| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 94 === The electrokinetic flow of an electrolyte solution through a microchannel which comprises a bundle of cylinders is investigated for the case of constant surface potential. The system under consideration is simulated by a unit cell model, and analytical expressions for the flow field and the corresponding residence time distribution under various conditions are derived. These results are readily applicable to the assessment of the performance of a microreactor such as that comprises a bundle of optical fibers. Numerical simulations are conducted to investigate the influences of the key parameters, including the thickness of double layer, the strength of applied electric field, the magnitude of applied pressure gradient, and the characteristic sizes of a microchannel, on the residence time distribution. We show that the followings could result in a shorter residence time: thin double layer, strong applied electric field, large applied pressure gradient, and small number of cylinders. Based on the thickness of double layer, criterions are proposed for the judgment of whether the flow field can be treated as a laminar flow or as a plug flow, two basic limiting cases in reactor design.
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