Phase Change of Atmospheric Ice Particles in Hypersonic Flows

One characteristic of the post-shock flow field surrounding a hypersonic vehicle is its high enthalpy, generated by compression as shock waves form. When an atmospheric ice particle is exposed to this environment, phase change processes can cause surface recession and partial mass loss. The short time scale thermal response and the irregular shapes of the ice particles require novel simulation approaches. An in-house solver has been developed based on the total enthalpy lattice Boltzmann method to quantify the melting process of ice particles.The thermal solver is verified by comparing numerical results with analytical solutions for three cases. The numerically obtained temperature profile for a sphere is compared with the analytical solution for multiple timestamps. The estimated total time to melt a sphere of ice is also investigated. The last case is the two-phase slab melting with an imposed high temperature at one face, where the different thermophysical properties for the two phases are considered. With the total enthalpy lattice Boltzmann solver verified, a milestone has been reached in the development of a fully coupled framework, in which the direct simulation Monte Carlo solver will compute the flow field in the region around the ice particle, providing the boundary conditions required by the thermal solver. The thermal solver will be integrated with a fully coupled thermal-fluid framework capable of handling dynamic phase change processes, aiming to assist in understanding potential damage to aerodynamic surfaces when hypersonic vehicles encounter a cloud of ice particles.