Modeling and Simulation of Temperature Fields in the Process of Pressure-Difference Precooling of Loquats in Multiple Rows of Cartons

Abstract

Experiments were carried out to verify the design for loquat precooling, including the air supply velocity, the shape of air vents and the piling of cartons, so as to create valuable theoretical reference. Five-layer corrugated cartons for loquats were used in the study, and the methodologies adopted include computational fluid dynamics, unsteady shear pressure and the SST k-ω model. Under the same initial conditions and boundary conditions, different parameters were compared in theory and verified through experiment, including temperature field distribution among multiple rows of cartons, cooling time, average rate of cooling and uniformity. Results: the temperature changes observed in experiments tally with modeling results, which validates the theoretical model. The precooling of multiple rows of loquat cartons is not a simple superposition of multiple cooling processes for cartons positioned in one row. 2.5m/s is an ideal rate of air supply velocity. For multiple rows of cartons, circle vents would improve the uniformity, while runway circle vents induce hot spots. Therefore, for loquat precooling, it is highly recommended to use flat cartons with circle vents and to position the cartons in less rows.