A multiphysics approach for modeling gas exchange in microperforated films for modified atmosphere packaging of respiring products

The objective of this work is to quantify, model and verify how the interactions between the respiring products and the surrounding atmosphere in a package affect the gas exchange through a microperforation. The pressure drop generated in a closed system by the metabolic activity of five different products has been determined by direct and indirect measurements. In this way, the estimated compensating hydrodynamic flows that can pass through the microperforated film ranged from 0.34 to 4.75 mL h-1. A 3D model that considers the mass transfer coupled with the momentum transfer has been proposed to predict the gas concentration profiles around the microperforations originated by the diffusive and convective flows. A novel gas exchange measurement system, able to deliver small convective airflows comparable to those obtained for the different products and conditions, was assembled for the model verification. The model correctly predicts experimental data obtained for different convective flows.