ALE3D Simulation of Incompressible Flow, Heat Transfer, and Chemical Decomposition of Comp B in Slow Cookoff Experiments

摘要

An ALE3D thermal-fluids model was developed for Comp B (63% RDX, 36% TNT, 1% wax) and applied to a Scaled-Thermal-Explosion-eXperiment (STEX) with slow heating. Solubility and viscosity models were developed for a well-mixed RDX- TNT slurry. Chemical kinetics parameters for a one-step Prout-Tompkins model were obtained using One-Dimensional-Time-to-Explosion (ODTX) measurements and a non- linear regression routine. In the application of the thermal-fluids model, the strong convection of mass, momentum, and energy was reduced at high temperatures and associated low slurry viscosities to make the simulations numerically tractable. The ODTX thermal-fluids simulations show that in the fast experiments, flow reduces explosion times and self-heated liquid rises to the top of the cavity and ignites. The STEX model shows that flow leads to a small delay in the explosion time and ignition near the top of the vessel. Model comparison with STEX thermocouple measurements, suggests RDX settles in the slurry to form a solid-like material in the lower portion of the vessel and a more fluid material above.