To warm up some milk for a baby, a mother pours milk into a thin-walled cylindrical container whose diameter is 6 cm. The height of the milk in the container is 7 cm. She then places the container into a large pan filled with hot water at 70°C. The milk is stirred constantly so that its temperature is uniform at all times. If the heat transfer coefficient between the water and the container is 120 W/m 2 K, determine how long it will take for the milk to warm up from 3°C to 38°C. Assume the entire surface area of the cylindrical container (including the top and bottom) is in thermal contact with the hot water. Take the properties of the milk to be the same as those of water. Can the milk in this case be treated as a lumped system? Why?
To warm up some milk for a baby, a mother pours milk into a thin-walled cylindrical container whose diameter is 6 cm. The height of the milk in the container is 7 cm. She then places the container into a large pan filled with hot water at 70°C. The milk is stirred constantly so that its temperature is uniform at all times. If the heat transfer coefficient between the water and the container is 120 W/m 2 K, determine how long it will take for the milk to warm up from 3°C to 38°C. Assume the entire surface area of the cylindrical container (including the top and bottom) is in thermal contact with the hot water. Take the properties of the milk to be the same as those of water. Can the milk in this case be treated as a lumped system? Why?
Solution Summary: The author explains that milk can be treated as a lumped system, as the temperature of the milk is assumed to remain constant every time.
To warm up some milk for a baby, a mother pours milk into a thin-walled cylindrical container whose diameter is 6 cm. The height of the milk in the container is 7 cm. She then places the container into a large pan filled with hot water at 70°C. The milk is stirred constantly so that its temperature is uniform at all times. If the heat transfer coefficient between the water and the container is 120 W/m2 K, determine how long it will take for the milk to warm up from 3°C to 38°C. Assume the entire surface area of the cylindrical container (including the top and bottom) is in thermal contact with the hot water. Take the properties of the milk to be the same as those of water. Can the milk in this case be treated as a lumped system? Why?
A continuous flow calorimeter was used to obtain the calorific value of a sample of fuel and the following data collected:
Mass of fuel: 2.25 kgInlet water temperature: 11 ° COutlet water temperature 60 ° CQuantity of water: 360 Liters Calorimeter efficiency: 85%Calculate the calorific value of the sample ( kJ / kg ).
ive submitted this question twice and have gotten two way different answers. looking for some help thanks
15 kg of steel ball bearings at 100 ° C is immersed in 25 kg of water at 20 ° C . Assuming no loss of heat to or from the container, calculate the final temperature of the water after equilibrium has been attained.Specific heat of steel: 0.4857 kJ / kg / ° KSpecific heat of water: 4.187 kJ / kg / ° K
Sketch and explain a PV Diagram and a Temperature Entropy Diagram for a 4 stroke diesel engine
Chapter 4 Solutions
Heat and Mass Transfer: Fundamentals and Applications
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