Experimental measurement and numerical modelling of cooling rates of bulk-packed chicken drumsticks during forced-air freezing

Abstract

• Experimental freezing trials of packed chicken drumsticks were performed. • A numerical model for the freezing drumsticks was developed and validated. • Drumstick packing arrangement did not have a significant effect on freezing rate. • The presence of a liner bag increased freezing time by more than a factor of three. The cooling of polylined bulk-packed drumsticks during forced-air freezing was examined experimentally and numerically. The experiments showed that, when contained within the liner bag, the packing arrangement of the chicken drumsticks within the tray did not have a significant impact on freezing rate. However, the presence of the liner bag had a significant impact on freezing times, increasing them by more than a factor of three. A 3D computational fluid dynamics (CFD) model to predict the temperature profile of bulk-packed drumsticks, based on 3D computed tomography images of the chicken, was also developed and validated against the experimental cooling data. By using temperature-dependent thermal properties of chicken meat, the mean differences between the predicted average drumstick temperatures and corresponding experimental results were less than 1.1°C for all tested conditions. Based on the validated model, a correlation was proposed to estimate the effect of operating conditions on freezing time and that correlation may be used to optimise the design of the freezing tunnel for chicken products.