Analysis of heatlines and entropy generation during free convection within trapezoidal cavities

In this article natural convection flows have been studied within trapezoidal cavities where left wall of the cavity is hot and right wall is maintained at constant cold temperature while the top and bottom walls are adiabatic. The results are presented in terms of streamlines, heatlines, isotherms, entropy generation due to fluid friction, entropy generation due to heat transfer, average Bejan number, total entropy generation and average Nusselt number. It may be concluded that, the trapezoidal cavity with φ = 60° is the optimal shape for thermal processing at Pr = 0.015 whereas square cavity (φ = 90°) is the optimal design for the thermal processing at Pr = 7.2 based on lower Stotal and higher Nul¯.