Chemical Engineering - Heat Transfer

1. 

Intermittant tube cleaning is possible to be done in case of a __________ evaporator.

A. basket type
B. horizontal tube
C. calendria
D. none of these

Answer: Option A

Explanation:

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2. 

Harmonic mean temperature difference is given by

A. ΔT1 . ΔT2
B.
C.
D.

Answer: Option B

Explanation:

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3. 

Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is

A. thin walled having the value of Ao Ai/< 2.
B. thick walled.
C. having the value of Ao/Ai > 2.
D. both (b) and (c).

Answer: Option A

Explanation:

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4. 

Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for

A. cube
B. cylinder
C. sphere
D. equal for all the three

Answer: Option A

Explanation:

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5. 

Overall heat transfer co-efficient for cooling of hydrocarbons by water is about

A. 50 -100 Kcal/hr.m2.°C
B. 50 -100 W/m2 . °K
C. 50 -100 BTU/hr. ft.2°F
D. 1000 - 1500 BTU/hr. ft.2°F

Answer: Option C

Explanation:

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