大尺寸固体火箭发动机快速烤燃特性的数值模拟

Numerical Simulation of Fast Cook-off Characteristics for a Large Scale Solid Rocket Motor

为研究装填高氯酸铵/端羟基聚丁二烯(AP/HTPB)推进剂的大尺寸火箭发动机的热安全性问题,针对某固体火箭发动机建立了二维轴对称烤燃简化模型,其中AP/HTPB推进剂的快速烤燃过程采用两步总包反应描述;在升温速率为1. 45、1. 75、1. 95、2. 25及2. 45K/s的工况下,对发动机的快速烤燃行为进行了数值模拟,并与实验数据进行了对比。结果表明,升温速率对着火位置的影响很小,5种升温速率下,AP/HTPB推进剂的最初着火位置均发生在药柱肩部的环形区域内;升温速率k对着火延迟期ti有较大影响,升温速率为1. 45～2. 45 K/s时,二者之间存在线性关系,通过最小二乘法拟合出的经验关系式为:ti=823. 964 81-115. 474 52k。数值计算得到的着火温度和着火延迟期与试验数据的误差分别为0. 6%和1. 72%。

To research the thermal safety problems of large scale solid rocket motor loaded with ammonium perchlorate/hydroxyl-terminated polybutadiene(AP/HTPB)propellant,a simplified two-dimensional axisymmetric fast cook-off model was established for a solid rocket motor,in which the process of fast cook-off for AP/HTPB propellant was described by a two-step global reaction.The fast cook-off behavior of the motor was numerically simulated under the heating rates of1.45,1.75,1.95,2.25and2.45K/s,and a comparison was carried out with experimental data.The results show that the heating rate has little effect on the ignition position.The initial ignition position of AP/HTPB propellant at the five heating rates all occurs in annular region on the outer wall of propellant grain.The heating rate has signficant influence on the ignition delay time t i.When the heating rate is1.45-2.45K/s,there is a linear relationship between the ignition delay t i and the heating rate k,and the empirical relationship fitted by the least square method is determined as t i=823.96481-115.47452k.The deviation of the calculated ignition temperature and ignition delay time with the experimental ones are0.6%and1.72%,respectively.