Analysis of heterogeneous cooling of agricultural products inside bins Part I: Aerodynamic study

An experimental aerodynamic study was carried out in order to obtain a bett er understanding of the heterogeneous treatment observed during the forced convection cooling of products conditioned in bins. Velocity and turbulence intensity were measured at different depths inside a bin of spherical prod ucts. Airflow was far from being a plug flow: the air was introduced at the centre of the inlet wall and progressively redistributed over the width of the bin, generating two lateral back-mixings. From the fourth row of spher es onwards, the air flowed preferentially in the empty space between the bi n in question and the one above, i.e. above the products, and between the p roducts and the bin walls. The turbulence generated behind the products inc reased turbulence intensity by up to 60%, The study gives a clearer explana tion (detailed in Part II) of the heat transfer phenomena observed experime ntally. Changes in bin geometry are recommended to improve airflow around t he products. (C) 1999 Elsevier Science Ltd. All rights reserved.