We conducted CFD simulations to improve the currently available inkjet technology. This study was motivated by the general problems related to lack of precision control over the quality of droplets emanated from the industrial atomizer sprayers and growing needs for higher quality droplets in the coating industry. We focused on an ultrasonic pulsation atomizer (UPA) capable of producing mono-dispersed droplets operating with waterborne (WB) paint as the working liq-uid. The volume of fluids (VOF) multiphase model was applied to investigate the process of droplet generation under the effects of different factors on the quality of the droplets. Droplets were generated using various novel input waveforms induced on the working liquid in the atom-izer incorporating a piezo sensor. Scaling analysis is used to relate the results of the numerical simulations to larger scale inkjet nozzles being used in industries. Our numerical study specifical-ly examined effects of various parameters including inlet liquid and airflow rates, type of the waveform, frequency of pulsation, viscosity of the working liquid on the quality of the droplets, transfer efficiency, and the optimum working conditions. As a result, the UPA design was found to be capable of producing monodisperse droplets operating under favorable conditions, even without implementing pulsation. Our new design showed excellent capabilities to be used for even higher viscosity fluids, viscosities in the rage of WB paint used in coating industries and produce droplets of acceptable size. With this new design, if the conditions are met, we should be able to control the droplet size and frequency of their generation.

中文翻译：

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水性涂​​料超声脉动雾化器的计算流体动力学研究

我们进行了CFD仿真，以改善当前可用的喷墨技术。这项研究的动机是与以下问题有关的：与对工业雾化器喷雾器产生的液滴的质量缺乏精确控制以及涂料行业对更高质量的液滴的需求不断增长有关。我们专注于超声波脉动雾化器（UPA），该雾化器可产生单分散液滴，并以水性（WB）涂料作为工作液体。应用流体体积（VOF）多相模型研究了在不同因素对液滴质量的影响下液滴的产生过程。在包含压电传感器的雾化器中，使用在工作液体上感应的各种新颖的输入波形来生成液滴。缩放分析用于将数值模拟的结果与工业中使用的更大比例的喷墨喷嘴相关联。我们的数值研究专门检查了各种参数的影响，包括入口液体和气流速率，波形类型，脉动频率，工作液体粘度对液滴质量，转移效率和最佳工作条件的影响。结果，发现UPA设计即使在不施加脉动的情况下也能够产生在有利条件下运行的单分散液滴。我们的新设计显示出优异的性能，可用于更高粘度的流体，粘度高的WB涂料（用于涂料行业），并产生可接受大小的液滴。通过这种新设计，如果满足条件，