微米管道液体流量测量的几个问题-中国力学学会.PDF

第六届全国实验流体力学学术会议 微米管道液体流量测量的几个问题 1 1 2 2 李战华 崔海航 徐征 王立鼎 (1 中国科学院力学研究所 非线性力学国家实验室（LNM ） 北京 100080) (2 大连理工大学 微系统中心 大连 116024) 摘要：本文详细介绍了微米管道中液体压力－流量特性测量实验的理论依据、实验方法及影响实验精度的 因素。通过对实验系统的不确定度分析，说明了流道几何尺寸的测量误差是影响实验精度的关键。对可能 影响实验的因素，例如液面蒸发、粘性热耗散、管壁滑移等问题，进行了分析并给出了相应的估算公式。 根据在 3~20µm 圆管和出口直径为 1~15µm 的锥形管道流量测量的结果，可以认为液体在20µm 以上微管 低压驱动下的流动特性与 Hagen-Poiseuille 理论预测相同，而高压驱动下的流动需要考虑液体黏性的 修正。液体在锥形管道中的流动则要考虑截面参数修正。 Abstract: The detailed introduction including the experimental principle, the experimental method and the factors taken into account in measurement precision of microflows is presented in this paper. Based on the analysis of the experimental uncertainty, the measurement accuracy of microtube diameters is obviously dominative to experimental precision. Several possible factors, for example, the evaporation on liquid/solid interface, viscous dissipation and wall slip are considered and the quantitative estimates are acquired. According to our previous experimental results in microtubes with 3~20µm diameters and micro nozzles with the exit diameter 1~15µm, it can be deemed that the flow characteristics driven by the lower pressure in microtubes with the diameter larger than 20µm agree well with the prediction from classical Hagen-Poiseuille theory, the viscous vs. pressure relationship should be considered under high pressures, and the change of characteristic dimension of cross section is taken into account in micro nozzle tests. 关键词：微米管道 液体 微流动 不确定度 Keywords: Microchannels, Liquid, Microfluidic, uncertainty 1 引言 微尺度流体力学是介于经典宏观流体力学与微观力学之间的研究领域，主要研究特征尺度在 cm 至 nm 范围内的流体流动规律[1,2]