该文对甲烷-空气湍流平面射流预混火焰进行了直接数值模拟。射流入口的扰动速度数据依据给定的湍流能谱生成,利用入口处的湍流积分长度尺度和湍动能确定了能谱的峰值波数。计算结果给出了气体温度、质量分数和涡量模的瞬态分布,表明在剪切层内随着旋涡尺度的增大出现了拟序结构。化学反应受到湍流的作用,瞬时反应面出现了明显的皱折,反应面积增大。沿射流中心线,湍动能逐渐衰减,温度脉动和甲烷质量分数脉动均方根值则逐渐增大。

Methane-air turbulent premixed planar jet flames are simulated using direct numerical simulations. A fluctuating velocity field at the jet inflow boundary is generated based on a prescribed turbulent energy spectrum. The peak wavenumber in the energy spectrum is determined from the turbulent integral length scale and turbulent kinetic energy at the jet inlet. The model also gives the instantaneous distributions of the gas temperature, species concentrations, and vorticity. The results show that coherent structures in the shear layer gradually appear as the eddy sizes increase. The chemical reactions are affected by the turbulence and the instantaneous reaction surface is quite wrinkled with its area increase. The turbulent kinetic energy gradually decreases, while the root mean squares of the temperature and methane concentration fluctuations increase along the jet centerline.