in this paper, turbulent mixed convective heat transfer of water and al2o3 nanofluid has been numerically studied in a horizontal tube under non-uniform heat flux on the upper wall and insulation in the lower wall using mixture model. for the discretization of governing equations, the second-order upstream difference scheme and finite volume method were used. the coupling of pressure and veloci...

The buoyancy-driven boundary-layer flow from a heated horizontal circular cylinder immersed in a water-based alumina (Al2O3) nanofluid is investigated using variable properties for nanofluid viscosity. Two different viscosity models are utilized to evaluate heat transfer enhancement from a cylinder. Exact analytic solutions of the problem are attained employing a novel...

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 article presents an experimental investigation on effects of morphology of nanoparticles on the viscosity nanofluids (nfs). water and ethylene glycol were used as base fluids. a two step method was used for preparation of nfs. sio2 nanoparticles, cnt and graphene nano sheets were dispersed in the base fluids separately with the volume fraction ranging from 0.05% to 1.5%. stability of the n...

in the present work the effect of cu-water nanofluid, as heat transfer fluid, on the performance of a parabolic solar collector was studied numerically. the temperature field, thermal efficiency, mean-outlet temperatures have been evaluated and compared for the conventional parabolic collectors and nanofluid based collectors. further, the effect of various parameters such as fluid velocity, vol...

in this paper, convection heat transfer of al2o3-water nanofluid turbulent flow through internally ribbed tubes with different rib shapes (rectangular, trapezoidal and semi-circular) is numerically investigated. for each rib shape, the optimum geometric ratio and volume fraction were calculated using entropy generation minimization technique. the governing equations in steady state and axisymme...

in this work, the steady and laminar mixed convection of nanofluid in horizontal concentric annulus withrotating inner cylinder is investigated numerically. the inner and outer cylinders are kept at constanttemperature ti and to respectively, where ti>to. the annular space is filled with alumina-water nanofluid.the governing equations with the corresponded boundary conditions in the polar coord...

Homogeneous and stable magnetic nanofluids containing γ-Fe2O3 nanoparticles were prepared using a two-step method, and their thermal transport properties were investigated. Thermal conductivities of the nanofluids were measured to be higher than that of base fluid, and the enhanced values increase with the volume fraction of the nanoparticles. Viscosity measurements showed that the nanofluids d...

natural convection heat transfer has many applications in different fields of industry; such as cooling industries, electronic transformer devices and ventilation equipment; due to simple process, economic advantage, low noise and renewed retrieval. recently, heat transfer of nanofluids have been considered because of higher thermal conductivity coefficient compared with those of ordinary fluid...

Liquid paraffin as a coolant fluid can be  applied in electronic devices as a result to its suitable capabilities such as electrical insulating, high heat capacity, chemical and thermal stability, and high boiling point. However, the poor thermal conductivity of paraffin has been confined its thermal cooling application. Addition of high conductor nanoparticles to paraffin can fix this drawback...