Thermodynamics HW Solutions 371

Thermodynamics HW Solutions 371 - Chapter 4 Transient Heat...

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Chapter 4 Transient Heat Conduction 4-102E Chickens are to be frozen by refrigerated air. The cooling time of the chicken is to be determined for the cases of cooling air being at –40°F and -80°F. Assumptions 1 Steady operating conditions exist. 2 The thermal properties of chickens are constant. Analysis The time required to reduce the inner surface temperature of the chickens from 32ºF to 25ºF with refrigerated air at -40ºF is determined from Fig. 4-44 to be t 2.3 hours Air -40 ° C Chicken 6 lbm 32 ° F If the air temperature were -80ºF, the freezing time would be t 1.4 hours Therefore, the time required to cool the chickens to 25 ° F is reduced considerably when the refrigerated air temperature is decreased. 4-103 Chickens are to be cooled by chilled water in an immersion chiller. The rate of heat removal from the chicken and the mass flow rate of water are to be determined. Assumptions 1 Steady operating conditions exist. 2 The thermal properties of chickens are constant.
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This note was uploaded on 01/19/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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