Collings模型预测微液滴最大铺展直径因数研究

Prediction of Maximum Spreading Diameter Factor of Micro Droplets Based on Collings Model

目的—微液滴撞击平面基底承印物表面的铺展行为决定喷墨网点的大小,决定数字喷墨印刷成像的质量,研究微液滴撞击平面基底的铺展行为对印刷行业具有重要意义。方法—研究Collings等人的液滴撞击平面铺展模型,基于能量平衡方程推导Collings模型表达式,得出最大铺展直径因数与韦伯数、接触角的函数关系,而且将模型计算结果和试验数据进行对比,分析总结Collings模型公式的适用范围。结论—该模型在液滴直径较小、撞击速度较慢、液滴的韦伯数介于[15,115]、雷诺数远大于韦伯数的条件下,对液滴的最大铺展直径因数具有较好的预测能力;其它条件下,需要考虑更多的物性参数才能更准确地预测微液滴最大铺展直径因数。

The spreading behavior of the droplets against the flat substrate determines the quality of the printing image,so the study of droplet spreading behavior is beneficial to improve the quality of printed products and is of great significance to the printing industry.In this paper,the Collings model to characterize the spreading behavior of droplets impacting on a plane substrate was investigated.It is deduced from the energy balance expression of Collings model,and the relationship among the maximum spreading diameter factor,the Weber number,and the contact angle is obtained and verified.The application scope of the formula is analyzed and summarized via the comparation between calculation results and the experimental data.Under the conditions of small droplet diameters,slow impact speeds,Weber number from 15 to 115,and Reynolds number much larger than Weber number,the model has a good prediction ability for the maximum spreading diameter factor of droplets;under other conditions,more physical parameters of liquids need to be considered to predict the maximum spreading diameter factor of droplets more accurately.