FLUENT软件预测大尺寸喷射火特性的实用性

A validation study of the fire dynamics simulator Fluent for modeling large-scale impinging gas jet fires

因管道破裂、储罐破损、法兰盘或安全阀失效等发生可燃物质连续泄露并被点燃形成喷射火,不仅发生率高而且具有较大的破坏性.为此,通过分析整理美国标准局发布的大尺寸喷射火实验报告,得到了大尺寸喷射火的有效实验数据,包括喷射火内部的温度分布数据和火焰周围的热辐射分布数据,采用经验公式推导得出火焰几何尺寸;再根据实验报告中各实验工况,利用FLUENT软件对大尺寸喷射火进行全尺寸数值模拟.与实验数据相比,火焰内部温度分布和火焰周围热辐射分布的数值模拟结果的相对误差分别在9.1％～11.2％和7.4％～15.5％,火焰几何尺寸的数值模拟结果与经验公式预测结果也能较好地吻合,从而验证了FLUENT软件模拟大尺寸喷射火特性的实用性,也为喷射火产生的事故后果评价提供了理论依据.

Jet fires, highly destructive and dangerous, will be easily caused by combustible materials leaking continuously from cracks in pipes, breakages in storage tanks, failures of flange plates or safety valves, etc. Therefore, based on the NBS GCR-85-484.. Final Report for Blowout Fire Simulation Tests issued by the US National Bureau of Standards, we studied and analyzed the relevant lit eratures to collect available experimental data, including temperature distribution inside a jet fire and radiation distribution around a jet fire. On this basis, we adopted empirical formulae to deduce the fire geometry. Then, according to the experiments of various conditions in the above report, numerical modeling was conducted by using the commercial CFD package Fluent. Compared with the experimental data on temperature distribution inside a jet fire and radiation distribution around a jet fire, average relative errors on numerical simulation results are in the range of 9.1-11.2% and 7.4 - 15.5% respectively. The fire geometrical parameters deduced from empirical formulae are in good agreement with those from numerical modeling. Consequently, the modeling of large scale impinging gas jet fires by Fluent is validated, which also gives a reference for the consequence assessment of an accident induced by a jet fire.