多区域湍流燃烧大涡模拟

Multi-Regional Large Eddy Simulation of Turbulent Combustion

关键词:  有限体积法  湍流燃烧  数值模拟  亚网格尺度模型  多区域求解方法  并行计算

Key words:  Finite volume method  Turbulent combustion  Numerical simulation  Sub-grid scale model  Multi-region approach  Parallel computing

摘要:

为了提高湍流大涡模拟方法在计算复杂工业燃烧设备中反应流体的效率和精度，提出了可以对结构复杂燃烧设备喷嘴内部无反应区域只求解基本流体控制方程，对喷嘴下游燃料反应区域加入燃烧模型进行分区域计算的多区域求解方法，并采用该方法和传统单区域求解方法分别对甲烷-空气预混合湍流燃烧进行大涡模拟。研究结果表明:多区域和单区域求解方法计算所得的轴向和径向时均速度、脉动速度以及OH质量分数一致；不过，多区域求解方法在计算速度上有明显优势，当CPU数量不超过64个时，计算速度可提升14.7% ~ 20.6%；多区域和单区域方法的数值模拟结果与实验值进行了对比，三者吻合较好。

Abstract:

To improve the performance and accuracy of large eddy simulation (LES) for complex industrial applications，a hybrid，multi-regional approach was proposed. For the interior burner flow region without reaction，only the basic flow equations were solved，whereas for the reactive flow region downstream of the nozzle，the combustion modeling was additionally considered. The multi-regional and traditional single-regional approaches were respectively applied to simulate a methane/air premixed flame with LES. The calculated time-mean streamwise and root mean square velocity components and OH mass fraction for multi-regional approach are consistent to the results for single-regional approach. However，compared with the single-regional approach，the LES with the multi-regional method runs much faster，and when CPU number is not more than 64，the improved computational speed can increase by 14.7% ~ 20.6%. Both the numerical results with multi-regional and single-regional approach have been compared with experimental data and they show good agreement.