Status of Enhanced Heat Transfer in Systems With Natural Refrigerants

Condensation Heat Transfer of Pure Refrigerants in Microfin Tubes

An Experimental Investigation of Convective Boiling Heat Transfer Using Alternative and Natural Refrigerants Inside Horizontal Microchannels

In present study, the two phase flow boiling heat transfer coefficient and pressure drop of R410A, R32 and R290 in microchannels are demonstrated. The experimental data were conducted in horizontal stainless steel tubes with the inner diameter of 0.3 mm and 1.5 mm. The testing conditions were performed with the mass fluxes range from 200 to 500 kg/m2s, the heat fluxes from 10 to 20 kW/m2, the s...

Enhancement of Natural Convection Heat Transfer in Annular Enclosures

Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105  to 5 x 106...

A Numerical Modeling for Natural Convection Heat Transfer in Porous Media With Generated Internal Heat Sources

In this paper a numerical method is used to study the unsteady state natural convection heat transfer within a confined porous media with uniform internal heat generation. The governing equations based on the Darcy model and Bossiness approximations are solved, using the finite difference Alternating Direction Implicit (ADI) method. The developed program was used to simulate natural convection ...

CFD analysis of natural convection heat transfer in a square cavity with partitions utilizing Al2O3 nanofluid

In the present study, natural convective heat transfer in a partitioned square cavity utilizing nanofluids is studied. The vertical left and right walls are considered as the hot and cold walls, respectively and the partitions assumed to be adiabatic. The nanofluid used in this study is Al2O3 with the volume fraction of 20%. It is assumed that nanofluid is a single phase f...