煤粉射流火焰的大涡模拟及其验证

Large Eddy Simulation of a Pulverized Coal Jet Flame and Its Validation

本文建立了基于欧拉-欧拉体系下耦合了DQMOM模型的大涡模拟方法,对四种工况下的煤粉射流火焰进行数值模拟,并通过实验测量结果验证了数值模型的可靠性.结果表明该大涡模拟方法可以用来分析详细的火焰结构,计算煤粉颗粒的扩散行为和燃烧反应过程,有助于深入理解煤粉射流火焰的着火机理.在数值模拟中,气相温度可以被用来定义着火距离,大涡模拟不仅可以准确预测着火距离随工况变化的规律,还能得到随时间脉动的信息.

Large eddy simulation(LES) coupled with Direct Quadrature Method of Moments(DQMOM) which tracks particles in the Eulerian framework was built and applied to the pulverized coal jet flames under different operating conditions. Experiments in a Hencken-type entrained flow reactor were also conducted to obtain direct photographs and flame ignition distances. The results show that LES can capture the detailed flame structures, track the dispersion and combustion of coal particles and help to understand the flame ignition mechanisms. In the simulations, the gas temperature is a good indication of flame ignition behaviors. LES can well predict the flame ignition distances varied with operating conditions and their fluctuations compared to experiments.