Chemical Engineering - Heat Transfer

16. 

Fouling factor

A. is a dimensionless quantity.
B. does not provide a safety factor for design.
C. accounts for additional resistances to heat flow.
D. none of these.

Answer: Option C

Explanation:

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17. 

In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient

A. increases
B. decreases
C. is not affected
D. may increase or decrease; depends on the feed

Answer: Option B

Explanation:

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18. 

The steam ejector is used to

A. remove condensate from the steam pipelines.
B. create vacuum.
C. superheat the steam.
D. none of these.

Answer: Option B

Explanation:

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19. 

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

Answer: Option D

Explanation:

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20. 

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are

A. (COP)R = (COP)HP = 0.6
B. (COP)R = 2.5; (COP)HP = 1.5
C. (COP)R = 1.5; (COP)HP = 2.5
D. (COP)R = (COP)HP = 2.5

Answer: Option C

Explanation:

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