Analysis of heterogeneous cooling of agricultural products inside bins Part II: Thermal study

An experimental thermal study was performed in order to characterise heat t ransfer intensity for spherical objects packed in stacked bins and cooled b y air forced convection. The heat transfer coefficient was measured for eac h sphere in a test bin using spherical sensors. Large differences in heat t ransfer coefficient values, up to 40%, were observed. This heterogeneity co uld be explained by the fact that the airflow is not uniform (cf. Part I). Each object was exposed to local airflow conditions (mean velocity and turb ulence). A correlation was established between the local heat transfer coef ficients and local airflow parameters. Cylindrical sensors were also constr ucted in order to measure the heat transfer coefficient inside packed spher es. The measurements correlated well with the spherical sensors for the sam e positions in the bins. (C) 1999 Elsevier Science Ltd. Ail rights reserved .