One way to increase the heat transfer is to use perforated twisted tapes with different hole diameters, which largely improve heat transfer with an increase in the heat transfer area at the constant volume and more mixed flow. In the previous studies, the effect of nanofluids with perforated twisted tapes is less studied. In this work, the performance of water / iron oxide nanofluid in a double...

Abstract   An empirical investigation was carried out to study convective heat transfer of nanofluid flow inside an inclined copper tube under uniform heat flux condition. Required data are acquired for laminar and hydrodynamically fully developed flow inside round tube. The stable CuO-base oil nanofluid with different nanoparticle weight fractions of 0.5%, 1% and 2% was produced by means of ul...

Critical Heat Flux, or CHF, is an important condition that defines the upper limit of safe operation of heat transfer equipment employing boiling heat transfer in heat flux controlled systems. Although significant research has been conducted in this field, a clear understanding of the basic mechanisms leading to the CHF condition is still lacking. The present article covers the subcooled flow b...

-Deterioration in heat transfer at supercritical water cooling in a vertical pipe is numerically analyzed. The calculation is based on a parabolic solver for steady-state equations in r-z two dimensions, a Ice model for turbulence and a steam table library for physical properties of supercritical water. Calculation results agree with the experimental data of Yamagata et al. It is found that hea...

The excellent performance of fluidized bed heat exchangers is due to the interaction between particles and heat transfer surface and to the mixing effects in the viscous sublayer. In this paper, the results of experimental investigations on heat transfer for a wide range of Newtonian and non-Newtonian (shear-thinning power law) fluids are presented. New design equations have been developed ...

  In this numerical study the the heat transfer and laminar nanofluid flow in the three-dimensional microchannels with triangular cross-section is simulated. For increase the heat transfer from the walls of the channel, semiattached & offset mid- truncated rib,s Placed in the canal, and the tooth geometry and the impact is studied. In this study, the water is base fluid, and the influence of th...

A numerical study has been performed to analyze the wall heat transfer mechanisms during growth of a vapor bubble inside a microchannel. The microchannel is of 200 lm square cross section and a vapor bubble begins to grow at one of the walls, with liquid coming in through the channel inlet. The complete Navier-Stokes equations along with continuity and energy equations are solved using the SIMP...

in the presented research, heat transfer of a mobile electrolyte alkaline fuel cell (afc) (which the electrolyte has cooling role of system) has been considered. proper control volumes of system with specific qualification have been chosen. consequently, heat and mass transfer in control volumes have been assessed. considerations on them and contributed models lead to approve a double tube heat...

high temperatures are often encountered in almost all of the combustion systems, therefore, thermal radiation heat transfer can influence the droplets heat up rate and consequently their life time. in this paper, the effect of thermal radiation heat transfer is investigated for two cases of directional and spherically symmetric illuminations. the flow and temperature fields insdie and outside o...

The present study attempts to improve heat transfer efficiency of a domestic gas burner by enhancing heat transfer from flue gases. Heat transfer can be augmented using the obstacles that are inserted into the flow field near the heated wall of the domestic gas burner. First, to achive the maximum efficiency, the insert geometry is optimized by the multi-objective genetic algorithm so that heat...