in this investigation the silicate nano structure of mcm-41 has been used for the production of nanofluid.the particles have negligible heat conductivity and therefore by their dispersion in a base fluid likewater, it is possible to study the increase of heat conductivity due to the brownian motion effects. in thiswork a suitable apparatus for the measurement of heat conductivity has been built...

using of nanofluids and ducts with corrugated walls are both supposed to enhance heat transfer, by increasing the heat transfer fluid conductivity and the heat transfer area respectively. use of a diverging duct with a jet at inlet section may further increase heat transfer by creating recirculation zones inside the duct. in this work two-dimensional incompressible laminar flow of a nanofluid e...

the main purpose of this study is to perform numerical simulation of nanofluids as the coolant in vver-440 fuel rod bundle. the fuel rod bundle contains 60 fuel rods with length of 960 mm and 4 spacer grids. in vver-440 fuel rod bundle the coolant fluid (water) is in high pressure and temperature condition. in the present thermo-hydraulic simulation, water-al2o3 nanofluids containing various vo...

This paper investigates the enhancement of heat transfer coefficient and Nusselt number of a nanofluid containing nanoparticles (γ-AL2O3) with a particle size of 20 nm and volume fraction of 0.1%-0.3% (V/V). Effects of temperature and concentration of nanoparticles on Nusselt number changes and heat transfer coefficient in a double pipe heat exchanger with counter turbulent flow are investigate...

In this paper, mixed convection of Al2O3-EG-Water nanofluid in a square lid-driven enclosure is investigated numerically. The focus of this study is on the effects of variable thermophysical properties of the nanofluid on the heat transfer characteristics. The top moving and the bottom stationary horizontal walls are insulated, while the vertical walls are kept at different constant temperature...

Convective heat transfer of MgO-water nanofluid in a microchannel heat sink is experimentally investigated in various concentrations of 0.01, 0.05, 0.1, and 0.6 wt%. The microchannel consisted of 48 parallel rectangular cross section channels with the height of 800 µm, width of 524 µm and length of 52 mm. A well stability duration (ca. 1 month) was resulted by a 180 min ultra-sonication of the ...

The forced convective heat transfer (CHT) coefficient of a particular nanofluid, Al2O3 nanoparticles-ethylene glycol (EG) mixture, was investigated experimentally in a double-pipe heat exchanger. The nanofluid Nusselt number for different nanoparticles’ concentrations as well as various operating temperatures was measured to be increased up to 23.7% using 1.0% wt of nanoparticles. The significa...

The present work deals with the laminar natural convection in a square cavity with differentially heated side walls subjected to constant temperatures and filled with homogenous 0,4 wt. % aqueous solution of carboxymethyl cellulose (CMC) based Au, Al2O3, Cu and TiO2 nanofluids obeying the Power law rheological model. The governing differential equations have been solved by the standard finite v...

Nanofluids are engineered colloidal suspensions of nanoparticles in water, and exhibit a very significant enhancement (up to 200%) of the boiling Critical Heat Flux (CHF) at modest nanoparticle concentrations (50.1% by volume). Since CHF is the upper limit of nucleate boiling, such enhancement offers the potential for major performance improvement in many practical applications that use nucleat...

This paper presents a theoretical investigation of the second law performance of double diffusive forced convection in microreactors with the inclusion of nanofluid and radiation effects. The investigated microreactors consist of a single microchannel, fully filled by a porous medium. The transport of heat and mass are analysed by including the thick walls and a first order, catalytic chemical ...