PhD Defense by Dihia Aguenihanai the 09th of April 2025

Jury :

Directed by :  Jean MOUREH, INRAE Frise and supervised by Steven DURET, INRAE FRISE, Denis FLICK, AgroParisTech and Fanny TENNENHAUS, Cniel

Abstract : Some food products continue to have a biological activity after their fabrication and thus during the entire transport and storage process. For example, cheeses in which the presence of ferments induces a respiratory activity associated with a significant generation of heat. The control of the temperature of these products throughout the cold chain remains a major industrial challenge in order to preserve all their gustative and sanitary qualities. The scientific approach will be based on the implementation of numerical and experimental tools to characterize and predict temperature changes and their heterogeneities within a range of cheese products. This according to the main parameters that drive the flows and transfers including, in particular, the packaging vents, heat fluxes generated by the cheese and the external ventilation level. The effect of natural convection within the pallet and the effects of adjacent pallets on the airflow around the pallets will also be considered. The experiments will be carried out in a test cell, at controlled temperature and air speed, on a model representing a pallet of cheese products that generate heat. A laser anemometer (LDV) will be used to measure the air velocities within the pallet. In the numerical part, two modelling approaches will be developed in a non-stationary regime; a CFD model with the ANSYS-Fluent code and a simplified model based on a zonal approach for industrial use with MATLAB. The validation of these models will be performed by comparison with experimental data on product cooling and heating kinetics within the pallet. After this validation, the final objective of the numerical models is to predict the evolutions of temperature and their dispersions within a pallet on the entire supply chain by taking into account the operating conditions in terms of air velocity and temperature of each link.