Abstract Here we implemented a 3D comprehensive Eulerian-Lagrangian model in order to investigate the electrostatic spray transfer processes in the high-speed rotary bell sprayer. This efficient algorithm contains spray dynamics, airflow, paint droplets tracking and an electrostatic effect to simulate atomization. The algorithm is implemented using the OpenFOAM package. A solver for the particle trajectory was used to illustrate the process of spray transport and also the interaction of the airflow and the particle that is solved by momentum coupling. Creating an initial condition of the particle approach has been proposed that is matched with practical applications. The fluid-dynamics is simulated by solving the unsteady 3D compressible Navier-Stokes equations. Unsteady flow is computed by using a Large eddy simulation (LES) turbulence approach, while the motion of the particles is simulated by tracking the droplet size distribution approach. The model correctly predicts that the bell cup spin forces the paint particles to fall off from the bell surface towards the high-velocity airflow. The present work illustrates a tentative benchmark and contains a systematic analysis of the recirculation zone length, the toroidal vortex, the overspray phenomena and the flowfield characteristics like mean velocity, pressure, turbulent kinetic energy and velocity fluctuation. The results indicate as dominant operating parameter the air-paint flow rate with voltage level deeply affecting the spray shape. A more uniform distribution of the coating is obtained by growing this high-velocity shaping airflow, although the values of the transfer efficiency (TE) are reduced. The distribution of the particle size is very sensitive to changes in the rotational speed. Experimental results obtained in this study put forward a clear link between the shaping air flow rate and the rotation frequency on the aerodynamics and also provide valuable insights to design modern ERBS. The paint spray distribution obtained in the present work is validated against coating experimental results with suitable accuracy.

中文翻译：

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汽车喷漆旋转钟杯静电喷漆转印过程数值模拟

摘要 在这里，我们实施了一个 3D 综合欧拉-拉格朗日模型，以研究高速旋转钟形喷雾器中的静电喷雾转移过程。这种高效的算法包含喷雾动力学、气流、油漆液滴跟踪和静电效应来模拟雾化。该算法是使用 OpenFOAM 包实现的。粒子轨迹求解器用于说明喷雾传输过程以及气流与粒子的相互作用，通过动量耦合求解。已提出创建与实际应用相匹配的粒子方法的初始条件。通过求解不稳定的 3D 可压缩 Navier-Stokes 方程来模拟流体动力学。非定常流动是通过使用大涡模拟 (LES) 湍流方法计算的，而通过跟踪液滴尺寸分布方法来模拟颗粒的运动。该模型正确预测钟杯旋转迫使油漆颗粒从钟形表面向高速气流脱落。目前的工作说明了一个暂定基准，并包含对再循环区长度、环形涡流、过喷现象和平均速度、压力、湍流动能和速度波动等流场特性的系统分析。结果表明，作为主要操作参数的空气涂料流速与电压水平深深影响喷雾形状。尽管传输效率 (TE) 的值会降低，但通过增加这种高速成形气流可以获得更均匀的涂层分布。粒径的分布对转速的变化非常敏感。本研究中获得的实验结果提出了成形空气流速与空气动力学旋转频率之间的明确联系，也为设计现代 ERBS 提供了宝贵的见解。在目前的工作中获得的喷漆分布与涂层实验结果以适当的精度进行了验证。