The Cooper Cooler is a novel cooling device that rotates a cylindrical beverage can within a chilled environment in order to cool down the beverage. In a related process shown in the figure, the correlation for convective heat transfer associated with the liquid film on the inside surfaces of a rotating can is given by

where N is the rotation rate (rev/sec) and D_r is the diameter of the rotating wheel. In the present process, the chilling chamber is kept constant at 0°C. The convective heat-transfer coefficient on the outside surface of the can is estimated at 1000 W/m² · K, and the heat-transfer resistance through the metal can is considered negligible. If the can is 6 cm in diameter, 10 cm long, and D_r/2 is 12 cm, how long will it take to cool the contents of the can down to a refreshing 4°C if the beverage can is initially at 20°C and the wheel is rotated at 0.5 rev/s? It is assumed that the thermo physical properties of water apply for the beverage.

Transcribed Image Text:

DNp 2.9 Re0.436Pr0.287 with Re Nu = rotating cans / D,/ 2