A hybrid numerical approach for characterising airflow and temperature distribution in a ventilated pallet of heat-generating products: Application to cheese

Temperature control throughout the cold chain is of crucial importance in the preservation of the quality of cheese. As a result of cheese heat generation, both natural and forced convection need to be considered. This numerical study aimed to characterise the airflow and temperature fields within a ventilated pallet of heat-generating cheeses. An original computational fluid dynamics (CFD) hybrid approach was developed. This approach is based on a combination of a porous media approach for the contents of the boxes and a direct CFD approach for the outer cardboard walls, including vent size and position. The computational domain is limited to one pallet level. The simulations were conducted on a steady state for two upwind air velocities 0.31 m/s and 0.73 m/s and three generated heat fluxes 0.05 W, 0.15 W, and 0.3 W per product item (250 g). The model was validated by comparison with experimental results related to velocity and product temperature profiles obtained on a full-scale experimental set-up. The hybrid approach shows good accuracy while reducing the mesh size and the computational time in comparison with the direct CFD approach.