A numerical approach to estimate the thermophysical properties and convective heat transfer characteristics of Al2O3/R600a nanorefrigerant

Abstract

Different experimental studies showed that the inclusion of nanoparticles into pure refrigerant leads to improved thermal properties and thereby better performance and energy savings of refrigerators compared to conventional refrigerant systems. This paper intends to explore the thermophysical, rheological and convective heat transfer properties of Al2O3/R600a (alumina/isobutane) nanorefrigerant at several temperatures and volume fractions (1 to 5 %) of Al2O3 nanoparticles. Additionally, convective heat transfer coefficient is also studied by varying the mass flux of the nanorefrigerant flowing through a smooth tube. Obtained results show that thermal conductivity, density, viscosity and convective heat transfer coefficient of the nanorefrigerant increase while specific heat and Nusselt number decrease with the increase in volume fraction of nanoparticles at any fixed temperature. Moreover, thermal conductivity, specific heat, Nusselt number and convective heat transfer coefficient exhibit a rising trend, whereas density and viscosity show the opposite trend with the increase in temperature.