The attractive force between the nanoparticles can cause them to aggregate. Therefore, nanoparticles have to be dispersed by different methods, in order to utilize their unique material characteristics completely. This study aims to use the self-developed nanofluids synthesis system to produce a Cu-based nanofluid with good suspension stability and particle dispersion. Parameters such as peak c...

A modern concept for solar thermal collectors is based on volumetric absorption of sunlight, where nanoparticles suspended in liquids directly receive the incident radiation. Suspending nanoparticles in traditional fluids can drastically enhance their optical properties and improve thermo-physical performances, thus leading to highly efficient volumetric solar receivers. Several studies have be...

thermal and radiative properties. Such work has generated great controversy, although it is arguably accepted today that the presence of nanoparticles rarely leads to useful enhancements in either thermal conductivity or convective heat transfer. On the other hand, there are still examples of unanticipated enhancements to some properties, such as the reported specific heat of molten salt-based ...

graphene oxide was prepared using modified hummers method. stable ethylene-glycol nanofluids containing graphene oxide nanosheets were provided. nd: yag pulsed laser was applied to prepare reduced nanofluids. experimental results revealed that thermal conductivity of the nanofluids is increased with increasing the concentration of graphene oxide (go) in ethylene glycol. the enhancement ratio of...

A comprehensive model has been proposed to account for the large enhancement of thermal conductivity in nanofluids and its strong temperature dependence, which the classical Maxwellian theory has been unable to explain. The dependence of thermal conductivity on particle size, concentration, and temperature has been taken care of simultaneously in our treatment. While the geometrical effect of a...

An experimental study was conducted to investigate the structural stability of ethylene glycol-based titanium dioxide nanoparticle suspensions (nanofluids) prepared by two-step method. The effects of particle concentration, fluid temperature, shear rate and shear duration were examined. Particle size and thermal conductivity measurements in quiescent state indicated the existence of aggregates ...

for better understanding the effect of nanofluid flow in a porous medium, a set of experiments were conducted on a horizontal glass micromodel for al2o3-water nanofluids. to characterize the flow of nanofluids the same experiment was done by pure water. the glass micromodel was constructed by a photolithography technique. the al2o3-water nanofluids were produced by a two-step method and no surf...

The rheological behaviour of ethylene glycol-based nanofluids containing hexagonal scalenohedral-shaped α-Fe2O3 (hematite) nanoparticles at 303.15 K and particle weight concentrations up to 25% has been carried out using a cone-plate Physica MCR rheometer. The tests performed show that the studied nanofluids present non-Newtonian shear-thinning behaviour. In addition, the viscosity at a given s...

The mass fraction of 0.01 wt% ZnO nanofluid was prepared via the two-step method. measurement verifies that nanofluids have better transmission characteristics in frequency division window range 400–1200 nm. At same time, it has good absorption ultraviolet and near-infrared bands, which meets application conditions spectral beam-splitting module PV/T system. A system designed. simplified physic...

In this experimental work, ZnO nanoparticles were synthesized using the chemical precipitation method, and nanoparticle structure morphology characterized through XRD SEM. Heat transfer exergetic characteristics then studied in a shell tube heat exchanger PGW-based nanofluids varying volume concentration nanofluid (shell side) flow rate at 6, 8, 10 12 litres/min. The hot water was fixed results...