Liu He-Xiang, Wang Yi-Bo, Wang Shao-Yu, Yan Ke-Chuan, Yang Yan-Ru, Wang Xiao-Dong
State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China.
Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China.
Langmuir. 2023 Dec 12;39(49):18052-18059. doi: 10.1021/acs.langmuir.3c02801. Epub 2023 Nov 27.
We investigated the microscale electrohydrodynamic (EHD) conduction pumps in a wide range of working regimes, from the saturation regime to the ohmic regime. We showed that the existing macro- and microscale theoretical models could not accurately predict the electric force of microscale EHD conduction pumps, especially for the cases of a strong diffusion effect. We clarified that the failure is caused by a rough estimate of the heterocharge layer thickness. We revised the expression of heterocharge layer thickness by considering the diffusion effect and developed a new theoretical model for the microscale EHD conduction pumps based on the revised expression of heterocharge layer thickness. The results showed that our model can accurately predict the dimensionless electric force of the microscale EHD conduction pumps even for the cases of a strong diffusion effect. Furthermore, we developed a working regime map of microscale EHD conduction pumps and found that the microscale EHD conduction pumps more easily fall into the saturation regime compared with the macroscale EHD conduction pumps due to the enhanced diffusion effect; in other words, the microscale EHD conduction pumps have a wider saturation regime. We showed that the conduction number could not distinguish the working regime of the microscale EHD conduction pumps because it does not take the diffusion effect into account. By employing the revised expression of heterocharge layer thickness, we proposed a new dimensionless number, to distinguish the working regimes of microscale EHD conduction pumps.
我们研究了微尺度电流体动力学（EHD）传导泵在从饱和区到欧姆区的广泛工作范围内的情况。我们表明，现有的宏观和微尺度理论模型无法准确预测微尺度EHD传导泵的电力，特别是对于强扩散效应的情况。我们阐明，这种失败是由于对异电荷层厚度的粗略估计造成的。我们通过考虑扩散效应修正了异电荷层厚度的表达式，并基于修正后的异电荷层厚度表达式开发了一种新的微尺度EHD传导泵理论模型。结果表明，即使对于强扩散效应的情况，我们的模型也能准确预测微尺度EHD传导泵的无量纲电力。此外，我们绘制了微尺度EHD传导泵的工作区域图，发现由于扩散效应增强，与宏观EHD传导泵相比，微尺度EHD传导泵更容易进入饱和区；换句话说，微尺度EHD传导泵具有更宽的饱和区。我们表明，传导数不能区分微尺度EHD传导泵的工作区域，因为它没有考虑扩散效应。通过采用修正后的异电荷层厚度表达式，我们提出了一个新的无量纲数来区分微尺度EHD传导泵的工作区域。
