牛顿流体全黏度范围黏度测量的理论与实验

Theory and Experiment for Viscosity Measurement of Newtonian Fluids in Full Viscosity Range

为解决表面光散射法在临界振荡区测量偏差较大的问题,探索该方法应用于全黏度牛顿流体黏度测量的途径。修正表面光散射小角度仪器加宽效应,考虑气液界面表面波在近临界振荡区体相耗散效应,建立可以精确刻画牛顿流体全黏度范围的表面波频域色散方程,利用离散快速傅里叶变换将获得的时域相关数据转化为频域数据,并开发了多元频域拟合算法,以确保在任意黏度范围可以精确获得其黏度和表面张力值,并能给出统计学意义的不确定度。本研究提供了一种绝对的、全黏度范围牛顿流体黏度测量的表面光散射理论、方法和系统。

This study is conducted to solve the problem of large measurement errors in the critical oscillation region by the surface light scattering method and explore the ways to apply this method to measure the viscosity of Newtonian fluids in the full viscosity range.To this end,we correct the instrumental broadening effect of small angles in surface light scattering and establish the frequencydomain dispersion equation of surface waves that can precisely describe the full viscosity range of Newtonian fluids considering the dissipation effect of the bulk phases of surface waves at the gasliquid interface in the nearcritical oscillation region.The discrete fast Fourier transform is adopted to transform the timedomain correlation data into the frequencydomain data.A multivariate frequencydomainbased fitting algorithm is developed to ensure the accurate determination of the viscosity and surface tension in any viscosity range and give the uncertainty of statistical significance.This study provides the absolute viscosity measurement theory,method,and system of surface light scattering for fullviscosityrange Newtonian fluids.