【摘要】 采用电解质溶液离子输运的Nernst-Planck方程、液体运动的Navier-Stokes方程和电场的Poisson方程研究了微扩散管的双电层、电解质流动电位势和电黏性效应。采用有限体积法分析了微扩散管流动电位势、流动电阻力、流量损失和流动速度形态变化。结果表明,与均匀截面微通道不同的是,流动电位势在微扩散管内呈非线性增长,流动电阻力沿微通道截面扩张方向下降。在微扩散管的横截面上也会产生流动电位势和电阻力。在微收缩管流动的电黏性效应和流量损失率比微扩散管流动略大。论文数值解给出流动电位势从瞬态到稳态发展过程的时间尺度特征,并分析了微通道扩散角对电黏性效应产生的微通道流量损失率。更多还原

【Abstract】 Using Nernst-Planck equation for ion transport of electrolyte solution,Navier-Stokes equation for liquid flows and Poisson equation for electric field,electric double layers,flow-induced streaming potential and electro-viscous effects in a finite micro-diffuser were studied. Finite element method was used to investigate streaming potential,electric resistance of flow,flow rate loss and velocity profile variation in micro-diffuser. The results indicate that in contrast to a section-uniform microchannel,the streaming potential grows non linearly,the electric resistance of flow decreases in micro-diffuser. Streaming potential and electric resistance of flow creates in cross-section of channel. The electroviscosity of flow and flow rate loss in narrowing direction is slightly larger than in expanding direction of micro-diffuser. The numerical solutions represent time evolution behavior of streaming potential from transient state to steady state. The effect of expan-ding angle of the micro-diffuser on flow rate loss due to electro viscosity is also analyzed.更多还原