Abstract:

Fluid flow in the microchannel is limited to the low Reynolds number regime. As a result, mixing of solutions with different concentrations in the microchannel is inherently diffusion dominated，requiring a long mixing channel and retention time to attain a homogeneous solution. In this paper the flow characteristics in the two-dimension closed-end microchannel electroosmotic flow were simulated，and the mixing efficiencies of the closed-end microchannel electroosmotic flow applying different electric field intensities were compared. The results showed that because of existing non-uniform induced back pressure，there were two annular flows in the whole closed-end microchannel，enhancing the convection effect and leading to a shorter mixing time and higher mixing efficiency.

摘要： 微通道内流体的雷诺数一般都比较低，不同浓度溶液之间的混合主要通过扩散来完成，因此需要较长的时间和距离才能混合均匀。本文数值模拟了二维闭口微通道内电渗流的流动特性，并比较了施加不同电场强度情况下，闭口微通道电渗流的混合效率。结果表明由于非线性诱导背压的存在，闭口微通道内产生了两个环形流动，增强了对流，可以有效地缩短混合时间，提高混合效率。