Thermophysical Properties of Ethylene Glycol Dispersed with Al2O3 Nanoparticles for Solar Thermal Applications

Abstract

This study focuses on investigating the effects of adding Aluminium oxide (Al₂O₃) nanoparticles in ethylene glycol with emphasis on thermal conductivity and heat transfer enhancement. Alumina (Al₂O₃) nanoparticles after surface modification with a surfactant cetrimonium bromide (CTAB) were dispersed at concentrations of 1, 0.5, 0.25, and 0.125 mass percentages in ethylene glycol. The thermal conductivity and dynamic viscosity with different concentrations are evaluated, and through these properties, the heat transfer efficacy of of nanofluids is evaluated indirectly using a figure of merit called Mouromtseff number (Mo). The stability of suspension dispersed with CTAB is found to be excellent and the nanofluids could remain stable for one month. The addition of Al₂O₃ nanoparticles to ethylene glycol leads to a significant improvement in thermal conductivity, ranging from 15% to 25%. The Mouromtseff number (Mo) indicates that in turbulent flow, dilute nanofluids with low concentrations are the most efficient heat transfer medium.