MIXING, IGNITION, AND COMBUSTION ANALYSIS OF AIR-AUGMENTED SOLID ROCKETS WITH BORON PARTICLES

A theoretical analysis of mixing, ignition, and combustion in the secondary combustor for air-augmented solid rockets with solid particles iti the primary stream is presented. The mixing analysis takes into account the effect of the presence of solid particles in the primary' exhaust. The analysis predicts the penetration of the mixing zone into the primary and secondary, arid also the velocity, temperature, and particle loading distribution within the mixing xone from which the ignition lag time can be calculated. Experimental data on single boron particle ignition and combustion have been used to determine the Nussell number for particle-gas heat transfer as well as the magnitude arid functional dependence of the surface-reaction heat release on system parameters, thus permitting the prediction of heat-up and ignition delay times for single boron particles under any given air-augmentation conditions. Hence, the coupling of the single-particle studies to the mixing analysis is indicated. The predicted mixing lengths of the secondary chamber for air-augmented solid rockets appear to be realistic. The authors, however, emphasize the need for particle trajectory orientation in the primary stream in order to optimize the ignition arid combustion processes in the secomlarv chamber. © 1969 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.