Q) An apple has been put into a freezer at (-23°C) to be cooled. Initially,the apple is at a uniform temperature of 15°C. The convection heat transfercoefficient on its surface is 16 W/m2.°C. Assuming the apple as a spherehaving a diameter of 7-cm and taking its properties as p = 925 kg/m3, c, =1890 J/kg. C, and k =0.225 W/m:°C, determine; (a) the centertemperature of the apple in 40 minutes, (b) the actual anmount of heattransfer from the apple, and (c) the final equilibrium temperature of theapple.Hint: consider the temperature is a function of location and time.

Q) An apple has been put into a freezer at (-23°C) to be cooled. Initially, the apple is at a uniform temperature of 15°C. The convection heat transfer coefficient on its surface is 16 W/m2.°C. Assuming the apple as a sphere having a diameter of 7-cm and taking its properties as p = 925 kg/m³3, C - 1890 J/kg°C, and k (a) the center 0.225 W/m°C, determine; temperature of the apple in 40 minutes, (b) the actual amount of heat transfer from the apple, and (c) the final equilibrium temperature of the apple.

Q) An apple has been put into a freezer at (-23°C) to be cooled. Initially, the apple is at a uniform temperature of 15°C. The convection heat transfer coefficient on its surface is 16 W/m2.°C. Assuming the apple as a sphere having a diameter of 7-cm and taking its properties as p = 925 kg/m³3, C - 1890 J/kg°C, and k (a) the center 0.225 W/m°C, determine; temperature of the apple in 40 minutes, (b) the actual amount of heat transfer from the apple, and (c) the final equilibrium temperature of the apple.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.19P: 1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the...

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Concept explainers

Conduction and Convection

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a burner, heats up because of the flame underneath it.

Question

Q) An apple has been put into a freezer at (-23°C) to be cooled. Initially,
the apple is at a uniform temperature of 15°C. The convection heat transfer
coefficient on its surface is 16 W/m2.°C. Assuming the apple as a sphere
having a diameter of 7-cm and taking its properties as p = 925 kg/m3, c, =
1890 J/kg. C, and k =
0.225 W/m:°C, determine; (a) the center
temperature of the apple in 40 minutes, (b) the actual anmount of heat
transfer from the apple, and (c) the final equilibrium temperature of the
apple.
Hint: consider the temperature is a function of location and time.

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