中文摘要：

为加深对湍流燃烧现象的认知,检验动态二阶矩（DSOM）模型在非均匀湍流燃烧中的适应性,本文基于DSOM模型对非均匀入口条件的甲烷空气值班火焰进行了大涡模拟。模拟得到的温度和混合分数分布均和实验数据吻合较好,验证了DSOM模型在非均匀湍流燃烧中的适应性。研究结果表明,在x/D=1和x/D=5的位置温度梯度较大处和混合分数梯度较大处不在同一位置;在火焰的基部存在分层预混燃烧,使得火焰的稳定得到加强;在x/D=15下游,火焰存在局部熄火。

英文摘要：

To promote the understanding of the turbulent combustion,and test the applicability of the Dynamic Second-order Moment Closure（DSOM） model in piloted flame with inhomogeneous inlets,a simulation of a CH_4/air piloted flame that has a steep gradient in mixture fraction at the jet exit is conducted by using the DSOM Model incorporated into the large eddy simulation（LES）.The numerical results of temperature and mixture fraction agree well with experimental data,demonstrating the applicability of the DSOM model for the piloted flame with inhomogeneous inlets.The results also show that the location of high temperature gradient is different from that of high mixture fraction gradient at x/D=1 and x/D=5.Stratified-premixed combustion appears near the base of the piloted flame,strengthening the flame stability.At x/D=15 and further downstream,local extinction occurs.