Electric measurements of charged sprays emitted by cone-jets
Electric measurements of charged sprays emitted by cone-jets
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DOI：
10.1017/s002211200200798x
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发表时间：
2002-05-25
影响因子：
3.7
通讯作者：
Hruby, V
中科院分区：
文献类型：
--
作者：
Gamero-Castaño, M;Hruby, V
我们使用飞行时间和能量分析技术，在真空中测量的电荷，比电荷和停止电位的初级和卫星液滴产生的磷酸三丁酯溶液的电喷雾。该信息，感兴趣的本身，随后进行分析，以获得以下相关参数的射流从泰勒锥发出的：在破碎点的流体的速度，液体锥和射流破碎位置之间的电压差。也是静脉曲张破裂的最可能波长电喷雾针电压的大部分用于加速射流。事实上，对于这里研究的最低电导率的解决方案，电喷雾针和射流破碎位置之间的电压差变为针电压的约90%。此外，射流流体在破碎点处的压力与其比动能相比可以忽略不计。在静脉曲张破裂中产生的主要液滴的比电荷分布函数是非常窄的。因此，在恒定电位下静脉曲张破裂的限制性和普遍接受的情况与该实验观察不一致。另一方面，电荷被束缚在射流表面的情况似乎是一个很好的近似来模拟电荷对毛细管破裂的影响。还发现，粘度对液滴形成的影响是至关重要的，在电喷雾的中等和高导电性。我们希望这些测量将指导锥形射流的分析建模。
We use time-of-flight and energy analysis techniques to measure in a vacuum the charge, specific charge and stopping potential of primary and satellite droplets generated by electrosprays of tributyl phosphate solutions. This information, of interest in itself, is subsequently analysed to obtain the following relevant parameters of the jet emanating from the Taylor cone: the velocity of the fluid at the breakup point, the voltage difference between the liquid cone and jet breakup location. and the most probable wavelength for varicose breakup. A large fraction of the electrospray needle voltage is used to accelerate the jet. Indeed, for the solutions of lowest electrical conductivities studied here, the voltage difference between electrospray needle and jet breakup location becomes approximately 90% of the needle voltage. In addition, the pressure of the jet fluid at the breakup point is negligible compared to its specific kinetic energy. The specific charge distribution function of the main droplets produced in the varicose breakup is remarkably narrow. Hence, the limiting and commonly accepted case of varicose breakup at constant electric potential is not consistent with this experimental observation. On the other hand, a scenario in which the electric charge is bound to the jet surface seems to be a good approximation to simulate the effect of charge on capillary breakup. It is also found that the effect of viscosity on the formation of droplets is paramount in electrosprays of moderate and high electrical conductivity. We expect that these measurements will guide the analytical modelling of cone-jets.