齿形微通道内流流场数值模拟及试验研究

以断面尺寸800μm×800μm的齿型微通道为研究对象,在雷诺数为100和300流动条件下对微通道内流进行试验测量和数值模拟.利用Micro-PIV技术,获取了微通道内流流场速度矢量分布图和流线图,试验结果发现微通道内流在各齿之间流动结构具有重复性,齿内流场包含高速区和低速区,且低速区在转向内侧和左顶角区域存在回流,内附一个完整的涡旋.数值模拟采用多孔介质模拟微通道壁面粗糙元、配合realizable k-ε湍流模型的数值模拟方法,对微通道几何结构单齿建模,利用周期性边界条件模拟计算得到了微通道内流流场分布,模拟流场与试验结果特征相同;在微通道内流特定截面上进行流速定量分析,分析结果为模拟值与试验值吻合程度高,证明该模拟方法在较大雷诺数范围内均适用于复杂结构的微通道内流流动模拟计算.

Numerical simulation and experiment for velocity field in jagged micro-channel

Under Re of 100 and 300 respectively,the flow field distributions in jagged micro-channel with side lengths of 800 μm were investigated by experimental measurement and numerical simulation.Applying micro-PIV technique,the research got the velocity vector distributions and streamline graphs of the flow field.The results show that the flow structures are the same in each gear of the micro-channel.It has high-speed zone and low-speed zone in the flow field of single gear,and the backflow appears in the flat top and corner with a complete vortex in the low-speed zone.A novel numerical method for simulating micro-scale flow field was established mainly by adopting porous medium model,realizable k-ε turbulence model,and single gear geometric model setting.The flow field distributions in the micro-channel are got by simulating and calculating under periodic boundary conditions.The simulation flow fields are consistent with the experimental results.Through the quantified analysis on the specific cross section,it proves that the simulation value and experimental value have a high degree of similarity,and the numerical simulation approach can be used in all the inflow velocity simulation for the complex structured micro-channels with a wider range of Reynolds.