Numerical Simulation Research On Thermal Response Of Structure With Explosive Under Fire Circumstance

Structure with explosive like warhead may meet fire arose by tinder, electrical short and arson in the process of manufacturing, transportation, storage and duty. The strength of the structure may debase for the fire’s high temperature flame, and result in poisonous material leaking. Explosive is the key part of the structure, it is heated by the fire. The temperature of the explosive increases gradually and when the temperature reaches some certain value, the explosive is ignited. After the ignition the explosive may appear burning, deflagration even detonation as different boundary and restriction. Predicting and evaluating the thermal response of the structure under fire circumstance is very important for the thermal safety research. Traditional experiment cost a great deal of human resources, material resources and financial, further more the experiment condition is very rigor and is affected by the climate and circumstance. It is different to get unanimous results under those conditions, so numerical simulation becomes a simple and effective method.Firstly, the present research status of the explosive’s response under thermal condition is summarized. The results show that the research before was restricted to single layer explosive’s structure and fixed temperature rise, while there are few literature that focus on the explosive’s response under fire condition. So on the basis of the literature the author put forward his own research contents.Secondly, the thermal response of the explosive before ignition is studied. The numerical models of the main heat transfer problems that affect the inner explosive’s temperature rise are analyzed. Models of poor fire’s heat transfer and temperature rise, C-Bakelite ablatant’s thermal decomposition, inner air layer’s complex heat transfer and explosive’s thermal decomposition are established. How the fire’s temperature rise and emissivity, shell’s emissivity, the thickness of the C-Bakelite affect the inner explosive’s temperature distribution, temperature rise speed and thermal ignition delay time were computed analyzed on the basis of the numerical models by using the FEM software ANSYS. Some law of the inner explosive’s thermal response was got from the results.At last, the quick response of the explosive after thermal ignition is studied. The material models and EOS of the ignitor, high density explosive and the shell are established. Grid detach and node failure at random are used to describe how the crack create and develop. How the shell’s thickness, diameter of the explosive and strength of the ignitor affect the inner explosive’s quick response were computed and analyzed. So this research can make a conference for predicting and evaluating the violence reaction of the explosive after thermal ignition.