基于Gerris的柴油近孔射流雾化数值模拟  

Numerical Simulation of Diesel Near-hole Jet Atomization Based on Gerris

作　　者：何天宇 魏明锐[1,2] HE Tian-yu;WEI Ming-rui(School of Automotive Engineering,Wuhan University of Technology,Wuhan 430070,China;Hubei Collaborative Innovation Center for Automotive Components Technology,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学汽车工程学院,武汉430070 [2]武汉理工大学汽车零部件技术湖北省协同创新中心,武汉430070

出　　处：《武汉理工大学学报》2022年第11期66-72,共7页Journal of Wuhan University of Technology

基　　金：国家自然科学基金(51706163).

摘　　要：为更加深入了解柴油射流破碎机理,基于流体体积法(VOF)结合自适应网格加密技术(AMR),在Gerris中建立了一种柴油射流雾化的数值计算模型,根据Ghiji的试验数据对模型的准确性进行了验证。在此模型基础上探究了喷油压力、扰动频率和扰动幅度对近孔射流雾化的影响。结果表明,相较于采用OpenFOAM的结果,Gerris可以实现射流破碎过程的更精确描绘,更准确地捕捉液滴的分布;提高喷油压力能够加剧液柱表面扰动,促进射流破碎;施加强迫扰动后,射流表面出现周期性波节结构,射流表面波的形成与发展受高频扰动影响较小。随着频率的增加,脱落液滴总体积先减小后增大,脱落液滴数量呈先增大后减小,扰动频率大于6400kHz后两者呈振荡状态。相较于未受扰动状态,1600kHz时脱落液滴数量增加了30.4%;高扰动幅度下的射流液相破碎程度更高,扰动幅度为0.5时脱落液滴数量增加了86.5%。In order to further understand the mechanism of breakup of diesel jet,a numerical computing model of diesel jet atomization was built in Gerris based on volumetric fluid method(VOF)combined with adaptive mesh refinement(AMR),and verified its accuracy based on the test date of Ghiji.Based on this model,the influence of injection pressure,perturbation amplitude and perturbation frequency on the near-nozzle jet atomization are explored.The results show that the Gerris can achieve a more accurate description of the jet breaking process and more accurately capture the droplet distribution,compared with the numerical simulation result of OpenFOAM;increasing the injection pressure can exacerbate the surface perturbation of liquid columns and promote jet breaking;after adding forced perturbation,the periodic nodal structure appears on the surface of liquid columns,and the formation and development of the jet surface wave are less affected by the high-frequency perturbation.With the increase of frequency,the total volume of droplets first decreased and then increased,and the number of droplets first increased and then decreased.When the disturbance frequency was greater than 6400kHz,the total volume of droplets and the number of droplets both are oscillating.Compared with the undisturbed state,the increase of the number of droplets rate about 30.4%;the liquid phase of the jet was more fragmented at high disturbance,and the increase of the number of droplets rate about 86.5%when the perturbation amplitude was 0.5.

关 键 词：柴油 雾化 Gerris 流体体积法(VOF) 强迫扰动 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]