雾化过程的一种Euler-Lagrangian耦合算法（英文）

An Euler-Lagrangian coupling method of primary atomization

对雾化过程的直接数值模拟需要巨大的计算资源和时间,而工程中的简化模型则经常会给出错误的结果。因此,可以折中地采用一种混合方法,即在不同尺度上采用不同的模型。提出了一种雾化过程的欧拉——拉格朗日耦合算法。较大的液团采用VOF法直接求解,与网格尺度相当或更小的液滴则采用双向耦合的拉格朗日粒子法进行追踪。而该方法要求粒子的体积小于网格体积的10%,为此又提出了一种虚网格粒子追踪法。由于湍流结构对雾化过程的影响很大,故湍流采用了大涡模拟模型。采用多个算例对开发的算法进行了验证,并对部分关键参数的影响进行了深入研究。采用新算法对两股撞击射流的雾化过程进行了研究,瞬态和统计结果均表明新算法能够给出良好的预测。

For primary atomization simulations, Direct Numerical Simulation （DNS） requires huge computational resources and time, and simplified models used cursorily in engineering usually give unphysical results. Then a method with hybrid models in different scales is a compromise. An Euler-Lagrangian coupling method of primary atomization is proposed in this paper. The larger liquid blobs are captured by the Volume-of-Fluid （VOF） method, and the droplets comparable with the grid volume or smaller ones are tracked by a two-way coupling LPT model. Since the volume of a La- grangian Particle Tacking （LPT） particle must be less than 10% of the Lagrangian cell volume, a new LPT method on a virtual mesh is proposed. And a Large Eddy Simulation （LES） model is used to de- scribe the larger vortex structures which are one of the determinants for primary atomization. The de- veloped code is verified by several cases, and some key parameters are investigated to improve its precision. The primary atomization of two impinging jets is calculated by the new method, and the re- suits of instantaneous and time-averaged characteristics show that the new method can give promising prediction.