A VARIABLE-POROSITY POROUS MEDIUM MODEL OF TRANSIENT COMBINED CONVECTION AIR COOLING OF APPLES IN BOXES

摘要

Cool storage is of the utmost importance for the quality preservation of horticultural products. A proper design of the cooling process requires knowledge of the complex heat transfer phenomena involved. An analysis of the transient temperature response of apples in bins during cooling is presented based on a porous medium two-phase modelling approach. The small container-to-apple-diameter ratio requires a variable-porosity model. A numerically stable and cost-effective model is developed to predict the three-dimensional transient air flow and temperature distributions of both air and solid phases. The model accounts for natural and forced convection, apple respiration and container geometry for different air velocity conditions. Heat transfer and flow resistance correlations are incorporated in the model.