电渗驱动微流道内流场的数值模拟

Numerical Simulation of Electroosmotic Flow in Microchannels

针对微流道中电场和流场耦合的问题,建立了电渗流的数学模型,应用有限元法对微流道内的速度分布进行了稳态和瞬态的数值模拟。研究了电场强度、溶液浓度和微流道高度等因素分别对微流动速度在空间和时间上的影响规律。结果表明,在电渗驱动下,微流道中的流体流动呈现"塞状"流型,流动速度与电场强度及微流道表面静电势成正比,而与微流道的高度无关。微流体由开始运动到稳态的过度时间的尺度为毫秒量级,大小与微流道高度比值的平方成正比,而与电场强度和溶液浓度无关。研究结果为电渗驱动在微流控芯片中的应用提供了理论依据。

Aiming at the coupling problems of electrical potential field and flow field in microchannel, the mathematical models of electroosmotic flow were made, and numerical simulation of steady state and transient state based on finite element method was proposed. The influence of electric field, ionic concentration and scales of microcharmel to velocity in spatial and time was analyzed. The results show that velocity distribution of microflow is ＂plug-like＂ microflow rate is proportion to the electrical field strength and zeta potential, while irrelevant with the height of the microchannel. The scale of steady time of microflow is microsecond, and the magnitude is proportion to the square of ratio of height of the microchannel, while irrelevant with the electric field strength and ionic concentration. The results provide the references for the application of electroosmotie driven in mierofluidic chips.