Numerical model for pellet-dispersion igniter systems

Abstract

A fairly comprehensive practical numerical model for the description of ignition transient flow behavior of pellet-dispersion igniter systems is presented. The model was specifically developed for the study of conventional bag and cartridge igniters employed for small-diameter, composite-propellant rocket motors, but the model in its general form may be adapted for the study of a multitude of ignition transient problems. An extensively modified algorithm based on the random-choice method is applied to obtain the solution of the one-dimensional hydrodynamic equations governing the two-phase core flow behavior within the motor chamber and nozzle, in conjunction with pressure-dependent and crossflow-dependent burning rate equations for the solid propellant and igniter pellets. Good agreement is obtained between experimental firing data and predictions from the model for head-end pressure-time profiles.