B炸药慢速烤燃过程的流变特性

Rheological properties of Composition B in slow cook-off process

为进一步探究熔铸炸药在烤燃过程中内部各物理场的变化情况,以B炸药为研究对象,完整地建立了基于Bingham流体模型的B炸药黏度计算模型并应用于慢速烤燃的数值模拟。通过数值模拟得到了B炸药在整个升温过程中上中下3个内部测点处的温度变化曲线并以烤燃试验加以验证,观察了弹体内部温度场与对流场的变化特点。结果表明:升温速率为1℃/min时,B炸药相变后逐渐开始流动,内部的温度场分布也随之改变,炸药出现自热反应与最终响应的区域都在弹体上部;升温速率为0.055℃/min时,炸药相变后内部很长时间内仍表现出类固相温度场的分布特点,当炸药出现自热反应后,才逐渐开始流动,温度场也逐渐转变为典型的液相温度场,炸药最终响应点在弹体上部,但最早出现自热反应的区域在弹体中心。

In order to investigate the changes of the internal physical fields of melt-castable explosives in cook-off,Composition B was chosen as the object. A complete viscosity model of Composition B based on the Bingham flow model was first established, and then applied in the numerical simulations of slow cook-off. In this way, the temperature curves of three inner measuring pointsthat located in the upper, middle and lower respectively were obtained and further testified with cook-off experimental measurements. Moreover, the variation of the inner temperature field in the whole process was observed as well.The results showed that when the heating rate was 1 ℃/min, the viscosity flow of Composition B appeared soon after the phase change, and the inner temperature field changed with that. The self-heating and ignition occurred in the upside area of the shell.But when the heating rate was 0.055 ℃/min, the inner temperature field was still like a solid phase after the phase change was completely done for a long time, and the viscosity flow appeared after the self-heating started, the inner temperature field gradually began to change like a liquid phase just at that time. The ignition area was in the upside of the shell too, but the selfheating area was in the middle of the shell. The contradictory points of view in previous studies can be preliminarily explained by this model.