Ignition and combustion characteristics of solid propellant under low pressure

This study provides a comprehensive analysis of the ignition and combustion behaviors of HTPB-based ternary solid propellants, focusing on varying environmental temperatures and low pressure conditions. The study covers a pressure range from 0.02 MPa to 0.1 MPa and temperature environments of 10 °C and -20 °C. As pressure and temperature change, the combustion behavior of the propellant undergoes significant alterations. When the ambient pressure is reduced from 0.1 MPa to 0.02 MPa, a marked increase in ignition delay time is observed, with a rise of up to 19.2%. In addition, the ignition temperature climbs by 34.8%. Meanwhile, the burning rate experiences a dramatic decrease, dropping by 35.8%, while the size of the combustion products grows by 38.2%. The propellant's combustion efficiency also declines, with a maximum reduction of 4.8%. Conversely, as the ambient temperature drops from 10 °C to -20 °C, the ignition delay time increases by 14.4%, and the ignition temperature increases by 8.6%. The burning rate decreases by 10.4%, while the combustion product size expands by 7.6%. The combustion efficiency drops by 1.9%. Both reduced ambient pressure and temperature significantly diminish the combustion temperature of the propellant, lower its burning rate, and decrease the combustion efficiency of the solid propellant. To gain a deeper understanding of the propellant's ignition process, we developed a model that effectively captures the influence of both temperature and pressure on ignition dynamics and energy transfer. Compared to experimental data, the average deviation of ignition delay time at different temperatures and pressures is 3.4%, and the average deviation of ignition temperature is 2.3%. This study enhances our understanding of the ignition and combustion processes of propellants under low pressure conditions.