高原低压环境小尺寸乙醇池火辐射特性的变化

Radiation Characteristics of Ethanol Pool Fire in High-Altitude Area

运用火灾相似模型分析中的辐射相似模型理论,推导了低气压环境下池火辐射特性与常压环境的关系.理论分析表明,池火的辐射分数随气压降低变化不明显,火源对外的热辐射与燃烧速率近似成正比关系.利用合肥及拉萨环境气压差异,在两地开展了边长范围6～24,cm的方形乙醇池火的燃烧速率及辐射通量对比实验,对理论分析进行了验证.实验结果表明,燃烧状态受池火尺寸影响,随燃料盆尺寸的增加,燃烧状态从层流主导向湍流主导过渡,两地燃烧速率比向气压比趋近,两地池火的辐射差异也相应改变.总的来说,拉萨高原环境下池火燃烧速率要普遍低于合肥地区,辐射强度也相对较小.

The radiation characteristics of liquid pool fire were studied by scaling model. Theoretical analysis shows that radiation factor of pool fire doesn＇t change significantly with the decrease of atmospheric pressure, and that radiation is proportional to fuel burning rate. Comparison experiments of ethanol pool fires were conducted in ISO fire test room in Hefei and Lhasa, respectively, and radiation heat flux and burning rate of 12 different size pool fires （side length 6-24 cm） were measured. The experimental results proved the correctness of theory. It was also shown that the burning condition was affected by pool size. With the increase of pool size, the difference of fire radiation in the two places changes. One important result is that, as the burning rate of pool fire in Lhasa is lower than that in Hefei, the hazard of radiation in low pressure area is relatively small, which can provide some advice for fire protection in high altitude area.