Numerical Investigation on the Transient Ignition Behavior Using CFD-DEM Approach

Abstract

To consider the effects of dynamic collision during the ignition process, numerical simulations based on the CFD-DEM (computational fluid dynamic-discrete element method) approach are carried out for studying the gas-solid transient ignition behavior in guns. The motion of individual particles is modeled by DEM, tracking the dynamic collision process of particles and predicting the dynamic collision phenomena at the individual particle scale. The gas motion is described by the continuum flow, taking into account detailed grain combustion, particle-particle collisions, particle-wall collisions, interphase drag, and heat transfer between the gas and solid phases. A parameter study including particle size, particle escape, initial pressure of primer, initial particle bed height, rupture pressure of holes, and randomness on the ignition phase are investigated. The randomness of vent holes opening closely linked with the particle distribution, particle collision, and combustion process is evidently shown. There is mutual restriction between different factors and the perfect ignition performance cannot be obtained by changing one or two factors. Simulation results show a deeper understanding of ignition processes, including combustion, flame spreading, pressure wave developing, and particle collisions. A further guide for optimization of the igniter design is provided by the parameter study on ignition performance. This article puts forward a new prediction tool for the understanding and design of transient ignition process in guns.

Keywords:

• CFD-DEM
• Ignition behavior
• Interior ballistic
• Two-phase flow