Effect of pallet box stacking on cooling of horticultural products in cool stores.
Verboven, P., Hoang, M.L., Schenk, A. and Nicolaï, B.M.
ISHS Acta Horticulturae 556: 239-244.
2001
บทคัดย่อ
Precooling is applied to rapidly reduce the temperature of freshly harvested products before storage. For this purpose, small batches of pallet boxes are put into the cool store, which is consequently not completely filled. Depending on the configuration of the boxes, cooling occurs at different rates at different positions. This can lead to unacceptable losses of product quality and yield. A mathematical model, based on Computational Fluid Dynamics, has been used to calculate the distribution of air velocity and temperature in operational cool stores. This paper presents the model and computational results for the airflow and the temperature distribution in a cool store. The turbulent airflow has been modelled by means of Reynolds-averaged transport equations and the kappa - epsilon model. The convection-diffusion equation for energy is solved. In the pallet boxes, the air and product phases are distinguished on the macro-porous level. The airflow through the porous stack is modelled by means of an Ergun-type empirical equation relating pressure drop to the volume-averaged velocity in the boxes based on experimental data. A finite volume formulation of the model is solved using a commercial CFD code. The precooling of a batch of apples is investigated. A vertical stack of the boxes results in a better distribution of the airflow into the boxes, increases the cooling rate and reduces the temperature differences between different boxes.