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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。
In order to obtain an effective numerical simulation method for predicting the tempering limit, the methane / air premixed flame was numerically simulated. A two-dimensional axisymmetric Bunsen burner was used to simulate the methane / air pre-mixed laminar flame and turbulent flame with different reaction mechanisms and combustion models. The tempering characteristics of methane / air pre-mixed flame were predicted , And compared with Johnson’s experimental results. Simulation results of laminar flame show that the laminar tempering limit can be predicted accurately by Smooke-46 reaction mechanism. The single-step chemical reaction predicted laminar tempering limit is much lower than the experimental value, indicating that the single-step chemical reaction of the flame is more difficult to temper. The simulation results of turbulent flame show that the eddy dissipation conceptual model predicts the turbulence tempering limit more accurately than the finite rate model. The tempering limit predicted by the finite rate model is slightly higher than the experimental value.