Ultrafine particle behavior in electro-hydrodynamic (EHD) flow induced by corona discharge is studied experimentally and numerically. The EHD flow serves as a primary particle aspiration/sampling mechanism, the collector does not require any additional flow generation. Multiphysics numerical model couples the ion transport equation and the Navier-Stokes equations (NSE) to solve for the spatiotemporal distribution of electric field, charge density, and flow field, the results are compared with experimental velocity profiles at the exit. The computed velocity and flow rate data are in good agreement with the experimental data; the maximum velocity is located at the axis and ranges from 1 m/s to 4 m/s as a function of corona voltage. Experimentally evaluated particle transmission trends for ambient and NaCl nanoparticles particles in the 20 nm - 150 nm range are in good agreement with the theoretical models. However, for particles in the 10 nm - 20 nm size range, the transmission is lower due to the increased particle charging resulted from their exposure to the high-intensity electric field and high charge density in the EHD driven flow. These conditions yield a high probability of particles below 20 nm to acquire and hold a unit charge. The transmission is lower for smaller particle (10 nm) due to their high charge to mass ratio, and it increases as the single-charged particles grow in mass up to 20 nm, resulting in their lower electrical mobility. For particles larger than 20 nm, the electrical mobility increases again as they can acquire multiple charges. The results shed insight into interaction of nanoparticle and ions in high electrical field environment, that occur in primary EHD driven flows and in the secondary flows generated by corona discharge.

中文翻译：

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超细颗粒在电晕放电诱导的电流体流动中的行为

通过实验和数值研究了由电晕放电引起的电流体动力学 (EHD) 流中的超细颗粒行为。EHD 流用作初级粒子抽吸/采样机制，收集器不需要任何额外的流生成。多物理场数值模型结合离子传输方程和纳维-斯托克斯方程 (NSE) 求解电场、电荷密度和流场的时空分布，并将结果与​​出口处的实验速度剖面进行比较。计算出的速度和流量数据与实验数据吻合良好；最大速度位于轴处，范围为 1 m/s 至 4 m/s，作为电晕电压的函数。实验评估的环境和 NaCl 纳米粒子在 20 nm - 150 nm 范围内的粒子传输趋势与理论模型非常一致。然而，对于 10 nm - 20 nm 尺寸范围内的粒子，由于暴露于 EHD 驱动流中的高强度电场和高电荷密度导致粒子充电增加，因此透射率较低。在这些条件下，低于 20 nm 的粒子很有可能获得并保持单位电荷。较小粒子 (10 nm) 的传输率较低，因为它们的荷质比较高，并且随着单电荷粒子的质量增长至 20 nm，传输率会增加，从而导致其较低的电迁移率。对于大于 20 nm 的粒子，电迁移率再次增加，因为它们可以获得多个电荷。