Combustion wave structures of ammonium perchlorate composite propellants

The combustion wave structures of ammonium perchlorate composite propellants have been studied experimentally by means of thermal analysis and microthermocouple techniques. Two types of binders are used in order to examine the impact of binders on the burning rate characteristics. The binders used are hydroxy terminated polybutadiene (HTPB) and hydroxy terminated polyester (HTPE). The oxygen concentration of the HTPE is much higher than that of the HTPB. The results of thermal analysis show that HTPB decomposes exothermically and HTPE decomposes endothermically. The reaction time in the gas phase just above the burning surface is calculated based on the data obtained by the temperature distribution measurements in the combustion waves. The reaction rate of HTPE propellant is found to be higher than that of the HTPB propellant. Though the heat feedback from the gas phase to the burning surface of the HTPB propellant is smaller than that of HTPE propellant, the burning rate of HTPB propellant appears to be higher than that of HTPE propellant. The results obtained show that the chemical properties of binders play an important role not only in the reaction rate in the gas phase but also in the heat release at the burning surface.