1,2-丙二醇/乙醇混合物液相导热系数的实验研究

Thermal conductivity of 1,2-propanediol and ethanol binary mixtures

乙醇和1,2-丙二醇是重要的化工原料,以其作为主要组分的多元低温载冷剂在低温工程技术中具有重要的应用价值。为了给1,2-丙二醇/乙醇混合物的工程应用和科学研究提供基本的热物性数据,在233—313 K的温度范围内,利用瞬态热线法测量装置对乙醇、1,2-丙二醇及摩尔分数分别为0. 2,0. 4,0. 6和0. 8的1,2-丙二醇/乙醇二元液相混合物的导热系数进行了实验研究。采用二阶Scheffé多项式,将混合物的导热系数实验数据拟合为温度和质量分数的关联方程,实验数据与关联方程的最大偏差和平均绝对偏差分别为0. 48%和0. 12%。利用5种二元液体混合物的导热系数预测方法对1,2-丙二醇/乙醇混合物的导热系数进行了估算,根据预测结果与实验值的偏差,从工程应用及方程形式上推荐使用幂率法对液体混合物的导热系数进行预测。

Ethanol and 1,2-propanediol,as important chemical raw materials in chemical synthesis and main components for low temperature refrigerant,showed great potential in cryogenic engineering.In this paper,the basic thermophysical data for engineering application and scientific research about the binary mixture of ethanol and 1,2-propanediol were studied.The experimental thermal conductivity data of ethanol,1,2-propanediol and their binary mixtures were measured using the transient hot-wire apparatus over the temperatures range from 233 to 313 K at atmospheric pressure,with four different mole fractions of ethanol and 1,2-propanediol of 0.2,0.4,0.6 and 0.8,respectively.The Scheffépolynomial equation was used to correlate the experimental data as a function of temperature and mole fraction.The maximum deviation and the average absolute deviation of the calculated values from the experimental data are 0.48%and 0.12%,respectively.Five different predictive models on thermal conductivity were applied to predict the binary system of ethanol and 1,2-propanediol.The deviations between predicted results and the experimental data show that the Power Law method is better in terms of engineering application and simplicity of the equation.