Dufour and Soret Effects on Square Porous Annulus

N Nik-Ghazali,A Badarudin,Irfan Anjum Badruddin,S Tabatabaeikia

doi:10.1155/2014/209753

Abstract

A study on heat and mass transfer behaviour on porous medium embedded in a square annulus is conducted. The inner surface wall is considered to have a cool temperature T c while the outer surface is exposed to a hot temperature T h. Finite element method (FEM) is used to solve the governing partial differential equations. The results present the influences of the Dufour and Soret effects on the heat and mass transfer of a square annulus. The effects of various physical parameters on the temperature and concentration profiles together with the local Nusselt and Sherwood numbers are presented graphically. It is found that when Dufour parameter is increased, Nusselt number increases. Dufour effect has more influences on velocity profile, while it has no significant effect on the concentration and can be deemed negligible. It is observed that the local Nusselt number is highest at the bottom wall for low values of Dufour parameter; however, the top wall Nusselt number is highest for higher values of Dufour parameter. Soret effect tends to make more significant contribution to the concentration profile than Dufour effect.

Highlights

The enormous interest in the double diffusive convection in the recent years has led researchers to an extensive study on this topic due to its applicability in the industry as well as in engineering fields
Similar methodology was adopted to investigate the heat transfer in different geometries subjected to the thermal equilibrium as well as thermal nonequilibrium approach which provides fundamental and helpful information to understand the complex phenomena of heat transfer in porous medium [14,15,16,17,18,19,20]
When Dufour parameter is increased to D = 1, the bottom wall has an overall higher Nusselt number than the other walls

Summary

Introduction

The enormous interest in the double diffusive convection in the recent years has led researchers to an extensive study on this topic due to its applicability in the industry as well as in engineering fields. Alam and Rahman [26] have included Soret and Dufour effects in their studies on the mixed convection flow past a vertical porous flat plate They concluded that the effect by thermal and concentration gradient affects the flow field appreciably. Postelnicu [32] studied heat and mass transfers influenced by magnetic field and included the Soret and Dufour effect He used natural convection flow for vertical surfaces. The present study emphasizes the Soret and Dufour effect in case of the square annulus fixed with porous medium inside, subjected to the outside heating The various parameters such as the buoyancy ratio, aspect and radius ratios, Lewis and Rayleigh numbers, and radiation parameter were discussed in detail

Analysis

Numerical Method

Results and Discussion

Conclusion

H: Height of cylinder k: Thermal conductivity kt Thermal diffusion ratio