Li Fengyi, Shi Shaoyi, Ma Weigang, Zhang Xing
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China.
Rev Sci Instrum. 2019 Jul;90(7):075105. doi: 10.1063/1.5064426.
A method involving a vibrating hot wire is proposed for measuring the viscosity and thermal conductivity of liquids. A platinum wire is bent into a semicircular shape and immersed in the sample liquid in the presence of a static magnetic field. Alternating current is then applied to the wire, causing it to vibrate and generate heat. At low frequency, the frequency response of the vibration is used to calculate the viscosity. At high frequency, the vibration amplitude of the wire is less than the molecular free path, and the thermal conductivity of the sample is obtained from the temperature dependence of the resistance. The proposed method is validated using water, toluene, anhydrous ethanol, and ethanediol as the test samples. The measurement uncertainty is estimated to be 1.5% (k = 1) for thermal conductivity and 0.7% (k = 2) for viscosity.
提出了一种涉及振动热线的方法来测量液体的粘度和热导率。将铂丝弯成半圆形，并在存在静磁场的情况下浸入样品液体中。然后向该丝施加交流电，使其振动并产生热量。在低频时，利用振动的频率响应来计算粘度。在高频时，丝的振动幅度小于分子自由程，并且根据电阻的温度依赖性获得样品的热导率。使用水、甲苯、无水乙醇和乙二醇作为测试样品对所提出的方法进行了验证。热导率的测量不确定度估计为1.5%（k = 1），粘度的测量不确定度估计为0.7%（k = 2）。
