Chemical Engineering - Heat Transfer

16. 

Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then

A. U1 = U2
B. U2 > U1
C. U1 > U2
D. U1 = dirt factor - U2

Answer: Option A

Explanation:

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17. 

In SI units, thermal conductivity is expressed in

A. Watt/m.°K
B. Watt/m2. °K
C. Watt/m2. °K
D. Watt/m4. °K

Answer: Option A

Explanation:

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18. 

Boiling point of a solution according to Duhring's rule is a linear function of the __________ of water.

A. boiling point (at the same pressure)
B. viscosity
C. density
D. thermal conductivity

Answer: Option A

Explanation:

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19. 

The overall resistance for heat transfer through a series of flat resistance, is the __________ of the resistances.

A. average
B. geometric mean
C. product
D. sum

Answer: Option D

Explanation:

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20. 

At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe ?

A. 0.5
B. < 0.5
C. > 0.6
D. < 0.1

Answer: Option C

Explanation:

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