聚氨酯泡沫反向阴燃的数值模拟

NUMERICAL SIMULATION OF REVERSE SMOLDERING PROPAGATION IN HORIZONTALLY PACKED BED OF POLYURETHANE FOAM

本文根据两步反应机理,建立了2维非稳态燃料阴燃的数学模型。该模型考虑了气体在多孔介质内扩散系数的变化。应用该模型模拟了来流速度对阴燃速度及平均最高温度的影响,结果表明:首先阴燃传播速度随着来流速度的增大而增大,当风速为0.2cm/s时,阴燃速度达到最大值0.0093cm/s,而后随着风速的增大阴燃速度逐渐降低直至熄灭;来流速度对阴燃最高温度影响不大。同时还模拟了氧气浓度的影响、燃料阴燃中气体组分和固体成分的变化以及温度分布情况。

Based on a two-step kinetic mechanism, a two-dimensional, unsteady, numerical model is presented for reverse smoldering propagation in horizontally packed beds of polyurethane foam. The model takes heat transfer into account between solid phase and gas phase. The effects of airflow velocity are numerically simulated on smoldering velocity and average maximum temperature of smoldering fuel by using the model. The results show that, firstly, increasing the inlet gas velocity can increase spread rate. And then the smoldering velocity reaches the maximum value （0.0096 cm/s）. As the inlet gas velocity is further increased, the smoldering velocity gradually decreases and quenching occurs. However, the inlet gas velocity has little effect on the average maximum temperature. The effects of Yo2, and the evolution of gas species and solid compositions are numerically studied. The temperature profile is simulated for smoldering polyurethane foam.