FINITE ELEMENT SOLUTION OF HYDROMAGNETIC MIXED CONVECTION IN A NANOFLUID FILLED VENTED GROOVED CHANNEL

Mohammad Mokaddes Ali̇,Syed Sabbir Ahmed,Md Abdul Alim Ali̇m

doi:10.18186/thermal.843866

Abstract

The mixed convection flow in a differentially heated grooved channel filled with water based nanofluid under the influence of external magnetic field has been analyzed numerically in this study. Nanofluid’s thermal conductivity model has been modified to develop a new physical problem and finite element method has been implemented to solve the dimensionless governing equations. Numerical simulations have been performed for different values of pertinent parameters. Fluid flow and temperature distributions have been exhibited in terms of streamlines and isotherms due to the variation of Richardson number, Hartmann number and concentration of nanoparticles in base fluid water. The results show that flow field and temperature distributions within the channel affected significantly with the effects of Richardson number, Hartmann number and concentration of nanoparticles. In addition, it is found that heat transfer rate increases and decreases respectively with the increase in strength of magnetic field which depends strongly on Richardson number. Moreover, heat transfer rate accelerates effectively for increasing volume fraction, Reynolds number and Richardson number. The present simulation has been validated by comparing the present results with other published works on the basis of special cases.

Highlights

The mixed convection heat transfer in presence of external magnetic effects in closed or open enclosures were studied by many researchers because of its industrial and engineering applications including heat exchangers, cooling of electronic devices, heating and cooling system in building, solar collectors, nuclear reactors, chemical processing equipments, liquid metals, crystal growth, geothermal reservoirs, thermal insulations, drying technologies and other industrial processes etc
The efficiency of such thermal systems is closely related to the heat transfer mechanisms
Different techniques are used to improve the efficiency of heat transfer mechanisms

Summary

INTRODUCTION

The mixed convection heat transfer in presence of external magnetic effects in closed or open enclosures were studied by many researchers because of its industrial and engineering applications including heat exchangers, cooling of electronic devices, heating and cooling system in building, solar collectors, nuclear reactors, chemical processing equipments, liquid metals, crystal growth, geothermal reservoirs, thermal insulations, drying technologies and other industrial processes etc. Ahmed et al [25] utilized finite volume method to investigate numerically the thermal and flow fields characteristics for laminar steady mixed convection flow in a square lid-driven enclosure filled with water-based micropolar nanofluids and found that enhancement of average Nusselt number depends on the length of heat source and solid volume fraction. Magnetohydrodynamic mixed convection of hybrid nanofluid flow in a horizontal channel was numerically studied by Hussain et al [36] Their results highlighted that the mixed convection mode and rate of heat transfer increased with increasing Richardson number and decreased for magnetic effect. Ali et al [42] numerically analyzed the effect of magnetic field on natural convection flow and heat transfer properties in a grooved enclosure filled with nanofluid Their results indicated that the heat transfer rate increases with the increase in Rayleigh number and solid volume fraction of nanoparticales but decreases for increasing strength of magnetic field.

Re P r

RESULTS AND DISCUSSION

CONCLUSION