高压泄漏喷射火的流动与燃烧耦合作用机制与动力学规律研究

Jet fire induced by high-pressure leakage is an intensive combustion phenomenon that is related to the rupture of pressure vessel or pipeline containing the combustible materials. The high-pressure leakage and jet fire combustion behavior are separately studied without considering the complex interaction between them. Because of the limited knowledge upon the coupling mechanism and dynamics of such interaction, this project will construct an experimental system that can model such jet fire due to high-pressure leakage. By experimental simulation, theoretical analysis and modeling method, the flow structure near the leakage exit (the size and location of Mach disc), state property (pressure and temperature), flow parameter (mass flow rate) and combustion behavior (lift-off distance, flame length and heat flux) will be systematically studied with considering the effect of the leakage tank wall heat transfer conditions, the leakage gas type and the initial state property in tank. The influential mechanisms of the flow structure on the jet fire combustion behavior and the thermal radiation feedback from jet fie on the leakage flow behavior, will be both explored. The model based on the real gas equation of state will be built to predict the high-pressure leakage flow parameter. The radiant fraction model will be established that couples the source Froude number and fuel physicochemical property. The heat transfer equation will also be built to calculate the heat travelling through the leakage tank wall. Finally, these three models, together with the available notional nozzle model, flame size model and line source radiation model, will constitute the dynamical model of the interaction between high-pressure leakage flow and jet fire combustion. This project will provide the scientific basis for preventing and suppressing the jet fire disaster resulting from the high-pressure leakage of combustible gas.

高压泄漏喷射火是储运可燃物的压力容器或管道破裂所诱发的剧烈燃烧现象。目前针对高压泄漏流动过程和喷射火燃烧过程主要进行了孤立式或简单串联式研究，尚未系统揭示两个过程的耦合作用机制与动力学规律。本项目将构建高压泄漏喷射火模拟实验平台，通过实验模拟、理论分析与建模，研究储罐外壁面传热条件、气体种类和储罐初始状态条件对稳态和瞬态泄漏近流场结构（马赫盘大小与位置）、状态参数（压力、温度）、流动参数（流量）和燃烧特性参数（推举高度、火焰长度、热流）的影响规律，揭示泄漏近流场结构对喷射火燃烧特性、喷射火热辐射反馈对高压泄漏流动行为的作用机制，建立并验证基于实际气体状态方程的高压泄漏流动预测模型、耦合喷口Fr数与燃料理化性质的喷射火辐射分数预测模型和泄漏储罐壁传热方程，并耦合现有的虚拟喷口模型、火焰尺寸模型和线源辐射模型，以封闭构建耦合动力学模型。项目将为高压泄漏喷射火灾害预防和扑救提供可靠的科学依据。

高压泄漏喷射火是储运可燃物的压力容器或管道破裂所诱发的剧烈燃烧现象，常次生衍生其他事故，从而扩大事故的规模和后果。但迄今尚未系统揭示高压泄漏流动过程和喷射火燃烧过程的典型边界条件作用规律、耦合作用机制与动力学规律。本项目总结归纳了高压泄漏喷射火灾事故现场的典型环境边界条件，涉及环境旋转风、管道容器破裂口形状、周围障碍物、卷吸进入火焰的细小固体颗粒、爆炸坑道等。.设计建造了高压泄漏喷射火模拟实验平台，借助实验模拟和理论分析，系统揭示了旋转流场、泄漏口形状、障碍物、固体颗粒、爆炸坑道影响高压泄漏喷射火火焰高度、推举高度、温度分布和辐射分数的作用规律和控制机制，建立了多因素耦合影响的喷射火火焰形态和热特性预测模型，可以预测复杂边界条件下喷射火燃烧特性参数。.泄漏过程实质上是一个热力学过程，需借助气体状态方程对泄漏介质的状态参数进行定量描述。在等熵过程假定的基础上，本项目发展了基于van der Waals状态方程的高压气体瞬态泄漏模型，并与基于理想气体状态方程或者Abel-Noble状态方程的泄漏模型对比，发现高压状态下气体分子体积和分子间作用力会加快泄漏过程、减小泄漏时间，并揭示了其影响的内在机制。.本项目从辐射分数的定义出发，通过火焰光学薄假定和参数分析法，在前人倡导的喷口弗劳德数基础上，提出火焰弗劳德数，通过拟合氢气、甲烷和丙烷喷射火辐射分数数据，建立了耦合气体燃料物化特性与火焰弗劳德数的辐射分数模型。模型可以预测其他碳氢气体以及混合气体的喷射火辐射分数。.通过耦合瞬态泄漏模型、虚拟喷口模型、热辐射份数模型、喷射火尺寸模型、线源辐射模型、人体烧伤计算模型、基于无限大固体假定或集总热容法的目标物温度计算模型，构建了高压气体泄漏喷射火热灾害的动态预测与风险评估方法，并利用高达100米的高压泄漏喷射火实验进行了验证，开发了应用系统软件，可实现高压泄漏喷射火的演化模拟。