The effect of counter electrode curvature on the onset voltage and spray angle of the electrospray in the cone-jet mode is experimentally investigated. Six counter electrodes, including a conventional flat electrode, and five curved (both concave and convex) electrodes are considered. The curvature of the curved electrodes was in the range of 10−33.3 m^-1. The applied voltage, the voltage range of the cone-jet mode, and geometrical features such as the liquid cone length and spray angle are measured. It was observed that the ground electrode curvature could manipulate the electric field and equipotential lines in a way that results in higher or lower onset voltage of the cone-jet mode for convex and concave electrodes, respectively. In addition, the operating range or "stability island" grows by convex electrodes and decreases by concave electrodes. Simulation of electric potential lines is introduced to explain this effect further. In general, the ground electrode shape can intensify or abate the density of the equipotential lines in the vicinity of the liquid meniscus at the capillary tip. The cone-jet mode onset voltage equation is modified to include this effect. Moreover, the spray shape was affected by the curved electrodes. In both configurations, the spray angle increases; however, in the case of the concave electrodes, the actual spray coverage is much closer to the theoretical spray coverage.

中文翻译：

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半圆柱形反电极对电喷雾锥-射流模式的影响

实验研究了反电极曲率对锥形喷射模式下电喷雾的起始电压和喷雾角度的影响。考虑了六个反电极，包括常规的平面电极，和五个弯曲的（凹形和凸形）电极。弯曲电极的曲率在10-33.3 m ^-1的范围内。测量所施加的电压，圆锥喷射模式的电压范围以及几何特征，例如液体圆锥长度和喷射角度。观察到，接地电极曲率可以某种方式操纵电场和等电位线，从而分别导致凸电极和凹电极的锥喷射模式的起始电压更高或更低。另外，工作范围或“稳定性岛”通过凸电极增大，而通过凹电极减小。引入电势线模拟以进一步解释这种影响。通常，接地电极的形状可以增强或减弱毛细管尖端处的液体弯月面附近的等势线的密度。修改了锥喷模式的起始电压方程，以包括该效应。此外，喷雾形状受弯曲电极的影响。在两种配置中，喷雾角度均增加；然而，在凹形电极的情况下，实际的喷雾覆盖率与理论喷雾覆盖率非常接近。