TY - JOUR
TI - Influence of variable heat transfer coefficient of fireworks and crackers on thermal explosion critical ambient temperature and time to ignition
AU - Guo Zerong
AU - Xia Quan
AU - Yan Peiyu
AU - Du Zhiming
JN - Thermal Science
PY - 2016
VL - 20
IS - 5
SP - 1671
EP - 1679
PT - Article
AB - To study the effect of variable heat transfer coefficient of fireworks and  crackers on thermal explosion critical ambient temperature and time to  ignition, considering the heat transfer coefficient as the power function of  temperature, mathematical thermal explosion steady state and unsteady-state  model of finite cylindrical fireworks and crackers with complex shell  structures are established based on two-dimensional steady state thermal  explosion theory. The influence of variable heat transfer coefficient on  thermal explosion critical ambient temperature and time to ignition are  analyzed. When heat transfer coefficient is changing with temperature and in  the condition of natural convection heat transfer, critical ambient  temperature lessen, thermal explosion time to ignition shorten. If ambient  temperature is close to critical ambient temperature, the influence of  variable heat transfer coefficient on time to ignition become large. For  firework with inner barrel in example analysis, the critical ambient  temperature of propellant is 463.88 K and the time to ignition is 4054.9s at  466 K, 0.26 K and 450.8s less than without considering the change of heat  transfer coefficient respectively. The calculation results show that the  influence of variable heat transfer coefficient on thermal explosion time to  ignition is greater in this example. Therefore, the effect of variable heat  transfer coefficient should be considered into thermal safety evaluation of  fireworks to reduce potential safety hazard.