摘要
为了探究液体燃料泄漏燃烧特性,以混凝土为底板开展点燃与非点燃条件下乙醇流淌火试验,测量并分析了扩散直径、火焰温度、单位面积燃烧速率等关键参数.根据泄漏速率与燃烧速率的相对关系,将乙醇流淌火燃烧过程划分为扩散燃烧阶段与准稳态燃烧阶段,并分别建立了上述两阶段的扩散直径预测理论模型.扩散直径、火焰温度均随乙醇泄漏速率(40～80 mL/min)增加而增大.其中,当泄漏速率为80 mL/min时,火焰温度峰值最高(约为860℃).此外,在本试验中乙醇流淌火单位面积燃烧速率约为乙醇油池火的68％,这主要是因为乙醇流淌燃烧过程中存在热损失并且乙醇流淌火的火焰热辐射吸收程度更低.
Abstract
To study the combustion and spreading behaviors of ethanol spill fires,an experimental platform specifically designed for liquid fuel spill fires was set up.A series of tests on ethanol spill fires were conducted under various leakage rates,both for ignition and non-ignition scenarios.The characteristic parameters,e.g.,diffusion diameter,ethanol thickness,flame temperature,and unit area burning rate were measured and analyzed.The findings indicate that liquid fuel spill fires can be categorized into two stages based on the correlation between leakage rate and combustion rate:the combustion spreading stage and the quasi-steady combustion stage.In the spreading combustion stage,the diameter of the liquid fuel spread under ignition conditions is approximately 87％of that under non-ignition conditions at the same moment.The results demonstrate that both the diffusion diameter and flame temperature exhibit an upward trend as the liquid fuel leakage rate increases within the range of 40-80 mL/min.Notably,when the leakage rate reaches 80 mL/min,the peak flame temperature reaches its maximum,measuring approximately 860 ℃.Furthermore,as the leakage rate increases,the vertical temperature gradient of the flame becomes more pronounced.This leads to a stronger influence of thermal radiation and convection from the flame.Consequently,the velocity of the airflow around the fire source is accelerated,thereby enhancing the air entrainment capacity.A theoretical model has been developed to predict the diffusion diameter in both the spreading combustion stage and quasi-steady combustion stage of spill fires.The experimental results have been well described by physically based models,demonstrating the accuracy of these correlations.Moreover,in this experiment,it was observed that the burning rate of liquid fuel spill fires per unit area is approximately 68％of that in pool fires.There are primarily two reasons for this phenomenon:firstly,there is a certain amount of heat loss during the flow process due to the heat exchange between the liquid fuel and the concrete floor;secondly,in the combustion process of pool fires,the flame consistently exerts a heating radiation effect on the pool,whereas the heating radiation effect on spill fires is comparatively weaker.
维普
万方数据