双毛细管法高温气态环己烷黏度测量研究

为了探索双毛细管法在碳氢燃料高温气态黏度测量中的应用，本文采用双毛细管法测量了亚临界压力下环己烷的高温气态黏度。测量温度范围：301.9 K-567.1 K（间隔约10K）；压力范围：0.5MPa-4.0MPa（间隔1.0 MPa）。考虑螺旋管圈的二次流效应，使用基于雷诺数（Re）或迪恩数（De）的函数关系式对黏度测量结果进行离心修正。在测量参数条件下，气态环己烷的雷诺数Re ≤ 1984.5。研究表明：双毛细管法测量环己烷液态和气态黏度时，螺旋管圈的二次流效应具有显著差别；液态环己烷的离心修正系数小于 4.32%，气态环己烷的离心修正系数最高达到 49%；离心力二次流效应是影响环己烷气态黏度测量精度的最重要因素；离心修正关系式的准确度对环己烷气态黏度测量结果的不确定度产生显著影响。

Viscosity Measurements for Gaseous Cyclohexane at High Temperature by Two-Capillary Method

In order to develop the application of two-capillary method on the viscosity measurement of gas hydrocarbon fuel at high temperature, the viscosities of gas cyclohexane were measured by the two-capillary viscometer at high temperature and subcritical conditions. The temperature ranged from 301.9 K to 567.1 K (about 10 K intervals) and pressure ranged from 0.5 MPa to 4.0 MPa (1.0 MPa intervals). Considering the secondary flow of fluid in the coils, the viscosity measurement results were modified by centrifugal correction coefficient as a function of Reynolds number (Re) or Dean number (De), and the Reynolds numbers (Re) were below 1984.5 in the measurements. The research indicated that the secondary flow effect in the coils differs significantly between the viscosity measurement of liquid and gas cyclohexane by two-capillary method. The centrifugal correction coefficients for viscosity measurements of liquid cyclohexane was less than 4.32%, for viscosity measurements of gas cyclohexane was up to 49%.Therefore, the second flow effect that results from centrifugal force is the most important factor affecting the measurement accuracy of the viscosity of gas cyclohexane, and the accuracy of the centrifugal function plays an important role on determing the uncertainties of measurement results of viscosity of gas cyclohexane.