一种基于金属环液膜力学分析的液体密度、表面张力的现场测量方法

Experimental study on simultaneous measurement of liquid density and surface tension coefficient

液体密度与表面张力系数等物理参数准确、快速地测量在日常生活及工业生产中都具有重要意义.现有的同时测量密度和表面张力系数的方法对测量条件要求较为苛刻,无法满足现场测量要求.本文提出了一种通过一次采样同时测量液体的密度与表面张力系数的方法.该方法首先利用高精度、高频率力传感器连续测量出金属环在液面下降过程所受拉力随时间的变化,进而在对金属环出液过程中的受力进行详细分析的基础上对不同阶段的数据的拟合分别得出了液体的密度和表面张力系数.借助该方法分别测量了自来水、氯化钠溶液、无水乙醇三种液体的密度与表面张力系数.结果显示该方法在1 Hz测量频率下,对密度和表面张力系数的测量结果与标准值的差异分别在7.30%与2.76%以内.该方法的原理简单,测量时间较短,对测量环境的要求相对较低,具有应用在工业现场的潜力.

Accurate measurement of physical parameters such as liquid density and surface tension coefficient is of great significance in real life and industrial production. The existing methods of measuring density and surface tension coefficient at same time have strict requirements on measuring conditions and cannot meet the requirements of field measurement. This paper proposes a method for simultaneously measuring the density and surface tension coefficient of a liquid with one sampling. This method firstly uses a high-precision, high-frequency force sensor to continuously measure the tension of the metal ring during the liquid level drawdown, then processes a detailed force analysis to metal ring, further obtains the density and surface tension coefficient of the liquid by fitting the different part of data. The density and surface tension coefficient of tap water, 12% sodium chloride solution and absolute ethanol alcohol were measured by this method. The results show that the difference between the measured value and the standard value for density and surface tension coefficient are within 7.30% and 2.76% respectively in 1 Hz measuring frequency. This method has a simple principle, a short measurement time and a low requirement for the measurement environment. It shows potential for application in industrial filed.