Fire is the most commonly occurring major accident hazard in the chemical and process industries, with industry accident statistics highlighting the liquid pool fire as the most frequent fire event. Modelling of such phenomena feeds heavily into industry risk assessment and consequence analyses. Traditional simple empirical equations cannot account for the full range of factors influencing pool fire behaviour or increasingly complex plant design. The use of Computational Fluid Dynamics (CFD) modelling enables a greater understanding of pool fire behaviour to be gained numerically and provides the capability to deal with complex scenarios.

This paper presents an evaluation of the Fire Dynamics Simulator (FDS) for predictive modelling of liquid pool fire burning rates. Specifically, the work examines the ability of the model to predict temporal variations in the burning rate of open atmosphere pool fires. Fires ranging from 0.4 to 4 m in diameter, involving ethanol and a range of liquid hydrocarbons as fuels, are considered and comparisons of predicted fuel mass loss rates are compared to experimental measurements.

The results show that the liquid pyrolysis sub-model in FDS gives consistent model performance for fully predictive modelling of liquid pool fire burning rates, particularly during quasi-steady burning. However, the model falls short of predicting the subtleties associated with each phase of the transient burning process, failing to reliably predict fuel mass loss rates during fire growth and extinction. The results suggest a range of model modifications which could lead to improved prediction of the transient fire growth and extinction phases of burning for liquid pool fires, specifically, investigation of: ignition modelling techniques for high boiling temperature liquid fuels; a combustion regime combining both infinite and finite-rate chemistry; a solution method which accounts for two- or three-dimensional heat conduction effects in the liquid-phase; alternative surrogate fuel compositions for multi-component hydrocarbon fuels; and modification of the solution procedure used at the liquid-gas interface during fire extinction.

火灾是化学和加工业中最常见的重大事故隐患，行业事故统计数据突出显示液池火灾是最常见的火灾事件。对此类现象的建模将极大地促进行业风险评估和后果分析。传统的简单经验方程式无法说明影响泳池着火行为或日益复杂的电厂设计的所有因素。计算流体动力学（CFD）建模的使用，可以通过数字方式更好地了解水池着火行为，并提供处理复杂方案的能力。

本文介绍了一种用于对液池火灾燃烧率进行预测建模的火灾动力学模拟器（FDS）的评估。具体来说，这项工作检验了模型预测露天大气池火灾燃烧速率随时间变化的能力。考虑了直径为0.4至4 m的大火，涉及乙醇和多种液态碳氢化合物作为燃料，并将预测的燃料质量损失率的比较与实验测量结果进行了比较。

结果表明，FDS中的液体热解子模型为完全预测的液池火燃烧率提供了一致的模型性能，尤其是在准稳态燃烧过程中。但是，该模型无法预测与瞬态燃烧过程的每个阶段相关的细微差别，无法可靠地预测火灾增长和消亡期间的燃料质量损失率。结果表明，可以对模型进行一系列修改，从而可以改进对液池火的瞬时火势增长和燃烧熄灭阶段的预测，特别是对以下方面的研究：高沸点液体燃料的点火建模技术；结合了无限和有限速率化学的燃烧状态；解决液相中二维或三维热传导效应的解决方法；用于多组分烃类燃料的替代替代燃料组合物；以及在灭火过程中液-气界面处使用的解决方案的修改。