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Validation of a Fully Coupled Fluid-Ablation Interaction Solver for Low and High Temperature Ablators

AMS Seminar Series

Speaker: Alex Zibitsker, The University of Kentucky

Presentation

Seminar Slide Deck (PDF-2.6MB)

Abstract

Hypersonic flight triggers a wide range of complex and coupled aerothermodynamic interactions such as thermo-chemical non-equilibrium and surface thermo-chemistry of ablative thermal protection shields. This interaction rapidly affects the protective material thermal response, triggers ablation and a subsequent change of the surface topology. In this talk, the coupling of the CHAMPS near body-Cartesian solver and the KATS material response solver is presented and validated for low and high temperature ablators at hypersonic speeds. The CHAMPS near body-Cartesian solver is a fully automatic CFD code capable of employing adaptive mesh refinement for shock tracking and moving boundary problems while a near body grid is used to resolve boundary layer gradients for accurate and efficient heat flux predictions. KATS is a three-dimensional material response solver capable of modeling pyrolyzing ablators with included surface reaction models and robust mesh motion algorithms. The coupling framework shown in this work is fully parallelized and designed for accurate interpolations between the fluid and material surface interfaces with varying levels of grid resolution. The coupled solver has been validated against experimental data for the sublimation of camphor in a non-reactive Mach 6 flow environment and for graphite ablation of two blunt body geometries exposed to arc-jet flow conditions. The scope of this talk will include a presentation of the CHAMPS-KATS solver coupling scheme, including a validation study of the FAI solver, and highlight the advantages of the fully coupled simulation for ablation problems.

Biography

Photo of Alex Zibitsker
Alex Zibitsker completed his Aerospace Engineering Bachelor’s and Master's degrees in Technion Israel Institute of Technology. His Master's degree research focused on the development of an ultrasonic diagnostic technique for tracking decomposition front and estimation of temperature in ablating silica-phenolic material exposed to an oxy-acetylene torch environment. Currently, Alex is a 3rd year Ph.D. student in the Gas-Surface Interaction Laboratory at the University of Kentucky. His research focuses on the development of a coupled program capable of simulating high-fidelity interaction of hypersonic flow with ablating material, including the thermo-elastic response. During his Masters’ and Ph.D. studies, Alex participated in three internship programs at NASA Ames research center. His work focused on a range of problems such as ablation front tracking of meteorite samples exposed to arc-jet environment, generation of validation database for ablative materials and derivation of effective properties at the interface of porous materials using filtering techniques.