Experimental Studies of Flame Propagation in a Small-Scale Hybrid Rocket Motor Configuration

Previous studies of flame propagation on hybrid rocket fuels have been performed on one- to two-dimensional planar studies on slab samples of Poly(methyl methacrylate), acrylonitrile butadiene styrene, and polycarbonate in gaseous oxygen flow settings. This paper further expands upon these studies by presenting a series of experiments tracking flame propagation in the port of a true hybrid motor geometry. A small-scale Poly(methyl methacrylate)/Gaseous oxygen hybrid rocket motor with a transparent combustion chamber is modified with a laser igniter to permit ignition at any longitudinal location along the fuel port surface. Three series of experiments are performed including: a proof of concept validating the experimental design efficacy, and primary and supplementary ignition tests demonstrating flame propagation rates in different local oxidizer flux regimes. High-resolution video capture provides a visual study of the combustion process and computer code assists in performing accurate flame tracking measurements.