Numerical Study of Detonation Transfer from Embedded Explosives

We describe our development of a robust multi-material reactive flow solver that we will use to numerically investigate the reaction mechanism of different explosive materials. A simplified model problem, which uses an ideal equation of state and an Arrhenius rate law whose parameters where chosen to mock up a condensed phase explosive, was devised to validate our current solver base. Our target application will consist of varying the radius of a PETN stick which is embedded in a cylindrical puck of PBX-9502 and determining how effectively the detonation transfers to a larger puck of PBX-9502 surrounded by air. The Wide Ranging equation of state and two Ignition and Growth models are used to describe the reactive mechanism for each explosive. The reactive flow solver framework uses level sets to track the interface boundaries between the different materials and the Ghost fluid method with a density extension to enforce boundary conditions across these interfaces. We use a semi-discrete approach to solve the governing equations, where the spatial operator is discretized with Lax-Friedrich flux splitting and a fifth order WENO scheme, while a third order TVD Runge-kutta scheme is used to advance in time.