The MIT Center for Exascale Simulation of Coupled High Enthalpy Fluid-Solid Interactions (CHEFSI) is a US Department of Energy Predictive Science Center sponsored by the National Nuclear Security Administration through the Predictive Science Academic Alliance Program (PSAAP). CHEFSI is administered through the MIT Institute for Soldier Nanotechnologies (ISN), a DoD University-Affiliated Research Center (UARC). It is a joint venture between the ISN, the MIT Center for Computational Science and Engineering, and the MIT Schwarzman College of Computing.
CHEFSI’s main objective is to develop a predictive exascale simulation capability for analyzing the complex physical responses resulting from the interaction of high-enthalpy flows and thermal protection systems (TPS). Under the range of extreme conditions that this project will tackle (up to Mach 25, altitudes 50–80 km, surface temperatures ≈1800 K, heating rates ≈1 MW/m2), which are usually found in the high altitude stage of the atmospheric reentry of space vehicles, asteroid entry, and operation of hypersonic vehicles, the airflow is in a state of partial ionization and the solid material can be found in complex non-equilibrium thermodynamic states, leading to chemical and microstructural changes, pyrolysis, ablation, degradation and failure. Conversely, the flow is affected by surface geometry changes due to ablation, by the reentrainment of gaseous products from chemical reactions occurring in the material, and by the heat irradiated from the hot material surface and gas in the shock layer.
The predictive simulation of these environments and their coupled effects on TPS is critical to the success of future space missions, as well as for the design and operation of hypersonic vehicles and reusable and cost-effective spacecraft. This problem poses a formidable simulation challenge with mission-critical implications for both space exploration and national defense.
