微管道内液体低速流动的实验研究 Experimental Study on Liquid Flow in Microtubes under Low Velocity Condition

研究微尺度条件下的液体流动规律对于高效开发低渗透油气资源有着重要意义。本文实验研究了低速条件下去离子水和正十六烷在内径分别为18.5 μm、9.6 μm和4.1 μm的石英微圆管内的流动特性。实验结果显示当流速范围在0.01 mm/s~1 mm/s时，微管道内的液体压降与平均流速呈线性关系，微圆管内的实际流动阻力与经典流体力学的层流流动理论基本吻合，该结果说明对于直径大于4 μm的微管道内的牛顿流体流动，固壁不动边界层的影响可以忽略，并没有出现流动阻力随着流速降低而减小的达西非线性现象以及明显的启动压力现象。 The research on the liquid flow at micro-scale is of great significance to develop low permeability oil/gas reservoirs at high efficiency. In this paper, the flow characteristics of de-ionized water andn-Hexadecane flowing through quartz microtubes with inner diameter of 18.5 μm, 9.6 μm and 4.1μm were investigated in experiments. The experimental results show that the pressure drop has linear relationship with average velocity of the fluid in the microtubes. The experimental friction factor is consistent with the classical laminar flow theory when the flow velocity ranges in 0.01 mm/s - 1 mm/s, which indicates that the influence of the stationary boundary layer could be neglected when the diameter of the microtube exceeds 4 μm. The nonlinear Darcy phenomenon that the flow resistance increases as the reduction of flow rate and the obvious phenomenon of the starting pressure do not occur for the Newton fluid flow in microtubes.