Parametric analysis and optimal air velocity selection in forced air pre-cooling: effects of packaging quantity

Abstract The rapid removal of field heat from fruits and vegetables is essential for extending their shelf life. Existing optimization approaches for forced-air pre-cooling typically focus on individual packages, neglecting the influence of the packaging quantity ( N ) on cooling performance. This study developed a three-dimensional CFD model to investigate the impact of N on the forced-air pre-cooling of stacked produce. The results show that increasing N or reducing air velocity ( u ) prolongs the seven-eighths cooling time (SECT), with u having a more significant effect. Temperature inhomogeneity, due to the high conductive thermal resistance of apples, evolved in two stages: an initial increase followed by a decrease, and was more pronounced at larger N . By comprehensively analyzing SECT, fan energy consumption, and average temperature inhomogeneity, the optimal package quantity N was determined to be between 2 and 3.