摘要
用PDMS加工了5个宽2mm、深100μm、长4cm的微通道,其内部充满方形排列的微柱群形成多孔介质模型,采用微流体粒子图像测速仪(Micro-PIV)获得该多孔介质内速度场的分布,在此基础上计算了剪切应力,得到剪切应力场分布及其均方根.实验结果表明,速度分布具有较好的对称性,符合低雷诺数条件下的流动规律.速度值沿展向呈现类谐波的周期性变化规律,不同流向位置的速度幅值不同.靠近圆柱壁面的对称位置存在两条流线,其上流速保持不变.由剪切应力分布可看到近壁区存在较大速度梯度,剪切强度与雷诺数成正比,与孔隙率的三次方呈近似反比关系.
Five microchannels with 2mm width,100μm depth and 4cm length,which were filled with square arrays of micro cylinders to form porous medium models were processed by PDMS materials.The microscale particle image velocimetry(Micro-PIV)was used to measure the velocity field.The shear stresses were calculated based on the measured velocities;and shear stress fields and their root-mean-square(RMS)were obtained.The results show that the velocity distributions have good symmetry,which are in accordance with the flow characteristics of low Reynolds numbers.Transverse velocities show quasi-harmonic periodic variations;and they have different values of amplitude on different streamwise locations.Two streamlines exist in the symmetric positions near the micro-cylinder wall,where the velocities are constant.It can be seen from the shear stress distribution that the velocity gradients are large near the wall surface of micro-cylinders.The shear strength is proportional to the Reynolds number and inversely proportional to the third power of porosity approximately.
出处
《中国计量学院学报》
2013年第4期387-392,共6页
Journal of China Jiliang University
基金
国家自然科学基金资助项目(No.11172287)
浙江省高等学校中青年学科带头人学术攀登项目
