A STUDY OF COMBUSTION AND FLOW BEHAVIOUR IN SOLID-PROPELLANT ROCKET MOTORS

A comprehensive study of several important aspects of SRM internal ballistics has been undertaken in the present work. Numerical models have been developed for the solution of the quasi-steady and unsteady, one-dimensional, hydrodynamic equations of motion governing the two-phase core flow behaviour within the motor chamber and nozzle. A new phenomenological model of erosive burning has been developed and incorporated into an overall solid-propellant combustion model, which in turn is solved in conjunction with the equations of motion for the SRM. The quasi-steady internal ballistics predictions based on the phenomenological combustion model are consistent with experimental observation. In concurrence with the quasi-steady flow analysis, a new phenomenological model was also developed for the description of normal acceleration effects on the combustion process, for the parametric study of spinning, composite-propellant SRMs.; The internal ballistics of an SRM within various longitudinal acceleration environments was studied analytically with the use of a comprehensive unsteady numerical model. Motors undergoing a relatively constant forward acceleration experience a negligible change in chamber pressure, in agreement with quasi-steady predictions. Small-amplitude, longitudinal oscillation of a motor near the internal chamber's natural frequency produces an amplitude-limited, re-reflecting compression wave and an accompanying rise in base pressure. Additional numerical analysis of the ignition transient flow behaviour of pellet-dispersion igniter systems for small-diameter, composite-propellant SRMs was undertaken. Good agreement is obtained between experimental firing data and the model's prediction for the head-end pressure-time profile.