Coupling of Free and Porous Media Flow with Material Recession on NASA Flow Tube Experiment

In the study of Entry, Descent and Landing Technology, a key area of focus, in recent years, has been to develop a thermal protection system capable of sustaining the extreme conditions of atmospheric entry, that include hypersonic flow regimes, thermochemical reacting flow, and ablation. The current research focuses on developing the numerical approach to model the atmospheric entry process, using a computational fluid dynamics solver from the University of Kentucky, KATS-FD. Although the KATS-FD solver can only provide one piece of the puzzle that constitutes the entire simulation of entry descent and landing technology, it provides vital information about the properties of the flow that cannot be attain simply with empirical testing. One of the many difficulties in modeling the entry process is in accounting for the interface between fluid state and solid state. These regimes can be simulated individually, but their coupling is still a major obstacle for researchers in the field today. The topic of the proposed research aims to simulate the NASA Ames Flow Tube experiment, performed by Dr. Francesco Panerai, with the objective of simulating the coupling process of air, initially in free stream conditions, then in porous media regimes, specifically through a mass of Phenolic Impregnated Carbon Ablator, PICA, a recent material of interest in TPS studies. KATS-FD will be used to solve the above case by utilizing a modified Darcy-Brinckman equation that can eliminate the need for current assumptions about the conditions at the boundary layer and integrate the most recent physical models. The successful coupling of the two regimes would be a stepping stone for initial numerical simulation efforts, anticipating the capability of one day modeling the entire atmospheric entry simulation.