条件矩模型对CH_4-空气扩散燃烧及其NO_x生成的数值模拟

CONDITIONAL MOMENT CLOSURE MODEL FOR SIMULATION OF CH_4-AIR DIFFUSION COMBUSTION AND NO_x FORMATION

采用Bilger提出的条件矩模型 ,在考虑辐射热损失的情况下对CH4-空气湍流射流扩散燃烧及其NOx生成进行了数值模拟 .对于湍流流动和混合分数场采用k -ε - f - g模型 ,对于组分浓度场采用条件矩模型的抛物线型方程 .将模型的模拟数据与美国Sandia国家实验室的实验数据对照结果表明 :条件矩模型能够很好地预报出湍流扩散燃烧的速度场、温度场和主要组分 (CH4、CO2 )浓度场 ,对NO的浓度场的预报结果与实验值的发展趋势相一致 。

Conditional moment closure(CMC) model proposed by Bilger is used for simulation of CH 4-Air diffusion combustion and its NO x formation,taking into account a radiant heat losses in this paper.Simulation is carried out by using k-ε-f-g model for velocity and mixed fractions,and a parabolic equation of conditional moment closure (CMC) for component concentration.A comparison of the prediction and experimental data demonstrates that CMC has good performance in the prediction of the fields of velocity,temperature and main component(CH 4,CO 2) concentration,the prediction of NO concentration is in agreement with in experimental data with acceptable departure.