Gas‐phase chemical reaction rate expressions ,thermodynamic expressions for each species in the chemical system and gas‐phase species transport properties were integrated into the code of large eddy simulation (LES) ,achieving a four‐step reaction mechanism of methane and fire dynamics simulator (FDS ) in the butt successfully . For combustion , the eddy dissipation concept (EDC) for multi‐component fuel was used .A 0 .3 m diameter methane turbulent diffusion flame was simulated and the predicted results were compared with Global one‐step and two‐step chemical reaction based on infinitely fast reaction .Results show that the four‐step mechanism adapts to the framework of FDS in reproducing the process of fire and simulation results were reliable .The predicted time averaged temperature profiles ,turbulent velocity statistics and primary reactant show highly consistency .At the same time ,this four‐step mechanism can calculate yields of CO2 ,H2 O ,CO and H2 to describe the process of gas‐phase species emission and transport in combustion reasonably .CO2 and H2 O are the main products of methane flame ,and CO ,H2 are important reaction intermediates .The comparison of CO2 and H2O concentration using different mechanism was encouraging and predictions shown some differences in high‐temperature reaction zone and good consistency in other areas .%通过代码修改，在大涡模拟（L ES ）中嵌入气相化学反应速率、组分热力学性质和输运特性三大机理文件，严格意义上实现甲烷燃烧的四步简化机理与火灾动力学模拟软件（FDS ）的成功对接。燃烧模型采用针对多组分燃料的涡耗散概念（EDC ）模型，模拟0．3 m直径的甲烷湍流扩散火焰，并分别与基于无限快反应速率的总包单步和两步化学反应预测结果对比。分析预测结果可知：四步机理能够很好的适应FDS框架，其模拟结果具有可靠性，时均温度、速度和主要反应物的预测结果高度一致；机理导入后可以预测CO2、H2 O以及中间产物CO和 H2的浓度，更合理地描述了火灾中气相产物的产生与输运过程。不同反应机制下主产物CO2和 H2 O浓度对比结果理想，在高温反应区内存在一定的差异，在高温反应区外呈现出高度的一致性。
展开▼
