7. Cooling a Pot of Soup in Air Available to Purchase

In this chapter, the temperature-time history of a hot pot of soup which is immersed in still-air environment will be analyzed as shown in Figure 7-1. The still-air environment’s temperature is controlled and it varies linearly with time. The hot soup in the thin-walled aluminum pot will have negligible internal conduction heat transfer resistance as compared to the external free convection heat transfer resistance to the still-air environment, namely the body of the hot soup will almost have a constant temperature during the cooling process. Free convection heat transfer coefficient between the still-air environment is assumed to be a constant during the whole cooling process and all air properties are calculated at film temperature.