Self-pumping transpiration cooling : a joint experimental and numerical study

Abstract

A joint experimental and numerical study is presented to close the current gap in fully coupled data and modeling capabilities for self-pumping transpiration cooling (SPTC). An experimental setup was developed to investigate the effects of the porous medium properties, the flow conditions, and the interactions between solid and coolant on SPTC. Additionally, a two-reference-point, locally emissivity-corrected evaluation methodology for analyzing infrared (IR) measurements was developed, which is valid for quasi-steady evaporation regimes and achieves a better repeatability. For the numerical simulations, we developed an upscaling workflow with pore-network models derived from micro computed tomography (CT) data to accurately describe effective representative elementary volume (REV)-scale parameters and relations. Using upscaled properties, we created a non-isothermal, two-phase Darcy-scale model for the porous medium and modeled free-flow with Reynolds-averaged Navier-Stokes equations, employing an shear stress transport (SST) k-ωturbulence closure to capture near-wall shear stress effects. Coupling conditions ensured mass, momentum, and energy transfer at the interface. The experimental results show a high reproducibility and new insights for the surface temperature at SPTC with the new IR method. The comparison between experimental and numerical results show good agreements. The developed simulation workflow is a major step toward creating a digital twin of an experimental SPTC system. This work lays the foundation for investigating the influence of parameters on SPTC systems and optimizing their efficiency.