摘要
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0.5~1mPa·s.实验雷诺数范围为Re＜8．所用有机液体为:四氯化碳、乙基苯及环己烷都是非极性液体,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．
The micro-scale flow's behavior has attracted great interest of the scientific researchersof the Micro-Electro-Mechanical-Systems (MEMS). As the flow characteristic length approachesto the intrinsic one of fluid medium, it is an open question that if macro scopic fluid flow ruleskeep valid. For gas flows, the Knudsen number linking these two characteristic lengths, has beenregarded as the criteria from continuous theory to free-molecule flow: Kn < 10-2 is for continuousflow 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 whetherthe intrinsic characteristic length of liquid and the nondimentional number, like Kn, is suitablefor 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 needsimprovement, but also from unawareness of fundamental facts in micro-flows. So it's valuable to dofurther in depth research. This paper presents at first the micro-flow experimental apparatus. Itspressure range was from 0 to 1 MPa with a high-pressure gas source, the experimental temperaturevaried in the range of 10°C^40°C and the flow rates were measured indirectly with displacementmethod. The error were analyzed, including the error resulted by the unsteady influence of thedisplacement of the liquid free surface. Under this experimental condition, the main error wasresulted in the measuring of the microtube's diameter. Non-ion water and several organic liquidsthrough a microchannel with diameter near 25μm were investigated. Flow rates and pressure dropwere measured. The experimental Reynolds numbers were smaller than 8, the liquid molecularweights vary from 18 to 160, their viscosity are 0.5~1mPa.s. The flow rates varied linearly withpressure drop. It means that the flow behaviors are in agreement with the conventional theory in theHagen-Poiseuille flow. As all the organic
出处
《力学学报》
EI
CSCD
北大核心
2002年第3期432-438,共7页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家基础研究发展规划课题(G1999033106)
国家攀A项目资助.
