Investigation on liquid thermal conductivity of ethylene glycol (EG)/water mixtures: A comparative experimental and molecular dynamics simulation study

Abstract

Ethylene glycol (EG) and water mixtures can be used as the antifreeze, refrigerant and coolant due to their good environmental, thermodynamic and transport performance. The mixture’s accurate thermal conductivity is indispensable for the optimal design of the relevant heat exchangers. However, thermal conductivity of EG/water mixtures is lacking and is seen to limit the further industrial application. In this paper, the transient hot wire method (THW) was used to measure the thermal conductivities of five EG/water mixtures (with ethylene glycol mass fraction wEG = 0, 0.25, 0.50, 0.75, 1.00) in the temperature range from 253.15 K to 353.15 K and pressures up to 8.0 MPa. A comparison was made between the present experimental data and literature values, yielding a good agreement. The AADs are within 2.65% for EG/water mixture systems. For convenience of engineering calculations, the present experimental data were correlated as a function of temperature and pressure. The average absolute deviations (AADs) between the experimental thermal conductivities and the calculations are 0.50%, 0.10%, 0.60%, 0.40% and 0.32% for mixture systems with ethylene glycol mass fraction wEG = 0.00, 0.25, 0.50, 0.75, 1.00, respectively. In addition, non-equilibrium molecular dynamics was applied to study the thermal conductivities of ethylene glycol/water binary mixtures based on PCFF (polymer consistent force field) and SPC/E (extended simple point charge) model, showing a good agreement with the experimental data. This study can provide fundamental thermal conductivity data for the heat transfer application of ethylene glycol aqueous solution in the industrial field.