幂律型流体雾化SPH方法数值分析

Numerical Analysis of Atomization Process of Liquid with Power Law Model Based on SPH Method

关键词:  光滑粒子流体动力学  幂定律模型  雾化  射流  液膜  撞击

Key words:  Smoothed particle hydrodynamics  Power law model  Atomization  Jets  Liquid sheet  Impingement

摘要:

幂律型流体的雾化过程存在复杂的界面运动,用传统网格法很难精确追踪运动界面。为研究幂律型流体的雾化特性,运用SPH方法对典型的双股幂律型流体撞击雾化问题进行三维数值分析。根据文献实验,采用SPH方法模拟获得与实验条件相应的数值结果,对比后表明,二者雾化角相当吻合,数值结果还成功捕捉到液膜向液丝的破碎过程及网状的液丝分布状态,验证了方法的有效性。分析了射流速度和撞击角度对雾化角的影响,得到雾化角随着射流速度和撞击角度的增加而增大；对雾化后的速度场进行数值分析后表明,撞击点附近,惯性力的作用使速度场变化剧烈；在流体远离撞击点的过程中,粘性耗散作用使速度场趋于稳定,但速度大小小于初始撞击速度。

Abstract:

The atomization process of non-Newtonian liquid with Power Law model has complex interface movement, which is difficult to track accurately with traditional grid-based methods. In order to study the atomization and spray characteristics, the typical problem of two liquid jets impingment and atomization was simulated based on three-dimensional SPH method.Numerical result is obtained with SPH method and the atomization angle shows a good agreement with literature experimental results, and numerical results also capture the breakup process of the sheet to ligaments and the state of ligament-net area, which proves that this method is valid. Through the computation of atomization angle with different jets velocity and impinging angle, it shows that atomization angle increases with the enhancement of jets velocity and impinging angle. Through numerical analysis of the velocity field, several conclusions are drawn. In the area close to impinging point, velocity varies intensively because of the inertia force. In the area apart from impinging point, velocity becomes stable because of viscosity dissipation, however, the magnitude of velocity is less than the initial value.