摘要: |
为了获得有效的预测回火极限的数值模拟方法,对甲烷/空气预混火焰进行了数值模拟。采用不同的反应机理和燃烧模型,针对一个二维轴对称的本生灯,分别对甲烷/空气预混层流火焰和湍流火焰进行了数值模拟,预测了甲烷/空气预混火焰的回火特性,并与Johnson的实验结果进行了对比。对层流火焰的模拟结果表明,采用Smooke-46反应机理能够较为准确地预测层流回火极限。而单步化学反应所预测的层流回火极限要比实验值低得多,这说明单步化学反应下的火焰更难以发生回火。对湍流火焰的模拟结果表明,涡耗散概念模型比有限速率模型更准确地预测了湍流回火极限。有限速率模型所预测的回火极限略高于实验值。 |
关键词: 贫油预混预蒸发 回火 数值模拟 层流有限速率模型 涡耗散概念模型 |
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基金项目:江苏省普通高校研究生科研创新计划资助项目(CXLX12_0167)。 |
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Numerical Simulation of Flashback of Premixed CH4/Air Flame |
WU Ze-jun,HE Xiao-min,GE Jia-wei,HONG Liang,XUE Chong
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(Jiangsu Province Key Laboratory of Aerospace Power Systems,College of Energy and Power Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)
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Abstract: |
To obtain a method of predicting flashback,numerical simulation of premixed CH4/air flame is conducted. Laminar and turbulent flames of a 2D axial-symmetric Bunsen burner were both simulated using different reaction mechanisms and different combustion models. Flashback limits obtained from the simulations are compared with the results of Johnson's experiment. For laminar flame,flashback limits can be well predicted using Smooke-46 reaction mechanism. The flashback limits predicted using single step reaction mechanism are much lower than the values derived from the experiments,it means that flashback is more difficult to occur when single step reaction mechanism is used. For turbulent flame,flashback limits can be better predicted using eddy-dissipation concept (EDC) model than using finite-rate model. Flashback limits predicted using finite-rate model are slightly higher than experimental data. |
Key words: Lean premixed prevaporized Flashback Numerical simulation Laminar finite-rate model Eddy-dissipation concept model |