大涡模拟模型环形燃烧室污染特性

Large eddy simulation of pollution formation in model annular combustor

在任意曲线坐标系下,采用大涡模拟模型环形燃烧室两相燃烧流场中污染物的生成.用亚网格涡破碎(EBU)燃烧模型估算化学反应速率;分别用NO亚网格动力学模型与CO亚网格模型来模拟NO和CO的生成;采用随机离散模型模拟气液两相湍流流动,两相之间耦合采用PSIC算法.计算结果与瞬态速度场、出口温度和污染物质量分数分布的实验数据比较吻合,表明大涡模拟方法和亚网格模型可以用来预估实际燃烧室两相喷雾燃烧流场和污染物生成过程.

In three-dimensional arbitrary curvilinear coordinates, large-eddy simulation （LES） approach was employed to simulate pollution formations in the model annular combustor. The k-equation subgrid scale model was used to simulate the subgrid eddy viscosity, the eddy-break-up（EBU） combustion subgrid scale model was applied to prediction of the chemical reaction rate, the NO subgrid scale pollutant formation model was employed to the evaluation of the rate of NO formation, and a two-step turbulent combustion subgrid scale model was applied for calculating CO concentration. A stochastic separated flow formulation was applied to prediction of instantaneous gas-liquid two-phase turbulent combustion flows. The numerical simulation results were in reasonable agreement with the experimental instantaneous velocity profiles in the primary zone, temperature and pollution concentration profiles at the outlet. It shows that the LES method and subgrid scale pollution formation models in this study can be used to investigate turbulent two-phase combustion and pollution formation processes in combustors.