Chapter 4 Transient Heat Conduction4-101 Turkeys are to be frozen by submerging them into brine at -29°C. The time it will take to reduce the temperature of turkey breast at a depth of 3.8 cm to -18°C and the amount of heat transfer per turkey are to be determined. Assumptions1 Steady operating conditions exist. 2 The thermal properties of turkeys are constant. Brine -29°C Turkey Ti= 1°C PropertiesIt is given that the specific heats of turkey are 2.98 and 1.65 kJ/kg.°C above and below the freezing point of -2.8°C, respectively, and the latent heat of fusion of turkey is 214 kJ/kg. Analysis The time required to freeze the turkeys from 1°C to -18ºC with brine at -29ºC can be determined directly from Fig. 4-45 to be t ≅180 min. ≅3 hours(a) Assuming the entire water content of turkey is frozen, the amount of heat that needs to be removed from the turkey as it is cooled from 1°C to -18°C is Cooling to -2.8ºC: kJ79.3C](-2.8)-C)[1kJ/kgkg)(2.987()(freshfreshcooling,=°°⋅=Δ=TCmQFreezing at -2.8ºC: kJ1498kJ/kg)kg)(2147(latentfreezing===hmQCooling -18ºC: kJ175.6C18)](2.8
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