Monochromatic high-speed photography of solid rocket propellant combustion

Abstract

Eight composite solid propellant formulations containing varying diameter and weight percentages of metallic particles were burned in strand form in two different nitrogen purged combustion bombs at a pressure of 500 psi. High-speed cinematography was used with an argon laser as the primary monochromatic light source. Two illumination approaches were tried, backlighting and frontlighting. Careful examination of the backlighting films revealed that the flame envelopes surrounding the particles could be eliminated and that the true particle size could be obtained. However, Schlieren effects obscured much of the information which was available on the film. The frontlighting technique eliminated the Schlieren effects and allowed good particle behavioral data to be obtained, but the reflected monochromatic light was not sufficient to allow true particle diameters to be taken.