US Army activities in multidimensional modeling of electrothermal-chemical guns

Progress towards developing a first-principles capability to simulate the dominant physical processes in an electrothermal-chemical (ETC) gun is described. The computational model is the CRAFT Navier-Stokes solver, which implements advanced implicit/upwind numerics with strongly coupled chemistry and generalized grid dynamics. The model provides a framework for incorporation of physics submodules. One ETC design examined was a central ullage tube surrounded by a HAN-based propellant. Initial nonreactive simulations in which the ullage tube is initially filled with air at a calculated uniform pressure and temperature and the plasma jet continues to inject into the combustion chamber indicate a potential for a highly structured flow field