National Center for Combustion Research and Development
Indian Institute Of Technology Madras & Indian Institute of Sciences, Bangalore
Experimental Investigation of Cellular Instability in Ammonium Perchlorate (AP) and Fine AP-Binder Mixtures
This paper examines scanning electron micrographs for the size of cells that appear on the burning surfaces of (1) single crystals and pressed pellets of ammonium perchlorate (AP), and (2) mixtures of fine AP particles with polymeric binder, quenched by rapid depressurization at different pressures. While the cellular structures in self-deflagration of AP are well known yet unexamined quantitatively, those on fine AP/binder mixtures are examined in the context of their mid-pressure extinction leading to plateau burning rate behavior of propellants containing them. The results are an experimental validation of the theoretical predictions of Margolis and Williams (1988)  based on diffusionalâ€“thermal coupling in the intrinsic stability of combustion of premixed solids.