多孔颗粒床阴燃着火实验研究与数值分析

对发生在多孔颗粒床的阴燃着火过程进行了实验研究，针对最常见的加热方式热接触，设计了平板加热的实验模型，实验表明，长时间的缓慢升温后突然出现温度的跃升是阴燃着火的基本特征，采用有限区域临界着火理论进行了数值模拟计算，得出了发生阴燃着火的临界现象的规律，主要包括：（1）燃料床尺寸不变时，如果临界热流密度增加，则临界环境温度降低，临界点燃温度增高；（2）环境温度不变时，如果临界热流密度增加，则燃料床的临界尺寸减小，临界点燃温度增高；（3）热流密度不变时，如果环境温度较高，则点燃的临界尺寸较小，同时临界点燃温度较高，以上结论与实验结果一致。

Study of smoldering ignition of packed beds of porous bodies

Experimental study and theoretical analysis of the smoldering ignition characteristics of a porous packed bed on a hot surface are presented. In the experiments the minimum ignition temperature for initiating smoldering is measured under typical thermal and geometric conditions. The results show that slowly continuous rising of the temperature is a basic characteristic in the smoldering ignition process. A mathematical model is used for predicting the critical parameters for smoldering ignition and the interaction between. It is found that: (1)In the conditions of constant size of bed, the critical ambient temperature for ignition decreases with the increasing of critical heat flux density, while the critical ignition temperature is increased at the same time. (2)If the ambient temperature remains constant, the smaller critical size and the higher critical ignition temperature are needed with the higher critical heat flux density. (3)For an invariable heat flux density and higher ambient temperature, the critical size needed for ignition becomes smaller and the critical ignition temperature increases. All these calculated results are in good agreement with the experimental data.