基于移动粒子半隐式方法的旋流液膜破碎过程模拟

Simulation on swirl liquid sheet spray process based on moving particle Semi-implicit method

关键词:  锥形液膜  初始雾化  移动粒子半隐式法  破碎过程

Key words:  Conical liquid film  Primary atomization  MPS method  Breakup process

摘要:

为实现旋流初始雾化中液膜破碎过程的直接数值模拟，基于GPU（Graphics Processing Unit）加速和移动粒子半隐式方法（Moving Particle Semi-implicit method, MPS），开发了离心式喷嘴液膜破碎过程的并行加速数值模拟方法与程序，模拟了喷雾场三维形态特征和初始雾化破碎过程。模拟结果成功捕捉到了液膜形成、液膜破碎成液丝继而破碎成液滴的瞬态过程。模拟得到的雾化破碎过程与实验拍摄结果基本吻合。模拟了不同射流速度下的旋流液膜破碎过程，模拟得到的液膜初始破碎长度与经验公式计算结果趋势一致，二者吻合较好，最大误差为24.2%，模拟得到的液膜半锥角与实验值较为吻合，误差为10.6%。表明本文开发的模拟方法与程序的准确性，为后续离心式喷嘴的液膜雾化过程及雾化特性研究打下基础。

Abstract:

In order to realize direct numerical simulation of the primary breakup process of swirling liquid film, a parallel program for simulating the atomization process is developed based on the moving particle semi-implicit (MPS) method accelerated by GPU (Graphics Processing Unit). The 3D spray field characteristics and primary breakup process are simulated. The results show that the MPS method successfully capture the formation of liquid films, the breaking of liquid films into liquid filaments and the breaking of liquid filaments into droplets. The computational results are basically in good agreement with the breakup process images of conical liquid sheet photographed in experiment. The breakup process of swirling liquid film at different jet velocities was simulated, the simulated results of primary breakup length of liquid film are in good agreement with the calculated results of empirical formulas, with a maximum error of 24.2%. The simulated half-cone angle of the liquid film is in good agreement with the experimental value, with an error of 10.6%. The above results show the accuracy of the calculation method, which lays a foundation for the subsequent liquid film atomization process and atomization characteristics of pressure-swirl injectors.