两种亚网格湍流模型的旋流扩散火焰大涡模拟

为研究旋流火焰结构,采用二阶矩亚网格(SOM-SGS)燃烧模型及Smagorinsky-Lilly和K方程亚网格湍流模型,对美国Sandia国家实验室测量的旋流火焰进行了大涡模拟,得到了与燃烧场速度、温度和温度脉动实测值相吻合的模拟结果。预报的瞬时温度分布云图与实际火焰的形状很相似。K方程亚网格湍流模型预报的瞬时温度分布比Smagorinsky-Lilly模型的预报结果更接近实际。燃烧火焰基本上位于回流区所在的位置,火焰在回流区被稳定。

Large-eddy simulation of swirling diffusion flame using two SGS turbulence models

The structure of a swirling flame was modeled using large-eddy simulations with a second-order moment (SOM) sub-grid-scale (SGS) combustion model, a Smagorinsky-Lilly model and a K-equation SGS turbulence model. The predictions were validated using previous experimental data. The predicted axial and tangential velocities, temperatures and root mean square fluctuation temperatures agree well with the experimental results. The predicted shape of the flame is similar to that observed in the experiments. The predicted instantaneous temperature map using the K-equation model is more accurate than that obtained using the Smagorinsky-Lilly model. The flame is mainly located in the recirculation region where the flame is stabilized.