Numerical simulation study on thermal response characteristics of DNAN explosive under different flame coating thickness in fire environment
To investigate the influence of flame coating thickness on the thermal response characteristics of ammunition in a fire environment,focusing on the primary controlling mechanism of flame radiative heat flux,namely the flame coating thickness.The composite heat transfer effect of the internal air layer in ammunition and the heat release effect of high-temperature explosive decomposition were comprehensively considered.A numerical model and computational method were developed to predict the thermal response characteristics of ammunition under different flame coating thicknesses.The thermal response characteristics of typical ammunition models under different flame coating thicknesses were simulated.The research results indicate that flame radiance and radiative heat flux increase with increasing flame coating thickness.As the flame coating thickness increases,the temperature rise of the ammunition shows a non-linear increase,and the temperature rise rate also increases.The ignition delay time decreases with increasing flame coating thickness.When the flame coating thickness L<1 m,the ignition delay time decreases non-linearly with the increase of flame coating thickness.When the flame coating thickness L 1 m,the ignition delay time gradually tends to a constant value.Therefore,the impact of flame coating thickness should be fully taken into account in the thermal response of ammunition when flame coating thickness L<1 m.
fire environmentflame coating thicknessthermal response of ammunitionnumerical simulationtemperature rise processignition delay time