Investigation of free convection and entropy generation inside an enclosure with a corrugated wall

Abstract

The graphical behavior of laminar natural conve.ction of an incompressible and Newtonian fluid in an enclosure are studied by using Computer Aided Fluid Flow Analysis (CAFFA). Hydrodynamic and thermal behavior of fluid along with heat transfer irreversibility inside two isothermally heated surfaces are predicted. The lower surface is flat plate which is kept hot and the upper plate is a wavy surface which is kept cold. Two vertical plates are considered adiabatic. The mathematical formulation of the problem considered in terms of continuity, momentum, and the energy equations, and the pertinent boundary conditions for a wavy domain containing one wavy upper wall and three flat walls. For two-dimensional laminar natural convection, the non-dimensional equations governing the conservation of mass, momentum and energy in the enclosure are used. Finite-volume method is used to discretize the governing differential equations with nonstaggered variable arrangement. Second law of thermodynamics is applied to predict the nature of irreversibility in terms of entropy generation. TDMA solver is used to solve the algebraic equations. Time integration is done using three time level method. Iteration is continued until the difference between two consecutive field values of variables is less than or equal to 10-5 Time dependent simulations are performed for several Reynolds number. Rate of heat transfer in terms of local and global Nusselt numbers are calculated for different Rayleigh numbers. Flow and thermal fields are analyzed by parametric presentation of streamlines and isothermal lines.