作　　者： ; ;

机构地区： 中国科学院广州能源研究所

出　　处： 《高校化学工程学报》 2009年第3期397-403,共7页

摘　　要： 在微尺度下,由于流动处于层流状态,因此混合是一个巨大的难题。针对微尺度混合的特点,提出了一种新型微混合器。这种微混合器利用入口速度方波型脉动实现微通道内流体的有效混合。针对物理问题建立了通用的无量纲方程和边界条件,利用计算流体动力学(CFD)方法研究了微混合器的特性和脉动参数的影响。结果表明在脉动方波占空比为0.5,相位差为180度时,能达到较好的混合效果。当雷诺数为1.0,脉动频率为2Hz时,混合度能达到79%。研究表明:微混合器中流动具有混沌对流特征,脉动流动可极大地增加界面面积,从而实现快速混合。综合各参数的影响建立了参数-脉动体积,当其未超过混合通道体积时,其值越大,混合效果越好。 Since the flow in microfluidic system is always in laminar manner, mixing in it is a challenging issue. Based on the characteristics of liquid mixing in micron scale, a new micromixer was proposed. Using pulsating velocities in the form of square wave at the entrances of the mixer, effective mixing could be achieved According to the physical principles of micro-mixing, the dimensionless equations and boundary conditions for micro-mixing were established. The numerical simulation demonstrates that good mixing performance could be obtained when the duty cycle of pulsing is equal to 0.5 and the phase delay is equal to 180 degrees. Especially, the degree of mixing can reach 79% for Re=l.0 and f=2 Hz. The study shows that the flow in the micromixer possesses the characteristics of chaotic advection and the pulsating flow can significantly increase the interface area of the two fluids, which causes the rapid mixing. Synthesizing the effects of parameters on micromixing, an important parameter, i.e. pulsating volume, was identified. The mixing performance is better for the micromixer with larger pulsating volume as long as it does not surpass the volume of the mixing channel.

关 键 词： 计算流体动力学 微混合器 混沌对流 脉动流动

领　　域： [化学工程] [理学] [理学]