| Propellant performance, physical properties, and burning rate data were determined for a composite solid propellant, containing an ammonium perchlorate oxidizer, a synthetic polymer (PBAN) binder, aluminum as a fuel additive, and solvent refined coal as a fuel. Solvent refined coal is a processed form of coal that has had most of the sulfur and ash removed. A one dimensional equilibrium combustion model is discussed and was used to calculate theoretical performance parameters that were used to evaluate candidate propellant formulations prior to the testing of thin propellant strands in a pressure vessel (Crawford Bomb) to determine the linear burning rate and burning rate stability of the propellants. The candidate propellant formulation chosen for rocket motor testing contained 80% ammonium perchlorate, 14% PBAN, 2% aluminum, and 4% solvent refined coal. This propellant was fired first in small rocket motors and then a larger rocket motor to verify and quantify the propellant burning rate law and the propellant characteristic exhaust velocity, thrust coefficient, and specific impulse. Standard propellant performance data for the SRC propellant is tabulated.; An economic analysis was also performed comparing the relative costs of a rocket motor containing the solvent refined coal propellant with a typical composite PBAN-aluminum propellant, and showed the solvent refined coal propellant, even though it was of lower performance, to be cost competitive. |
