含内热源可燃多孔介质热量传递及影响因素分析

本文模拟了自然对流及恒壁温边界条件下含内热源可燃填充床内最高温度随时间的变化;计算了侧面和端面取不同换热系数时填充床内的温度分布;分析了对流换热系数、堆积状态等对床内最高温度的影响。计算结果表明:各边界取不同换热系数时对最高温度的影响不大;在环境温度低于383．15 K,或壁面温度低于381．15 K的条件下,多孔床不会发生自燃。对流换热系数较大、堆积密度较小时多孔床也不易自燃。

PARAMETRIC ANALYSIS OF HEAT TRANSFER IN THE COMBUSTIBLE POROUS MEDIA WITH INTERNAL HEAT SOURCE

Maximum temperature history in the packed bed of combustible material with internal heat source was studied numerically under the boundary conditions of convection and constant wall temperature. The temperature distributions within the packed bed at different convective heat transfer conditions were calculated. The influence of packed state on the maximum temperature was analyzed. The results show that the convective heat transfer coefficients on the different walls have a little influence on the maximum temperature. When the ambient temperature is lower than 383.15 K under the boundary conditions of convection or constant wall temperature that is below 381.15K, the packed bed can't combust spontaneously. The spontaneous combustion of the packed bed becomes more difficult under the higher convective heat transfer coefficients and smaller bed density.