Numerical simulation of natural convection heating of canned food by computational fluid dynamics

Natural convection heating within a can of liquid food during sterilization is simulated by solving the governing equations for continuity, momentum a nd energy conservation for an axisymmetric case using a commercial Computat ional Fluid Dynamics (CFD) package (PHOENICS). Transient flow patterns and temperature profiles within model liquids (sodium carboxy-methyl cellulose (CMC) and water) have been predicted. The model liquids, CMC and water, wer e assumed to have constant properties except for the viscosity (temperature dependent) and density (Boussinesq approximation). It has been shown that the action of natural convection forces the slowest heating zone (SHZ) to m igrate towards the bottom of the can as expected. The shape and the size of the SHZ area are different for CMC and water. The magnitude of the axial v elocity was found to be in the range of 10(-5)-10(-4) m/s for CMS and of 10 (-2)-10(-1) mis for water, these magnitudes of course vary with time and po sition in the can. The time required for the SHZ to reach the sterilization temperature of 100 degrees C was 1800 s for CMC and only, 150 s for water. (C) 1999 Elsevier Science Ltd. All rights reserved.