Abstracts: Nanofluids, as a kind of new engineering material consisting of nanometer-sized additives and base fluids. The nanoparticles used in nanofluids are typically made of metals, oxides, carbides, or carbon nanotubes. Common base fluids include water, ethylene glycol and oil. As in the conventional cooling fluid, due to its low heat transfer coefficient the heat transfer capacity of the fluid is very less, when the nano particles are added in the base fluid in particular volumetric percentage of the base fluid, the heat transfer coefficient of the mixture (Nanofluid) is increases. Thus it has higher heat transfer rate for same physical conditions. The aim of the review is to analyze the different properties of the base fluid and nanofluid at different volume concentration and compare them experimentally.
A nanofluid is a fluid that contains particles of nanometric size, called nanoparticles. These fluids are designed colloidal suspensions of nanoparticles in a base fluid. Nanoparticles used in nanofluids are typically made of metals, oxides, carbides or carbon nanotubes. Common base fluids include water, ethylene glycol and oil.
Nanofluids have novel properties that make them potentially useful in many applications in heat transfer, including microelectronics, fuel cells, pharmaceutical processes and hybrid engines, engine cooling / thermal management of the vehicle, household refrigerator, cooler, heat exchanger in grinding, machining and in reducing the temperature of the combustion gases of the boiler. They present higher thermal conductivity and the convective heat transfer coefficient compared to the base liquid. [6] Knowledge of the rheological behavior of nanofluids is very critical in deciding their suitability for convective heat transfer applications. Nanofluids also have special acoustic properties and in ultrasonic fields show an additional cut-off reconversion of an incident compression wave; the effect becomes more pronounced as the concentration increases.
In the analysis, such as computational fluid dynamics (CFD), it can be assumed that nano-fluids are monophasic fluids. However, almost all of the new academic paper uses two-stage hypotheses. The classical theory of single-phase fluids can be applied, where the physical properties of nano-fluid are taken as a function of the properties of both constituents and their concentrations. An alternative approach simulates nano-fluids using a two-component model.
The dispersion of a nano-fluid droplet is enhanced by the solid ordering structure of nanoparticles assembled near the diffusion contact line, which results in a structural disintegration pressure in the vicinity of the contact line. However, such an improvement is not observed for small droplets with nanoscale diameter, because the wetting time scale is much smaller than the diffusion time scale.