501 IGPM501.pdf        January 2020
TITLE Effective boundary conditions for transpiration cooling applications
AUTHORS Valentina König, Siegfried Müller
ABSTRACT Transpiration cooling is numerically investigated, where a cooling gas is injected through a carbon composite material into a hot gas channel. To simulate this process efficiently an effective problem is derived, where effects induced by micro-scale structures on macro-scale variables, e.g. cooling efficiency, are taken into account without resolving the micro-scale structures. The key idea of the effective model is to determine effective boundary conditions at the interface between hot gas and porous medium flow. These are derived using an upscaling strategy. Numerical simulations in 2D with effective boundary conditions are compared with results obtained from computations with uniform and non-uniform injection. The computations confirm that the effective model provides a better approximation of the cooling efficiency than the uniform injection.
KEYWORDS effective boundary conditions, upscaling strategy, transpiration cooling, two-domain approach, compressible flow, porous medium flow