Burning surfaces evolution in solid propellants: a numerical model

A methodology for the solution of the internal physics of solid propellant rocket motors is described. The problem involves the simulation of a burning surface - a dynamically changing interface between the solid propellant and combustion gas phases. Burning surfaces can have complex shapes that change in time according to the solid chemistry and deformation, and according to gas parameters. The key element of the proposed model is the development of a new technique to conform the computational mesh to the interface. The paper documents mesh handling and solution procedures suitable for axisymmetric applications. The approach is to treat the problem in a uniform manner for solid and gas phases as a flow with moving sources. Unstructured, dynamically adjusting meshes are employed in the same way for both phases. This paper presents two specific test cases, with non-deforming solids, for which a comparison with theoretical results is possible.