Comprehensive investigation of corrugated fiberboard boxes with edge vents for ambient loading of chinese cabbage: Part I - Computational fluid dynamics simulation and experimental validation

The ambient (warm) loading of perishable products is widely practiced during their storage and transport. The vent hole design in a corrugated fiberboard box is crucial for providing effective airflow to maintain the freshness of products during ambient loading. In this study, four different corrugated fiberboard boxes with vent hole areas of 0, 2, 3, and 4 % were prepared. The cooling behavior of the Chinese cabbage in the corrugated fiberboard boxes with different air vent holes was verified using a computational fluid dynamics (CFD) simulation model. The results indicated that the cooling rate of the Chinese cabbage in the top and bottom layers of the seven-layer box stacks decreased substantially faster than those in the middle layers of the boxes, regardless of the air vent hole areas. The experimental analysis indicated significant differences in the cooling rates of the Chinese cab-bages among the seven-layer box stacks with 0, 2, 3, and 4 % air vent holes; however, the CFD simulation exhibited no significant differences in the cooling rates of the Chinese cabbages among those stacks. The compression strength of the corrugated fiberboard box designed with a 4 % air vent hole area exhibited the lowest value, which was nearly 20 % lower than that of the box with 0 % air vent hole area. Moreover, highly humid conditions were observed in the headspace of boxes, which was a critical factor causing a further decrease in its mechanical property in addition to the inevitable reduction caused by the vent hole design. Thus, the study findings can form the scientific basis for improving the edge-vent corrugated fiberboard box design used for transporting Chinese cabbage by ambient loading.