船舶封闭舱室火灾烟气温度特性研究

封闭舱室火灾与开放空间火灾有很大的不同。通过在内尺寸为1m×1m×0.75m的舱室内的一系列不同油盘直径庚烷油池火试验,发现了烟气的循环卷吸现象,且发现舱内气体可以分为上部的密烟气层和下部的稀烟气层两层,此时传统的双区域模型对火灾的模拟不再适用。烟气温度的空间分布可以用一个分段函数来表示,密烟气层内部温度基本一致,温度与高度无关;稀烟气层内部温度随高度具有均匀的梯度,为高度的一次函数。同时,研究发现熄火时刻舱内的烟气温度分布符合波尔兹曼分布律,且与油盘直径无关,即与火源功率无关,满足统一的波尔兹曼方程,并就本实验参数条件下的温度数据给出了拟合曲线方程。

A Study on temperature characteristic in enclosed cabin fire

Fires in enclosed compartments are very different from those at in open space.A series of heptanes pool fire experiments under different diameters of oil pans were performed in a cabin of 1m×1m×0.75m.We found a phenomenon called smoke recycled entrainment.The gas in the cabin can be classified into two layers： one is upper thick smoke layer;the other is lower thin smoke layer.For this situation the traditional two-zone model is not suitable.The special distribution of smoke temperature can be defined by separable function.The inner temperature in the thick smoke layer is nearly uniform,independent on the height;the inner temperature in the thin smoke layer has even gradient with the increase of height,having linear correlation with height.Meanwhile,it is found that the smoke temperature profile,when extinguished,fits Boltzmann distribution with no correlation with the diameters of the oil pans（i.e.the power of the fire）.Fitting curve equation was put forward according to the temperature data in this experiment.