Heat Analysis of Air Cooling of Strawberry ―Determination of Effective Heat Transfer Coefficient―

A finite element method (FEM) was applied to solve a heat transfer equation in the strawberry fruit, Toyonoka, assuming the modified heat transfer coefficient between strawberry fruit and cooling air at 0°C. We predicted the temperature distribution in a strawberry fruit cooled in an air flow and obtained the relationship between the modified heat transfer coefficient and the air velocity in the range of 0.1 m/s to 2.9 m/s. The results revealed that, 1) predicted temperature of strawberry fruit was closely matched with observed data. The cooling rate of strawberry fruit was the smallest near the center of the maximum radius section. It is the center point of strawberry during cooling operation, 2) the following empirical equation is used to calculate the modified heat transfer coefficient between strawberry fruit and cooling air at various air velocity from 0.1 m/s to 2.9 m/s: h=-3.97 v²+55.3 v+50.0.