Oranges of 2.5-in-diameter (k=0.26 Btu/hftF and alpha=1.4×10^(-6) ft^2/s) initially at a uniform temperature of 78 F are to be cooled by refrigerated air at 25 F flowing at a velocity of 1 ft/s. The average heat transfer coefficient between the oranges and the air is experimentally determined to be 4.6 Btu/hft^2F. Determine how long it will take for the center temperature of the oranges to drop to 40 F. Also, determine if any part of the oranges will freeze during this process.
Oranges of 2.5-in-diameter (k=0.26 Btu/hftF and alpha=1.4×10^(-6) ft^2/s) initially at a uniform temperature of 78 F are to be cooled by refrigerated air at 25 F flowing at a velocity of 1 ft/s. The average heat transfer coefficient between the oranges and the air is experimentally determined to be 4.6 Btu/hft^2F. Determine how long it will take for the center temperature of the oranges to drop to 40 F. Also, determine if any part of the oranges will freeze during this process.