MEEN 464 - True/False Questions and Correct Answers

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MEEN 464 - True/False Questions and
Correct Answers

Consider heat transfer between two identical hot solid bodies and their
environments. The first solid is dropped in a large container filled with water,
while the second one is allowed to cool naturally in the air. The lumped system
analysis is more likely to be applicable for the solid that is dropped in water
container.
Ans✅✅: False


Any objects made of plastic with low thermal conductivity can never be
considered as a lumped capacitance system.
Ans✅✅: False


In parallel-flow heat exchangers, the outlet temperature of the cold fluid may
exceed the outlet temperature of the hot fluid.
Ans✅✅: False


In counter-flow heat exchangers, the outlet temperature of the cold fluid may
exceed the outlet temperature of the hot fluid.
Ans✅✅: True


The fouling on the heat exchanger surfaces causes additional thermal
resistance, thus decreases the heat transfer rate.
Ans✅✅: True


The heat exchanger in problem 1 is a parallel-flow concentric tube heat
exchanger. Hint: note the temperature changes of cold and hot fluids
Ans✅✅: False

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