Development of highly accurate tools to predict aerothermal environments and associated effects on vehicles is needed to enable advanced spacecraft for future NASA missions. At heating rates encountered during hypersonic reentry, the surface is ablating and the interaction of ablation products blowing into the boundary layer induces new interactions (chemical reactions, radiation absorption) that have strong impacts on surface heating rates and integrated heat loads. One important effect of the reentry phenomenon is the interaction of the ablated debris with the atmospheric gas molecules and vehicle surface. Even though the ablated debris may include particles ranging from the micron-scale down to the molecular scale, the available models of ablation flows only incorporate ablated molecules and neglect molecular clusters. In this project, we will develop computationally-efficient methodology for coarse-grained yet accurate characterization of cluster reactions with the aid of molecular dynamics (MD) simulations and parametric chemistry models. The resultant product will be a software module which will provide the cluster reaction characterization for the given interaction potential. This module will be compatible with existent NASA codes applicable for continuous or rarefied gas regimes. Another software model will perform MD simulations of energetic gas flow surface interaction.
