The Viscosity Of Water In The Micron-scale Quartz Tubes

Viscosity is a fundamental parameter that characterizes the fluidity of fluids.Traditionally,the viscosity of water in porous media is treated as a constant value.But the fact is that the viscosity of water confined in micron-scale pores of porous media is exceptionally complex.In this paper,quartz tubes with different diameters are used to characterize the pores of porous media,and the viscosity measurement of water in quartz tubes with different diameters,the relationship between viscosity and density of water,and the influence of variable viscosity on water flow are studied.The main achievements of the paper are as follows:(1)The variation pattern of water viscosity in quartz tubes with diameter was obtained.Generally,the viscosity of water in quartz tubes decreases with increasing quartz tube diameter,but high viscosity values were measured at the lowest density point of 200 μm.(2)An empirical model was established to correspond the relationship between the density and the viscosity of the ordered water in quartz tubes,and the validity of previous densityviscosity empirical formulas was demonstrated.The comparative study shows that the studied viscosity-density model of ordered water in quartz tubes has better applicability.(3)Under the condition of non-constant density and viscosity,the generalized Newton’s law of internal friction is substituted into the equation of motion of viscous fluid expressed in terms of stress,and the equation of motion of pipe flow with radial variation of viscosity with pipe diameter is derived based on coordinate transformation and flow field boundary conditions.