NUMERICAL STUDY OF UNSTEADY 2D NATURAL CONVECTION AND SOLIDIFICATION OF A FOOD INSIDE A FREEZING CHAMBER

A numerical study for the conjugate analysis of unsteady natural convection and solidification during freezing of a rectangular food is presented. The SIMPLER finite volume method, with a nonuniform grid of 1575 nodes and nondimensional time steps of 2.5 = 10-4 was used to solve continuity, linear momentum, and energy equations for 104 <Ra <106. The effects of Rayleigh number on the freezing curves and on average Nusselt number on the chamber walls and on the food surfaces are described. Transient results for streamlines and isotherms show nonsymmetric characteristics of the air flow around the food.