Flow measurements in microporous media using micro-particle image velocimetry
Flow measurements in microporous media using micro-particle image velocimetry
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DOI：
10.1103/physrevfluids.3.104202
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发表时间：
2018-10
影响因子：
2.7
通讯作者：
Xianke Lu;Yuyuan Zhao;D. Dennis
中科院分区：
文献类型：
--
作者：
Xianke Lu;Yuyuan Zhao;D. Dennis
对微孔介质中的流型识别和孔洞尺度速度场的量化进行了实验研究。透明多孔介质是在两个载玻片之间去除大小为50μm的微晶玻璃微珠中的造孔剂，留下大小为500μm的典型孔洞而制成的。同时进行了压降测量和粒子图像测速仪测量，以评估基于孔径的流型和流动行为，基于雷诺数从0.1到140。发现并提出了四种不同的区域，即前达西、达西、福奇海默和湍流。研究了各流区时均速度的空间分布和特征，以及过渡区和湍流区的脉动强度。用速度测量和压降测量确定了临界雷诺数，结果吻合得很好，为转变提供了直接证据。研究了孔隙率对流动特性的影响，并与文献中的流型边界进行了比较。这些数据提供了对具有不同孔隙率的微孔介质中流动特性的洞察和更好的理解，可以进一步利用这些数据来增强微孔介质的流动和传热性能。研究还表明，速度和压力联合测量是研究微孔介质的一种有效方法。
An experimental study focused on the identification of the flow regimes and quantification of the velocity field at pore scale in microporous media is presented and discussed. Transparent porous media are fabricated by removing a pore forming agent in slightly sintered glass beads of size 50 μ m between two glass slides, leaving typical pores with a size of 500 μ m . Pressure-drop measurements and particle image velocimetry measurements are conducted simultaneously in order to evaluate the flow regimes and flow behaviors at pore size based Reynolds numbers from 0.1 to 140. Four different regimes, pre-Darcy, Darcy, Forchheimer, and turbulent, are found and presented. Spatial distribution and characteristics of the time-averaged velocity in all regimes and fluctuation intensity in transitional and turbulent regimes are investigated. Critical Reynolds numbers are identified using both velocity and pressure-drop measurements and the results agree very well, providing direct evidence underpinning the transition. The effects of porosity on these flow properties are also studied, and finally the flow regime boundaries are compared with the literature. These data provide an insight into the flow properties in microporous media with various porosities and an improved understanding that could be further utilized to enhance the flow and heat transfer performance of microporous media. It also demonstrates that velocity and pressure measurements used in combination can be an effective method for studying microporous media.