Flow boiling in microchannels has received considerable attention from researchers worldwide in the last decade. A scaling analysis is presented to identify the relative effects of different forces on the boiling process at microscale. Based on this scaling analysis, the flow pattern transitions and stability for flow boiling of water and FC-77 are evaluated. From the insight gained through the...

abstract: in this paper, a new population-based search called the bees algorithm (ba) is presented to estimate the time-dependent heat transfer coefficient and the corresponding heat flux at the boundaries of a two-dimensional body subjected to transient heat conduction, using the temperature measurements at discrete nodal locations on the boundaries, where heat flux is specified as the boundar...

Two-phase heat transfer is experimentally examined through vertical small diameter tubes, D =1.45 and 2.8 mm using water under a pressure of 50 to 81 kPa and a natural circulation condition. The pool boiling correlation by Stephan-Abdelsalam and the thermosyphon boiling correlation by Imura, et al. predict the measured experimental data in the 2.8 mm tube with an error of -30%. A large heat tra...

Precision droplet manufacturing (PDM) is a process that builds complex 3D parts one nano-liter molten metal droplet at a time from a CAD file without the need for tooling. One method to control the droplet temperature when it arrives at the target is to heat the droplets in-flight. This note describes such a heater that uses helium and nitrogen as the convective heat transfer medium. Heating ra...

A three-dimensional numerical study was made to investigate effects of fin angle, fin surface emissivity, and tube wall temperature on heat transfer enhancement for a longitudinal externally-finned tube placed vertically in a small chamber. The numerical model was first validated through comparison with experimental measurements and the appropriateness of general boundary conditions was examine...

The potential of nanofluids for the improvement of heat transfer coefficient in various heat exchangeequipment has been considered and studied as a major application during recent decades. In this research,heat transfer coefficient of ZnO, TiO2 and ZnO/TiO2 nanofluids in a shell and tube heat exchanger has beenstudied experimentally. ZnO nanoparticle was synthesized through pre...

Within this paper the convective heat dissipation from the front brake discs fitted to the left and right hand side of a high performance passenger car has been compared. The tools used in this investigation include computational fluid dynamics (CFD) and vehicle testing. The results show that although identical discs are fitted to both sides of the vehicle the disc fitted to the left hand side ...

The study scrutinizes the effect of convective heating on magnetohydrodynamic (MHD) stagnation point flow and heat transfer of upper-convected Maxell fluid p ast a s tretching s heet i n t he p resence o f n anoparticles. T he m odel u sed i n t he s tudy i ncludes t he e ffect o f B rownian m otion and thermophoresis parameters. The non-linear governing equations and their boundary conditions ...

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...