星型装药固体火箭发动机烤燃特性

为研究星型装药的固体火箭发动机的热安全性问题，针对装填高氯酸铵/端羟基聚丁二烯（AP/HTPB）推进剂的火箭发动机开展烤燃数值研究。采用两步总包反应描述AP/HTPB的烤燃过程，建立三维烤燃模型对快速、中速和慢速加热速率下火箭发动机的烤燃行为进行数值预测。结果表明：升温速率对着火温度和着火延迟期有一定影响，对着火区域的中心位置、形状和大小有较大影响：在升温速率0.55~1.45 K/s快速烤燃工况下，着火位置紧邻推进剂右侧端面；在升温速率0.005~0.011 K/s中速烤燃工况下，着火区域均呈不连续点状圆环分布，着火点位于翼槽中线上；在升温速率2.4~3.3 K/h慢速烤燃工况下，着火点以翼槽中线呈对称两点分布；随着升温速率升高，着火位置向推进剂右侧端面移动；着火温度T_i与升温速率k呈二次函数关系，即T_i= 516.659 36- 1.267 8k+7.479 4k².

Cook-off Characteristics of Solid Rocket Motor with Star-configuration Propellant Charge

The thermal security of a solid rocket motor with ammonium perchlorate /hydroxyl-terminated polybutadiene (AP/HTPB) is studied. A 3D cook-off model of a rocket motor with star-configuration propellant is established. The reaction kinetic for cook-off is two-step global chemical mechanism. Numerical predictions of cook-off behavior are conducted at fast heating rates, medium heating rates and slow heating rates, respectively. The results show that the heating rate has a certain influence on the ignition temperature and delay period, and has a great impact on the ignition position, shape and size. At fast heating rate of 0.55-1.45 K/s, the ignition is closer to the right end face and the radial section area increases as the heating rate is higher. At medium heating rates of 0.005-0.011 K/s, the ignition zone is distributed with discontinuous point-like rings. The ignition center is located in the midline of wing groove, and the radial section area becomes larger with the increase in heating rate; at slow heating rate of 2.4-3.3 K/h, the ignition positions are symmetrically distributed on the centerline of wing groove. The ignition temperature has a quadratic function relationship with the heating rate, namely, T_i= 516.659 36- 1.267 8k+7.479 4k².