The effect of utilizing superhydrophobic walls on improving the convective heat transfer in a rectangular heatsink has been studied numerically in this paper. The vertical walls were kept at isothermal hot-and-cold temperatures and horizontal walls were insulated. The boundary condition on the walls was: no-slip for regular, and slip (with slip length of 500 µm) for superhydrophobic walls. By c...

In the present study, an experimental study is carried out to investigate the effect of adding Al and Cu nanoparticles to the base fluid (water) on the heat transfer rate in a spirally coiled tube. The spirally coiled tube is fabricated from the straight copper tube with the inner and outer coil diameters of 100 and 420 mm, respectively. The experiments have been done for water and two types of...

Helical coil heat exchangers are widely used in industrial applications ranging fromcryogenic processes, air-conditioning, and nuclear reactors to waste heat recovery due totheir compact size and high heat transfer coefficient. In this kind of heat exchangers, flowand heat transfer are complicated. This paper reports a numerical investigation of theinfluence of different parameters such as coil...

We report a novel boiling heat transfer (NBHT) in reduced graphene oxide (RGO) suspended in water (RGO colloid) near critical heat flux (CHF), which is traditionally the dangerous limitation of nucleate boiling heat transfer because of heater failure. When the heat flux reaches the maximum value (CHF) in RGO colloid pool boiling, the wall temperature increases gradually and slowly with an almos...

Effect of time dependent normal transpiration on the problem of unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite circular cylinder moving simultaneously with time-depended angular and axial velocities and with time-dependent wall temperature or wall heat flux are investigated. The impinging free stream is steady with a strain rate . A re...

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 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...

the presence of particles in liquid-solid fluidized beds enhances the bed heat transfer, because the movement of the particles leads to an increased turbulence in the system. moreover, the violent movement of the particles has a positive effect on fouling of the heat transfer surface. the aim of this investigation was to perform systematic measurements of bed voidage and heat transfer coefficie...

The effect of imposed magnetic field on natural convection in a tilted cavity with partially active walls was investigated numerically. The active part of the right side wall was at a higher temperature than the active part of the left side wall and were moving on vertical walls relative to each other. The top, the bottom and the remaining parts of the side walls were insulated. The magnetic fi...

in this study, flow field and heat transfer of al2o3-cu/water micropolar hybrid nanofluid is investigated in a permeable channel using the least square method. the channel is encountered to chemical reaction, and a constant magnetic field is also applied. the bottom wall is hot and coolant fluid is injected into the channel from the top wall. the effects of different parameters such as the reyn...