SECOND LAW ANALYSIS OF MIXED CONVECTION OF MAGNETOHYDRODYNAMIC FLOW IN AN INCLINED SQUARE LID-DRIVEN ENCLOSURE

Elif Büyük Öğüt

doi:10.18186/thermal.655023

Abstract

Second law of thermodynamics analysis is formulated for the case of laminar mixed convection in an inclined square lid-driven enclosure in the presence of magnetic field. Vertical sides of the enclosure moves upward when inclination angle is zero. Governing equations of flow and temperature in the form of stream function-vorticity formulation were solved numerically using the differential quadrature method. Governing parameters are: Richardson number (from 0.01 to 100), Prandtl number (from 0.1 to 1.0), inclination angle of enclosure (from 0 to 180), Hartmann number (from 0 to 100) and magnetic field direction (0). It is found that the inclination angle of enclosure is effective parameter on entropy generation especially for higher Richardson number (Ri > 1) due to domination of natural convection. However, Hartmann number is effective on both heat transfer and entropy generation for all values of Richardson and Prandtl numbers and it decreases the convective fluid flow and entropy generation.

Highlights

Flow fields and temperature distributions in lid-driven cavities are important for both thermal sciences and fluid mechanics due to their importance in areas such as cooling of electronic devices, geothermal applications, furnaces, air-solar collectors etc
Flow fields, temperature distributions and heat transfer rates and results for entropy generations are examined for different Richardson numbers, inclination angle of the enclosure, Hartmann and Prandtl number
The results were presented as streamlines, isotherms, Nusselt numbers, contours of entropy generation due to heat transfer irreversibility, contours of entropy generation due to fluid friction irreversibility and Bejan number

Summary

INTRODUCTION

Flow fields and temperature distributions in lid-driven cavities are important for both thermal sciences and fluid mechanics due to their importance in areas such as cooling of electronic devices, geothermal applications, furnaces, air-solar collectors etc. Chamkha [10] made a numerical analysis to obtain flow and temperature field of hydromagnetic combined convection flow in a lid-driven enclosure with left side moves up/down with internal heat generation or absorption. They solved the governing equations based on finite-volume approach along with the ADI scheme. Laminar, mixed convection flow under the presence of a magnetic field in an inclined square enclosure with isothermally heated and moving side walls, and stationary and adiabatic horizontal walls was considered. The volumetric entropy generation rate for a two-dimensional flow in Cartesian coordinates can be defined as [11]:

Ecx Pr

RESULTS AND DISCUSSION

CONCLUSIONS

Stream function