Theoretically Analyze the cool down of a standard ceramic coffee cup left out on
ID: 1020732 • Letter: T
Question
Theoretically Analyze the cool down of a standard ceramic coffee cup left out on an open desk and find the heat rates of the following:
A)Natural convection off the sides and top of the liquid surface
B)Radiation heat transfer from the sides and top of the cup
C)Conduction through the liquid to the air surrounding the cup
D) Conduction heat rates through the cup into the surface below
E) Evaluate the evaporation cooling rate assuming a stagnant mass of extremely dry air above the cup, be prepared to answer and model how this calculation varies with some relative humidity present in the air above the cup?
Explanation / Answer
Most of the ceramics have low thermal conductivity at room temperature.
The heat transfer from the coffee to the air is by convection. Most of the ceramics at room temperatures are insulating and possess low thermal conductivities.
The coffee cools down due to radiation between the surface of the tea and the air molecules.
Further conduction between the tea and the cup itself and between the cup and the table or whatever the surface is.
Natural convection off the sides will be minimum and top of the liquid surface will be maximum.
Radiation heat transfer from the sides will be minimum and top of the cup will be maximum
Conduction through the liquid to the air surrounding the cup will contribute to cooling in a large extent.
Conduction of heat through the cup into the surface below will try to establish equilibrium in the temperature of the coffee.
Relative humidity present in the air above the cup lowers the transfer of heat in the surrounding.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.