PRECOOLING of CYLINDRICALLY SHAPED GRAPES: EXPERIMENTAL and THEORETICAL HEAT TRANSFER RATES

Transient heat transfer during the forced-air precooling of cylindrically shaped grapes in a batch of 5 kg was investigated both experimentally and theoretically. Experiments were conducted to measure center temperatures of the cylindrical grapes in air at 4C, and flow velocities of 1, 1.25, 1.5, 1.75, and 2 m/s. From the experimental temperature data, the dimensionless measured heat transfer rates were determined. Considering both convection and radiation, the dimensionless theoretical heat transfer rates were predicted. Good agreement was shown to exist between the predicted and experimental results. Therefore, the simple and accurate method of this study is applicable to the estimation of heat transfer rates.