Numerical simulation of ionized rocket plumes

In this paper, we present a multiphysics numerical approach for predicting the ionization level in solid rocket engine plumes. Ionization takes place in the rocket combustion chamber and charged species flow through the nozzle into an exhaust plume. A low temperature, high-density plasma is created, with small Debye length in most of the plume region. We therefore assume ambipolar diffusion for ions and electrons in the plume and derive a set of conservation equations to be solved by the numerical model. We detail a number of numerical strategies to resolve this system and a novel scheme which enforces charge neutrality. This approach is integrated into a complex code for compressible, multi-species, turbulent flow simulations. Finally, our model is coupled with a Maxwell's equations solver in order to simulate the radar cross section (RCS) of a rocket plume.