11
'Fouling factor' used in the design of a multipass shell and tube heat exchanger is a
A)
Non-dimensional factor
B)
Factor of safety
C)
Conversion factor for individual film heat transfer co-efficient to overall heat transfer co-efficient
D)
None of these
Answer & Solution
Answer: Option
B
12
In a gas-liquid shell and tube heat exchanger, the
A)
Presence of a non-condensible gas decreases the condensing film co-efficient
B)
Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature
C)
Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain localised to the tubes
D)
All of the above
Answer & Solution
Answer: Option
D
13
In SI units, thermal conductivity is expressed in
A)
Watt/m.°K
B)
Watt/m2 .°K
C)
Watt/m3 .°K
D)
Watt/m4 .°K
Answer & Solution
Answer: Option
A
14
With increase in temperature, the thermal conductivity of most liquids
A)
Increases
B)
Decreases
C)
Remains same
D)
First increases upto a certain temperature and then becomes constant
Answer & Solution
Answer: Option
B
15
Which of the following has the lowest overall heat transfer co-efficient?
A)
Dowtherm
B)
Molten sodium
C)
Water
D)
Air
Answer & Solution
Answer: Option
D
16
Pick out the correct statement.
A)
1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F
B)
In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity
C)
In unsteady state heat conduction, heat flows in the direction of temperature rise
D)
In heat transfer by forced convection, Grashoff number is very important
Answer & Solution
Answer: Option
B
17
Value of Prandtl number for water ranges from
A)
1 to 2
B)
5 to 10
C)
100 to 500
D)
1000 to 2000
Answer & Solution
Answer: Option
B
18
1 BTU/hr.ft.°F is equal to __________ kcal/hr. m.°C.
A)
1.49
B)
1
C)
4.88
D)
None of these
Answer & Solution
Answer: Option
A
19
A process stream of dilute aqueous solution flowing at the rate of 10 Kg.s-1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s-1 . A 1 - 1 shell and tube heat exchanger is available. The best arrangement is
A)
Counter flow with process stream on shell side
B)
Counter flow with process stream on tube side
C)
Parallel flow with process stream on shell side
D)
Parallel flow with process stream on tube side
Answer & Solution
Answer: Option
A
20
Low thermal conductivity of heat insulating materials is due to its
A)
Dense structure
B)
High proportion of air space
C)
High specific heat
D)
None of these
Answer & Solution
Answer: Option
B
