Air flow effects on heat and mass transfer during cooling of chicory roots

Abstract

This paper presents a transient CFD model of heat and mass transfer in porous bulks of chicoryroots. The model consists of the full system of conservation equations of momentum, energy andmass for the two-phase air-product matrix through bulk of chicory roots. A finite volume code(CFX, Harwell, UK) is used to solve the model equations, which is then validated againstexperimental data. The results show a good agreement between the model and the experiments.Differences between predicted and measured weight loss only amount to maximum 0.3% afterthe initial cooling period. The non-ideal experimental conditions, the various sizes of theproducts and the small scale of the porous region compared to the size of the product contributeto the observed differences between experiment and simulation, but do represent reality.Humidity and air velocity have a strong effect on the cooling rate and the weight-loss of theproduct. The results led to an improved understanding of the cooling process with differentairflow conditions. The model can be applied to study the cooling process in an industrial coldstore to find the optimal process settings to improve the product quality and reduce productweight.