using a monolithic and two-domain approach. For the two-domain approach, separate solvers are used for the hot-gas and porous domains, respectively. These are applied alternatively and coupled to each other by boundary conditions imposed at the respective interface. The simulations are validated against experimental data and provide complementary insight into the effects of the cooling, which cannot be assessed from experimental measurements alone. The results show that, although a monolithic approach would be more convenient from a numerical point of view, a two-domain approach has proven to be superior in matching experimental data for this study. Furthermore, improved thermal boundary-layer profiles downstream of the porous sample are obtained by including the aft wall in the coupling process. This study adds to the limited theoretical and numerical investigations found in the literature on transpiration cooling.