DEPSCoR: Fragmentation and Melting of Ice Particles Subjected to Hypersonic Aerothermodynamic Environments

A hypersonic flight vehicle will encounter particulates such as dust, water droplets, and ice that can strike the vehicle and damage the surface. These particulates also create disturbances in the flowfield that affects the aerodynamic performance of the vehicles. Recently, research efforts have focused on the interactions between solid par- ticulates and liquid droplets with the underlying flowfield. However, very little known is about the dynamics of ice particulates interacting with a hypersonic flowfield. Unlike rigid solid particulates, ice particles can melt or fracture from the pressure, shear, and heat loads imparted by the flowfield making it difficult to apply current theories and capabilities that have been developed for solid rigid particles to ice particles. The proposed project aims to unravel the underlying processes that occur when ice particles encounter a hypersonic flowfield. Two novel computational tools will be developed in this project to study the coupled dynamics of ice particle-fluid interactions. First, a fluid-structure interaction framework that couples direct simulation Monte Carlo (DSMC) and the lattice particle method (LPM) will be developed to investigate the fracture caused by the impact loads of the bow shock. Second, a heat transfer module to capture the kinetics of liquid layer formation, shear, and growth of the liquid layer for micron-sized particles will be developed. Simulations using these two tools will highlight the key processes that influence the change in shape of the particle as it is transported in the flow. The information gleaned from the simulations will be used to build closure models that can be used in computational fluid dynamics (CFD) solvers. The closure models will be implemented in the state-of-the-art hypersonics CFD code, US3D. Simulations using the US3D code will be performed to understand the influence of ice particles over the entire hypersonic vehicle.