Implementation of an Internal Ballistics Model in OpenFOAM.

A new internal ballistic solver is being developed within the OpenFOAM environment, due to limitations and inflexibility of most commercially available CFD solvers. The first phase in the development of the modules within the framework can capture all expected physical gas dynamic effects associated with the rocket motor. OpenFOam is attractive as it contains a vast library of solvers which can be implemented. The flow solver utilizes the weighted essentially non-oscillatory (WENO) reconstruction method to approximate the numerical fluxes at the boundaries of each cell. This reconstruction method is limited to hexahedral meshes. The internal ballistic model is first implemented in the MATLAB environment for the one-dimensional (1D) case to serve as input for the fully three-dimensional case. Thus, for a given time step the flow can be solved by generating the fluid volume and assigning mass fluxes from the grain. The eventual goal is to create a fully coupled grain burn back and flow solver to be able to fully model a rocket motor for the 2D and 3D case in OpenFOAM. The development of the flow solver with WENO will be the focus of this paper.