Evaluation of quasi-static pressure by post-detonation combustion

Abstract

A shock wave propagates from the surface of a detonating solid explosive (C4) into an air-filled, cylindrical container. The container is divided into two separate compartments by an interior partition with a circular hole in the center of the partition. The detonation occurs in the left hand compartment, and the explosion vents into the adjacent right hand compartment. The problem is axisymmetric and time dependent, and is numerically solved using the compressible Euler equations with finite rate chemistry. The chemical kinetics model is a single, global, forward reaction where the products of detonation (called fuel) react with the air in the compartment to form combustion products. A nonlinear, virial equation of state is used in the calculations because initial pressures and densities are far above the range where the ideal gas assumption is warranted. All of these equations serve to describe the combustion of the fuel in the compartment that has been heated and pressurized by the strong shock that propagates from the initially spherical explosive toward the compartment walls, and through the vent hole into the adjacent compartment. Solutions were obtained for expansion of the detonation gases through three successively smaller vent holes. Each solution shows a spherical shock wave propagating outward from the detonation toward the walls of the right hand compartment. As the shock wave reflects within the left hand compartment of the cylindrical container, isolated regions of unburned fuel and air see local increases in temperature, pressure, and density caused by superposition of the reflecting shock waves, thus sustaining combustion. Part of the shock wave passes