Experimental investigation of the effect of Al2O3 nanoparticles with spherical and rod-shaped morphologies on the thermophysical properties of ionic nanofluids

Ionic Liquid(IL)now refers to fluids that are liquid at temperatures above 100°C, they are called "Green"solvents.One of their applications is in heat transfer and solar collectors.Thermophysical properties can be improved by adding nanoparticles to the IL.For this reason,spherical and rod-shaped alumina nanoparticles were added to 1-Hexyl-3-methyl imidazolium hexafluorophosphate IL with different weight percentages. The effect of adding nanoparticles on thermophysical properties of IL such as density,viscosity,thermal conductivity, and heat capacity in 0.05,0.1 and 0.5 %wt of nanoparticles at temperatures of 20, 30, and 50 °C is investigated. Increasing the concentration of nanoparticle set out an increase in density, viscosity, and thermal conductivity and a decrease in the thermal capacity of the ionic nanofluid (INF) compared to the base IL.Also, the viscosity, density, and thermal conductivity in INF with rod-shaped alumina nanoparticles are improved more than spherical alumina nanoparticles. Also the experimental viscosity and thermal conductivity data were fitted with the existing theoretical models. the viscosity of spherical alumina-IL and rod-shape alumina-IL was in unison with particles aggregation effect (Krieger-Dougherty model) and the both INF effective thermal conductivity are prognosticated by interfacial layer approach with sufficient accuracy.Eventually nonlinear equations have also been proposed for changes in the thermophysical properties of viscosity.