CFD modelling to study the effects of table grape packaging and stacking on fruit cooling and moisture loss

Optimal packaging and storage are critical technologies in maintaining postharvest quality of fresh produce. Computational fluid dynamics (CFD) modelling was used to investigate the airflow, heat and mass transfer characteristics of packed table grapes during postharvest cooling and handling. The 3-D CFD model was applied to study the effects of packaging components and box stacking on the airflow, heat and mass transfer characteristics. The carton box was explicitly modeled, and the grape bunches inside the carry bags was treated as a porous media. The plastic liner was modeled as porous jump. The porous media and porous jump loss coefficients were determined using separate wind tunnel experiments, respectively. The presence of plastic liner increased the cooling time of grapes significantly, and the lowest moisture loss occurred in fruits packed inside a nonperforated plastic liner. However, packaging with a non-perforated plastic liner resulted in the highest in-package condensate. The airflow and the heat transfer characteristics were also highly influenced by the orientation and stacking pattern of packages. Forcing the cooling air through the package side-walls with the highest vent area resulted in better air penetration and increased produce cooling rate in the stack.