Using a unique, near-field microscopy technique, fringe patterns and nanoparticle motions are visualized immediately following a nanofluid droplet deposition on a glass substrate in which an air bubble is entrapped. The nanofluid consists of DI-water, 0.10% Aluminum Oxide nanoparticles with an average diameter of 50 nm, and 0.0005% yellow-green polystyrene fluorescent particles of 1 μm diameter...

In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid ...

Application of nanofluid and coiled tubes are two passive methods for increasing the heat transfer. In the present study, the turbulent flows of water and nanofluid in coiled tubes heat exchanger were numerically studied. CuO-water nanofluid containing 1 vol% copper oxide nanoparticles was used and single-phase approach was considered for nanofluid flow. The effect of different geometrical para...

This study numerically investigates heat transfer augmentation using water-based Al₂O₃ and CuO nanofluids flowing in a triangular cross-sectional duct under constant heat flux in laminar flow conditions. The Al₂O₃/water nanofluids with different volume fractions (0.1%, 0.5%, 1%, 1.5%, and 2%) and CuO/water nanofluids with various volume fractions (0.05%, 0.16%, 0.36%, 0.5%, and 0.8%) are employ...

In this paper a new equation for calculating the nanofluid viscosity by considering the Brownian motion of nanoparticles is introduced. The relative velocity between the base fluid and nanoparticles has been taken into account. This equation presents the nanofluid viscosity as a function of the temperature, the mean nanoparticle diameter, the nanoparticle volume fraction, the nanoparticle densi...

nanofluid is a new class of heat transfer fluids engineered by dispersing metallic or non-metallic nanoparticles with a typical size of less than 100 nm in the conventional heat transfer fluids.this article aims to investigate the overall and convection heat transfer coefficient and nusselt number of al2o3-water nanofluid flowing in a horizontal double pipe heat exchanger under turbulent flow (...

sometimes the need for non-circular ducts arises in many heat transfer applications because of lower pressure drop of non-circular cross section such as square duct compared to circular tube, particularly in compact heat. but square cross section has poor heat transfer performance and it is expected that using a nanofluid as a new heat transfer media may improve the heat transfer performance of...

the present work is an experimental study of steady state convective heat transfer of de-ionized water with a (0.04% by volume) volume fraction of al2o3 nanoparticles dispersed to form a nanofluid that flows through an aluminium tube.laminar fully developed flow heat transfer coefficient of al2o3 nanoparticles are dispersed in water in circular tube is discussed in this paper. in order to valid...

This paper presents a numerical study of heat transfer to turbulent and laminar Cu/water flow over a backward-facing step. Mathematical model based on finite volume method with a FORTRAN code is used to solve the continuity, momentum, energy and turbulence equations. Turbulence was modeled by the shear stress transport (SST) K–x Model. In this simulation, three volume fractions of nanofluid (0%...

Dynamic viscosity values for three particular water-based nanofluids have been experimental determined using a commercial ‘piston-type’ viscometer. Viscosity data, expressed as a function of temperature and particle volume fraction, are presented for 29nm particle-size CuO-water and Al2O3-water with 36nm and 47nm particle-sizes, temperatures up to 75°C and particle volume fraction up to 9%. In ...