ABSTRACT
This chapter provides an overview of the physicochemical and thermo-physical characteristics of nanofluids. The applications of nanofluids are discussed to provide in-depth understanding in this area. Homoaggregates are often seen in nanofluids prepared in laboratory conditions; while heteroaggregates often occur in nanofluids obtained in practical conditions. To prevent the agglomeration of nanoparticles in nanofluids, sonication and/or mechanical stirring followed by the addition of a stabilizing agent are performed. The state of dispersion and stability of nanofluids depends on the properties of the solid material dispersed and of the base fluid, such as morphology, chemical structure, interaction, and the pre-treatment. The efficacy of nanofluids depends on various characteristics such as thermal conductivity, density, viscosity, specific heat, heat capacity, and the interaction with the surrounding environment in which the heat transfer takes place. Heat and mass transfer capacities of fluids are yet another aspect that determines the suitability of fluids for process engineering.
