The Internal Flow Modeling of a Simulated Solid Propellant-Liner Debond Using Loci-CHEM

To determine whether a flawed solid propellant would be safe for operational use, one must first verify whether the flaw, which can take form as a crack or fracture (a volume between two propellant surfaces) or a debond (a volume between propellant and liner), will propagate or simply burn out after it ignites. A prediction of whether the flaw will propagate, and to what extent it will propagate, can be made by calculating the pressure distribution inside the burning flaw and then the resultant stress/strain field generated in the solid propellant. However, to precisely predict the pressure distribution and stress/strain field, the flow field, especially at the crack tip, has to be thoroughly understood. The work described herein mainly focused on studying the gas dynamic behavior inside a simulated solid propellant flaw using a computational fluid dynamics approach. In this effort, a finite-volume, density-based Navier-Stokes solver called Loci-CHEM was used. The code replicated experimental results with reasonable accuracy and showed little sensitivity to grid resolution and gas properties assumptions. The pressure distribution was affected by the assumed level of turbulence intensity, which has led to the development of a linearized flow instability model that may be used in the future to better predict turbulence inside burning flaws. Future efforts will use fully coupled fluid dynamics and structural dynamics codes to more accurately predict flaw propagation. To be presented at the AIAA/SME/SAE/ASEE Joint Propulsion Conference (46th), to be held in Nashville, TN, on 25-28 Jul 2010.