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Electrically driven liquid and liquid film flow in large and small scales in the presence and absence of phase change.

机译:在存在和不存在相变的情况下,电驱动的液膜和液膜以大比例和小比例流动。

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摘要

Electrohydrodynamic (EHD) conduction pumping is associated with the heterocharge layers of finite thickness in the vicinity of the electrodes, generated by the process of dissociation of the neutral electrolytic species and recombination of the generated ions. This theoretical and numerical study provides a fundamental understanding of electrically driven liquid flow based on conduction phenomenon in macro-, micro- and nano-scales. The role of EHD conduction mechanism is also studied for heat transfer enhancement in numerous applications which involve both single phase and stratified two phase models with phase change.;In the fundamental part of this study, a numerical model is developed to study electrically driven liquid and liquid film flow. The results are validated against available experimental measurements of EHD conduction pumping of isothermal liquid film under various operating conditions. The numerical model is further expanded to include the phase change process due to the liquid evaporation or condensation.;A matched asymptotic analysis is conducted to study the interaction of the electric double layer and heterocharge layer in macro-scales. In addition, the effect of electrokinetically induced double layer due to the presence of surface zeta potential and the coupling of such layer with the dissociation-induced heterocharge layer is studied to explore the impact of this coupling on the flow structure and volumetric flow rate in micro- and nano-scales. Finally, a linear stability analysis is conducted for a parallel flow subject to bipolar charge dissociation with additional focus on its heat transfer characteristics. It is observed that charge dissociation at sufficiently high levels promotes instabilities in a Poiseuille flow.;The application segment of this study concentrates on the innovative active heat transfer enhancement techniques using EHD conduction phenomenon in macro- and micro-scales in terrestrial and micro-gravity environments. The applications range from utilizing EHD as the sole pumping and augmentation mechanism to adopting EHD conduction as an auxiliary tool superposed onto an externally driven fluid flow to enhance the heat transfer capacity of the system. In addition, EHD conduction mechanism is utilized as an effective tool to generate circulation flow inside reservoirs to effectively mix and thermally homogenize the liquid.
机译:电流体动力学(EHD)传导泵浦与电极附近有限厚度的杂化层相关,该杂化层是通过中性电解质物质的解离过程和生成的离子的重组过程生成的。这项理论和数值研究基于宏观,微米和纳米尺度的传导现象,提供了对电动液体流动的基本理解。还研究了EHD传导机理在增强热传递中的作用,这些应用涉及单相和具有相变的分层两相模型。在本研究的基础部分,建立了一个数值模型来研究电动液体和液膜流动。根据在各种操作条件下等温液膜的EHD传导泵送的可用实验测量结果对结果进行了验证。数值模型被进一步扩展,以包括由于液体蒸发或冷凝而引起的相变过程。进行了匹配的渐近分析,从宏观上研究了双电层和杂化层之间的相互作用。此外,研究了由于表面ζ电势的存在而引起的电动感应双层的影响以及该层与解离诱导的电荷层的耦合作用,以探讨这种耦合对微观结构中流动结构和体积流量的影响。 -和纳米级。最后,对经受双极性电荷解离的平行流进行线性稳定性分析,并重点关注其传热特性。观察到足够高的电荷离解会促进Poiseuille流动的不稳定性。;本研究的应用领域集中于利用EHD传导现象在地面和微重力的宏观和微观尺度上进行创新的主动传热增强技术。环境。应用范围从利用EHD作为唯一的泵送和增强机制到采用EHD传导作为叠加在外部驱动的流体流上以增强系统的传热能力的辅助工具。此外,EHD传导机制被用作有效工具,以在储液器内部产生循环流,从而有效地混合和热均化液体。

著录项

  • 作者

    Yazdani, Miad.;

  • 作者单位

    Illinois Institute of Technology.;

  • 授予单位 Illinois Institute of Technology.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 216 p.
  • 总页数 216
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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