Some properties of a composite solid propellant.

Abstract

Temperature profiles during polymerization, for the infinite solid cylinder, the infinite hollow cylinder and the star perforated infinite cylinder of polyurethane ammonium perchlorate solid propellent, have been determined. They show that the temperature across the solid rises considerably above the wall temperature and exceeds the 60°C (140°F) limit, recommended for the polyurethane propellants, by a considerable margin, often as much as 25°F. An end effect test indicated that a hot region of fleeting duration is present near the ends of the solid. Burning rates, measured radially across a piece of solid propellant, showed that a variation of burning rate with radius is present. The burning rates across a thin walled hollow cylinder of propellant did not vary radially. Correlation coefficients between the burning rate and the maximum temperature gradient for the solid cylinder ere of the order of 0.92, indicating that a high degree of correlation is present between burning rate and polymerization temperature, Correlation coefficients of this magnitude also show that one of the real causes of uneven burning in rocket motors is high temperature during polymerization.