非极性小分子有机液体在微管道中的流量特性
Flow characteristics of non-polar organic liquids with small molecules in a microchannel
查看参考文献9篇
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文摘
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用去离子水及有机液体在内径约为25μm的石英圆管内进行了流量特性实验。液体分子量范围为18～160，动力黏性系数的范围为0.5～1 mPa·s。实验雷诺数范围为Re < 8。所用有机液体为：四氯化碳、乙基苯及环乙烷都是非极性液体，其分子结构尺度小于1nm。实验结果表明，在定常层流条件下，圆管内的液体流量与两端压力差成正比，其压力-流量关系仍符合经典的Hagen-Poiseuille流动。这说明非极性小分子有机液体在本实验所用微米尺度管道中其流动规律仍符合连续介质假设。鉴于微尺度流动实验的特殊性，文中还介绍了微流动实验装置，分析了微尺度流动测量误差来源及提高测量精度的措施。 |
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其他语种文摘
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The micro-scale flow's behavior has attracted great interest of the scientific researchers of the Micro-Electro-Mechanical-Systems (MEMS). As the flow characteristic length approaches to the intrinsic one of fluid medium, it is an open question that if macro scopic fluid flow rules keep valid. For gas flows, the Knudsen number linking these two characteristic lengths, has been regarded as the criteria from continuous theory to free-molecule flow: Kn < 10~(-2) is for continuous flow regime and Kn > 10 for free-molecule flow regime. But for liquid flows, unfortunately, understanding of micro-fluid mechanics is much less than that for gases. It's still unclear whether the intrinsic characteristic length of liquid and the nondimentional number, like Kn, is suitable for liquid as. Some recent experimental results in micro-scale flows show conflict phenomena. This is not only resulted from the difficulty of the micro-scale experimental technique which needs improvement, but also from unawareness of fundamental facts in micro-flows. So it's valuable to do further in depth research. This paper presents at first the micro-flow experimental apparatus. Its pressure range was from 0 to 1 MPa with a high-pressure gas source, the experimental temperature varied in the range of 10 ℃～40 ℃ and the flow rates were measured indirectly with displacement method. The error were analyzed, including the error resulted by the unsteady influence of the displacement of the liquid free surface. Under this experimental condition, the main error was resulted in the measuring of the microtube's diameter. Non-ion water and several organic liquids through a microchannel with diameter near 25 μm were investigated. Flow rates and pressure drop were measured. The experimental Reynolds numbers were smaller than 8, the liquid molecular weights vary from 18 to 160, their viscosity are 0.5～1mPa·s. The flow rates varied linearly with pressure drop. It means that the flow behaviors are in agreement with the conventional theory in the Hagen-Poiseuille flow. As all the organic liquids used are non-polar molecules and their molecular scales, like CCL_4, C_6H_5C_2H_5 and C_6H_(12), are smaller than 1 nm, the experimental results indicate that the N-S equation based on continuity medium still acts well for the low Re number flow in the microchannel under the present experimental conditions. |
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来源
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力学学报
,2002,34(3):432-438 【核心库】
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关键词
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微管道流动
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有机液体
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非极性液体
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微机械系统
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尺度效应
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地址
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1.
中国科学院力学研究所, 非线性力学国家重点实验室, 北京, 100080
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中国科学院化学研究所, 高分子物理和化学国家重点实验室, 北京, 100080
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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0459-1879 |
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学科
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力学 |
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基金
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国家973计划
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国家攀登计划项目
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文献收藏号
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CSCD:1013791
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参考文献 共
9
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