Development and Analysis of a Multiphase Model-Informed Closure Relation for Steady Detonation Behavior of Energetic Materials

The steady detonation behavior of energetic materials (EM) in response to shock loading is a key component of performance characterization. The reactive Euler equations serve as the theoretical foundation of many hydrocodes that are used to predict the behavior of EM at engineering scales. An expression referred to as a closure relation is required to ensure a unique solution to the system equations. However, the form of this closure relation, as well as its ability to faithfully represent the underlying physics, continues to be a topic of significant debate within the energetics community. Unlike traditional pressure-dependent reactive burn models such as ignition-and-growth, the use of more recent models for energetics may lead to inaccurate predictions if the selection of closure relation is not appropriate. Here, we discuss the results of a unified mixture/multiphase modeling framework to express the closure relation in terms of simplified inter-constituent interactions. This allows us to pose a new closure relation that better reflects the transport processes between mixture components. We examine the effects of this new closure model on the reaction zone structure for ideal and non-ideal EM, and compare the results to those using conventional closures.