持续溢油流淌火燃烧流动耦合特征与蔓延动力学模型研究

Spill fire accidents have some characteristics such as the rapid development ，the larger burning area and the dynamic burning size. The coupling effect of the burning and spread determines the fire spread behaviors. On the one hand, the spread fuel quantity will be decreased due to the participation of burning and the spread characteristic will also be changed because of the increase of liquid temperature. On the other hand, the spread process obviously enlarges the burning area and decreases the thickness of liquid layer which further affects the heat transfer process. As a result, the spreading and burning behaviors of the continuous spill fire are different from those of pool fires. Therefore two scientific topics can be introduced: 1) the spill fire flame characteristics under the dynamic burning areas; 2) the heat transfer process between the spread liquid layer and the substrate. Some continuous spill fire experiments will be conducted to study the spreading and burning behaviors. The flame characteristics of the continuous spill fires are measured and analyzed. Then a modified heat feedback model of the flame can be obtained based on the spill fire flame characteristics. In addition, the radiative penetration through the liquid layer and the convection heat are analyzed in detail. By analysis of the main effect parameters, the heat transfer rate between the liquid layer and the substrate can be determined. Combing the heat feedback from the flame and the corresponding heat transfer process between the liquid layer and the substrate, the burning rate of continuous spill fire can be calculated. In the end, the fire spread dynamic model is developed based on the burning and spreading process. Then the spreading area under the different discharge rates can be calculated. The results enrich the theory of liquid fires and are meaningful to further conduct the risk assessment of the continuous spill fire and the relative firefighting.

持续溢油流淌火灾具有发展迅速、影响范围大、蔓延面积动态变化等特征，涉及流动和燃烧两部分，且二者相互耦合。燃烧实时消耗溢出的油品，同时对油品加热，影响其流动特性，而流动会明显增加燃烧蔓延范围，导致油层变薄，进一步改变油层与底面的传热机理。这种燃烧流动耦合使得其燃烧蔓延规律显著区别于传统的油池火。由此引出两个关键科学问题：1）横纵向同时扩展过程中流淌火焰行为特征；2）燃烧流淌薄油层与底面耦合传热机制。项目拟结合持续溢油流淌火实验，研究流淌火焰行为特征时变规律，确定影响火焰行为的关键因素，进而修正流淌火焰热流反馈模型；研究油层与底面对流换热和辐射透射耦合效应，量化其热流传递速率；然后结合火焰热流反馈及油层热流损失规律，计算流淌火燃烧速率；最后在分析液体流淌规律基础上，考虑油品温升和燃烧速率的影响，构建持续溢油流淌火蔓延动力学模型。研究成果可完善液体火灾相关理论，为其风险评估及应急救援提供参考。

随着我国工业和经济的快速发展，我国对液体燃料的需求量逐渐增加。液体燃料在储存、运输和加工过程中，易发生泄漏扩散，引燃后形成溢油流淌火灾。相比于传统的油池火，持续溢油流淌火灾具有发展迅速、影响范围大、蔓延面积动态变化等特征，是油品流动和燃烧过程的相互耦合。这种燃烧流动耦合使得流淌火的火焰行为特征以及薄油层与底面间传热机制更加复杂。针对以上两点问题，本项目开展了混凝土表面上和水面上的持续溢油流淌火扩散和燃烧实验，研究了流淌火焰行为特征时变规律，确定了影响火焰行为的关键因素，进而修正流淌火焰热流反馈模型；研究了油层与底面对流换热和辐射透射耦合效应，量化了其热流传递速率；然后结合火焰热流反馈及油层热流损失规律，计算除了流淌火燃烧速率；最后结合油品扩散模型和燃烧模型，构建了持续溢油流淌火扩散燃烧模型。研究成果可完善液体火灾相关理论，为流淌火灾的风险评估及应急救援提供参考。