A review of nanofluid preparation, stability, and thermo-physical properties

This paper represents a comprehensive review on the preparation and stability of nanofluid, the convective heat transfer coefficient and different thermo-physical properties such as thermal conductivity, specific heat capacity, viscosity, and so on. Here, for each thermo-physical property, measurement methods, enhancement mechanisms, and criticisms of different studies are also presented. However, based on the available literature, it is concluded that a nanofluid has, in general, better thermo-physical properties even at a very low particle concentration (typically 1% or less) than conventional heat transfer fluids. The only drawback is high viscosity which leads to a higher pressure drop. At a very low particle concentration, this drawback can be minimized. Three tables are provided for three thermo-physical properties namely thermal conductivity, specific heat capacity, and viscosity, which can be used as a ready reference for calculating the nanofluid properties.