A Scalable Multiphase Flow Solver for Simulation of Hybrid Rocket Motors

One of the challenges to simulating hybrid rocket motors is the fine resolution needed of the liquid interface in order to obtain any droplet pinch-off information. In addition to multiphase flow, it is desirable to include combustion chemistry in these simulations. Both the scalability and versatility of multiphase flow solvers are limitations of open-source software currently available. In this paper, the first challenge of creating a scalable multiphase flow solver is addressed. In exploring the use of a paraffin fuel that creates a melt layer during combustion, a solver is needed to resolve the physics of multiphase flows in the presence of additional processes such as liquid fuel droplets in combustion, gaseous oxidizer in shear interaction with liquid fuel, and a solid fuel grain in regression and deformation. In this study a compressible Volume of Fluid solver is being developed which is scalable and has options for various fluid models. This solver was tested with a Kelvin-Helmholtz instability case to show the capability of the solver to simulate multiphase shear flow. Strong and static scaling analyses show that this solver proves to be a great improvement on current multiphase solvers in terms of scalability, which would allow for more efficient simulation of full hybrid motor layouts.