Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : finite difference


An Investigation of Natural Convection Heat Transfer in a Square Enclosure Filled with Nanofluid

Ayad M. Salman

Engineering and Technology Journal, 2011, Volume 29, Issue 12, Pages 2346-2363

In this research, numerical solution of natural convection heat transfer of nanofluids in two-dimensional square enclosures is obtained for different values of Rayleigh numbers and volume fraction of nanofluids. Numerical simulation has then been undertaken for the mixture of Cu-water as nanofluid. The stream–vorticity form of the Navier–Stokes equations and energy equation are used in this study. The present model is utilized to obtain results in the range of Rayleigh number 103–105 and volume fractions of nanofluids (0.025-0.1). The enclosure which represent two-dimensional square enclosure with heated left side wall, while the right side was cold, the top and bottom walls were adiabatic. The governing equations are solved with finite-difference technique by central difference scheme. A computer program in (FORTRAN 90) was used to carry out the numerical solution. The results are a remarkable increase in the average Nusselt number with an increase in the volume fraction. An increase in the Rayleigh number results an increase in the average Nusselt number for a certain nanoparticle. In order to validate the numerical model, the results of two previous works for square enclosure filled by water based Al2O3 nano-particles as nanofluids. The first work was variation of average Nusselt number and volume fraction for Ra number Ra=103. There are excellent agreement in results and the maximum difference between these results reach 4.2%. A relation between average Nusselt number and Ra number also compared for other previous work. There are agreement in results and found the maximum difference between results reach to 6.5% approximately at Ra=105 which validate the present computational model.

An Investigation of Natural Convection Heat Transfer in a Square Enclosure Filled with Nanofluid

Ayad M. Salman

Engineering and Technology Journal, 2011, Volume 29, Issue 11, Pages 2216-2233

In this research, numerical solution of natural convection heat transfer of nanofluids in two-dimensional square enclosures is obtained for different values of Rayleigh numbers and volume fraction of nanofluids. Numerical simulation has then been undertaken for the mixture of Cu-water as nanofluid. The stream–vorticity form of
the Navier–Stokes equations and energy equation are used in this study. The present model is utilized to obtain results in the range of Rayleigh number 103–105 and volume fractions of nanofluids (0.025-0.1). The enclosure which represent twodimensional square enclosure with heated left side wall, while the right side was cold,
the top and bottom walls were adiabatic. The governing equations are solved with finite-difference technique by central difference scheme. A computer program in (FORTRAN 90) was used to carry out the numerical solution. The results are a remarkable increase in the average Nusselt number with an increase in the volume fraction. An increase in the Rayleigh number results an increase in the average Nusselt number for a certain nanoparticle. In order to validate the numerical model,
the results of two previous works for square enclosure filled by water based Al2O3 nano-particles as nanofluids. The first work was variation of average Nusselt number and volume fraction for Ra number Ra=103. There are excellent agreement in results and the maximum difference between theses results reach 4.2%. A relation between
average Nusselt number and Ra number also compared for other previous work. There are agreement in results and found the maximum difference between results reach to 6.5% approximately at Ra=105 which validate the present computational model.

Evaluation of Elastic Deflections and Bending Moments for Orthotropically Reinforced Concrete Rectangular slabs Supported on Three Edges Only

Hisham M. AL-Hassani; Husain M. Husain; Aama; a Ali Ahmad

Engineering and Technology Journal, 2009, Volume 27, Issue 7, Pages 1247-1259

This paper deals with the evaluation of the elastic deflections and bending moments
for orthotropically reinforced concrete rectangular slabs supported on three variously
restrained edges with the fourth edge free and subjected to uniformly distributed load.
Six cases are considered for such slabs to cover all possible restraining conditions at the
three supported edges. Based on the finite difference approach, equations are derived to
calculate the maximum values of the positive and negative bending moments as well as
the maximum deflection in any of these six slab cases caused by the applied uniform
load.