Abstract: The interaction of droplets with a shock wave widely exists in the fields of aerospace and fire fighting. And droplet breaking is the key process. At present, the initial diameter of droplet breakup is mainly at the millimeter level, and the research work on numerical study of sub-millimeter droplet deformation and breakup is still insufficient. For the purpose of studying the interaction process of sub-millimeter droplets with a shock wave, based on the existing experimental results, this work used VOF (Volume of Fluid) multiphase flow model and k-ε turbulence model to analyze the motion parameters of droplets in time and space. The influence of different Weber number (We) on the deformation and evolution of sub-millimeter droplets was analyzed by two-dimensional numerical simulation, and the explosive breaking mechanism of sub-millimeter droplets was revealed by three-dimensional numerical simulation. The results showed that Weber number can promote droplet deformation, and the greater the Weber number, the shorter the time required for droplet compression deformation. In the process of compression deformation, the dimensionless transverse deformation width of droplets with different crushing modes changed linearly with dimensionless time. Under the condition of constant aerodynamic force, the centroid acceleration of sub-millimeter droplets in the same crushing mode was inversely proportional to the initial diameter of droplets. The lateral spreading rate of droplets decreased with the increase of Weber number at low Weber number, while increased with the increase of Weber number at high Weber number. The breaking mechanism of sub-millimeter droplet explosive breaking mode was shear-induced entrainment mechanism. The numerical simulation results in this work were close to the comparative experimental results, which effectively illustrated the effect of Weber number on sub-millimeter droplet deformation.

Key words: numerical research, sub-millimeter water droplet, shock wave, deformation and fragmentation, weber number.

摘要： 为了研究激波与亚毫米液滴相互作用过程，基于现有的实验结果，利用Fluent平台，采用VOF (Volume of Fluid)多相流模型和k-ε 湍流模型，通过二维数值模拟分析了不同韦伯数(We)对亚毫米液滴变形演化过程的影响规律，通过三维数值模拟揭示了亚毫米液滴爆炸式破碎机理。结果表明，韦伯数对液滴变形有促进作用，韦伯数越大，液滴在压缩变形阶段所需要的时间越短；在气动力不变的条件下，相同液滴直径条件下，马赫数越大，液滴所受的气动力越大，液滴质心位移的无量纲加速度越大，低韦伯数下液滴的横向展开速率随韦伯数增大而减小，而高韦伯数下液滴的横向展开速率随韦伯数增大而增大。数值模拟结果与对比实验结果相近，有效阐明了韦伯数对亚毫米液滴变形的作用。

关键词: 数值研究, 亚毫米液滴, 激波, 变形破碎, 韦伯数