Study on the model of hot-spot ignition based on friction generated heat on the microcrack face
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摘要: 开展了基于微裂纹界面摩擦生热的细观点火模型研究，采用有限元方法对包含化学反应放热和摩擦生热的热传递方程进行了离散求解，计算模型中考虑了炸药颗粒熔化对升温过程的影响。着重分析了点火模型中主要参数(热点尺度、应变率和界面压力)对炸药点火的影响规律。数值研究表明，随着热点尺度的增大，热点的温度上升越快，越容易发生点火；应变率越大或者界面压力越高，热量积累越快，炸药越容易点火。Abstract: A hot-spot ignition model based on friction generated heat on microcrack face was established. In this model, the heat conduction equation including chemical reaction and friction was solved by implicit finite element method. Furthermore, the latent heat resulting from particle melting was also taken into account in this model. The effects of such key parameters hot-spot size, strain rate, and interface pressure on explosive ignition were detected and analyzed in detail. It is found that the temperature of the hot-spot rises more quickly and the response occurs earlier in time with the increase of the hot-spot size. The accumulation of heat is faster and the explosive is more likely to be ignited where the strain rate is larger or the pressure is higher.
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Key words:
- mechanics of explosion /
- ignition model /
- FEM /
- microcrack /
- friction /
- hot-spot size /
- strain rate
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图 1 微裂纹面热点模型示意图
Figure 1. Configuration of hot-spot model showing friction generated heat
图 3 不同热点尺度情况下热点中心温度随时间的变化
Figure 3. Temperature at center of hot-spot vs. time for the cases of different hot-spot sizes
图 4 不同时刻距离裂纹面不同位置的温度分布
Figure 4. Temperature distribution vs. distance from crack face at various times
图 5 不同应变率下点火时间的比较
Figure 5. Effect of strain rate on ignition time for a constant pressure
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