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

Abstract

Natural convection heating within a can of liquid food during sterilization is simulated by solving the governing equations for continuity, momentum and energy conservation for an axisymmetric case using a commercial Computational 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, were 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 migrate 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 velocity was found to be in the range of 10 −5–10 −4 m/s for CMS and of 10 −2–10 −1 m/s for water, these magnitudes of course vary with time and position in the can. The time required for the SHZ to reach the sterilization temperature of 100°C was 1800 s for CMC and only, 150 s for water.