Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Laminar Flow

A Comparison Between Sinusoidal Oscilation and Constant Temperature Boundary Conditions In Annulus Filled With Porous Media Saturated With Nanofluid

Manal H. AL; Hafidh

Engineering and Technology Journal, 2014, Volume 32, Issue 4, Pages 831-848

A numerical study has been carried out to investigate the heat transfer by natural convection of nanofluid taking copper as nano particles and the water as based fluid in a three dimensional annulus enclosure filled with porous media between two horizontal concentric cylinders with 12 annular fins of 3mm length and 2.4 mm thickness attached to the inner cylinder under steady state condition and different wall temperature boundary conditions. The governing equations which used are continuity, momentum and energy equations under an assumptions used Darcy law and Boussinesq’s approximation which are transformed to dimensionless equations. The finite difference approach is used to obtain all the computational results using the MATLAB- 7. The parameters affected on the system are modified Rayleigh number (10 ≤Ra*≤ 500), radius ratio Rr (0.293, 0.365 and 0.435) and the volume fraction . The results show that, increasing of fin length decreases the heat transfer rate and for Ra*<100, decreasing Rr cause to decrease Nu and adding Cu nanoparticles with φ= 0.35 cause 27.9% enhancement in heat transfer. A correlation for Nu in terms of Ra, Hf and φ, has been developed for inner hot cylinder.

Numerical Simulation of Buoyancy- Driven Laminar Flow Through An Air –Filled Isosceles Triangular Enclosure With A Differentially Heated Side Walls And An Adiabatic Bottom Wall

Ahmed Kadhim Hussein; Salam Hadi Hussain

Engineering and Technology Journal, 2010, Volume 28, Issue 10, Pages 2054-2069

Thermal And Flow Fields Due To Laminar Free Convection In An Isosceles
Triangular Enclosure Having Thick Conducting Sidewalls Have Been Investigated
Computationally. Inclined Left And Right Side Walls Are Maintained At
Isothermal Hot And Cold Temperatures Respectively While The Bottom Wall Is
Considered Adiabatic. Problem Has Been Analyzed And The Non-Dimensional
Governing Equations Are Solved Using Finite Volume Approach And Employing
More Nodes At The Fluid–Solid Interface. Triangular Enclosure Is Assumed To
Be Filled With An Air With A Prandtl Number Of 0.7. Rayleigh Number Varies
From 103 To 106 Where The Flow And Thermal Fields Are Computed For Various
Rayleigh Numbers. Consequently, It Was Observed That The Stream Function
And Temperature Contours Strongly Change With High Rayleigh Number. The
Streamline And Isotherm Plots And The Variations Of The Average Nusselt
Number At The Hot Left And The Cold Right Side Walls Are Also Presented. The
Results Explained A Good Agreement With Another Published Results.