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采用计算流体动力学(CFD)数值模拟方法分析了湍流与化学反应相互作用下MILD煤粉燃烧的微观特征。比较了涡耗散模型(EDM模型)和涡耗散概念模型(EDC模型)对MILD煤粉燃烧的影响,两者得到的速度场、温度场、烟气成分等结果与实验结果符合较好.在此基础上分析了MILD煤粉燃烧湍流和化学反应的微观特征尺度,发现采用EDC模型能更准确地反映MILD煤粉燃烧的微观特征,即山于强烈的烟气内部再循环导致的高湍流混合和烟气稀释后低氧浓度下的缓慢化学反应.
The microcosmic characteristics of MILD pulverized coal combustion under the interaction of turbulence and chemical reaction were analyzed by the computational fluid dynamics (CFD) numerical simulation method. The effects of eddy dissipation model (EDM model) and eddy dissipation conceptual model (EDC model) on the combustion of MILD pulverized coal are compared. The results of velocity field, temperature field and flue gas obtained from the two models are in good agreement with the experimental results. On this basis, the microscopic characteristics of turbulent flow and chemical reaction in MILD pulverized coal combustion are analyzed. It is found that the EDC model can more accurately reflect the micro-characteristics of MILD pulverized coal combustion, ie high turbulence caused by intense internal recirculation of flue gas Slow chemical reaction at low oxygen concentration after mixing and dilution with flue gas.