变热流对可燃物热解着火特性影响的实验研究

Experimental Study of Variable Heat Flux Effect on Pyrolysis and Ignition of Combustible Materials

固体可燃物热解过程中,热流是一个重要的影响因素。本文设计了线性及平方上升两种热流,实验研究了无点火源条件下榆木及PMMA的热解着火特性,测量了着火时间、表面温度及质量损失的变化规律。结果表明,随着热流上升系数增加,着火时间均减小,榆木着火时刻的表面温度增加,PMMA基本不变,质量损失速率均增大。热流上升系数和着火时间符合较好的幂函数关系。相同热流下,着火时刻PMMA的质量损失远小于榆木的质量损失。

Heat flux has an important effect on the pyrolysis of solid fuels.We designed two kinds of variable heat flux,linearly and quadratically rising heat flux.Experimental studies of ignition time, surface temperature and mass loss were conducted on the non-piloted ignition of elm and PMMA exposed to these two kinds.It indicates that with the increase of the rate of heat flux,ignition time decreases,the surface temperature of elm on the ignition time increases,while PMMA is almost the same,mass loss rate increases.The relation between the ignition time and the rate of increase of heat flux was found to follow a power function.Under the same variable heat flux,mass loss of PMMA is far less than that of elm at ignition time.