低速非线性流动特性的实验研究

Experimental research on nonlinear flow characteristics at low velocity

实验研究了去离子水在内径为5μm和2μm微圆管中的流动特性,并回归得到了边界层水膜厚度随剪切力的变化公式。实验结果表明,典型牛顿流体去离子水在5μm和2μm微圆管中表现出不同程度的非线性流动特性,管径越小,其非线性流动特性越强;微圆管的视渗透率不是常数,而是随压力梯度的增大而增大并最终趋于理论值;有效流动横截面积随压力梯度增大而增大;边界层是导致低速非线性流动特性的主要因素之一。

The flow characteristics of deionized water in microtubes with diameters of 5 μm and 2 μm were investigated experimentally. And the equation of thickness variation of water film with shear stress was regressed. The experimental results indicate that typical Newtonian fluid deionized water shows different nonlinear flow characteristics in microtubes with diameters of 5 μm and 2 μm. Moreover, the smaller the diameter is, the more positive the nonlinear flow characteristics are. The apparent permeability of microtubes increases gradually to a theoretical value with pressure gradient increasing. The effective flow cross-section also increases with pressure gradient increasing, And the boundary layer is one of the main factors which results in the nonlinear flow characteristics.