Related Questions

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is __________ compared to the same size pipes without fins.
A More
B Less
C Same
D Unpredictable
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
If a heat transfer surface is pock-marked with a number of cavities, then as compared to a smooth surface the heat transfer by __________ will not increase.
A Convection
B Nucleate boiling
C Radiation
D Conduction
In which of the following cases provision of fins on a given heat transfer surface will be more effective?
A Fewer but thin fins
B Large number of thin fins
C Large number of thick fins
D Fewer but thick fins
Even though heat transfer co-efficients in boiling liquids is large, use of fins is advantageous, when the entire surface is exposed to __________ boiling.
A Film
B Nucleate
C Transition
D All of the above
In spite of large heat transfer co-efficients in boiling liquids, fins are used advantageously, where the entire surface is exposed to __________ boiling.
A Film
B Nucleate
C Transition
D All of the above
In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate.
A Increases
B Decreases
C Does not affect
D May increase or decrease, depends on the type of baffle
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
A Increases
B Decreases
C Remains constant
D Passes through a maxima
With increase in the distance between the heat source and the object receiving the heat, the radiation heat transfer
A Decreases
B Increases
C Increases exponentially
D Remains unaffected

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