Momentum diffusivity to mass diffusivity
Momentum diffusivity to thermal diffusivity
Thermal diffusivity to mass diffusivity
Thermal diffusivity to momentum diffusivity
✅ The correct answer is option B.
Heat Transfer MCQs
82. A 2-4 heat exchanger involves
Only counter-flow of fluids
Only parallel-flow of fluids
Both counter and parallel-flow of the fluids
Smaller pressure drop compared to 1-2 exchanger
✅ The correct answer is option C.
83. Thickness of thermal boundary layer is more compared to that of hydrodynamic boundary layer, when the value of Prandtl number is
1
< 1
> 1
> 5
✅ The correct answer is option B.
84. The separation of liquid droplets from the vapor is done by a/an __________ , in the evaporators.
Steam ejector
Entrainment separator
Compressor
Vacuum pump
✅ The correct answer is option B.
85. A __________ evaporator employs an annular downtake.
Basket type
Horizontal
Long tube vertical
None of these
✅ The correct answer is option A.
86. Presence of a non-condensing gas in a condensing vapour
Increases the rate of condensation
Decreases thermal resistance
Is desirable to increase the film co-efficient
None of these
✅ The correct answer is option D.
87. Black liquor generated during paper manufacture is concentrated in a
Single effect evaporator
Single effect evaporator followed by a crystalliser
Multiple effect evaporator
Multiple effect evaporators followed by a crystalliser
✅ The correct answer is option C.
88. Absorptivity and refletivity of a perfect black body are respectively
1 and 0
0 and 1
1 and ?
0 and 0.5
✅ The correct answer is option A.
89. Baffles are provided in heat exchangers to increase the
Fouling factor
Heat transfer area
Heat transfer co-efficient
Heat transfer rate
✅ The correct answer is option C.
90. In a heat exchanger, one transfer unit means
A section of the exchanger in which change in temperature of one stream equals the average driving force in the section
The size of the exchanger in which heat transfer rate is 1 kcal/hr
Both A and B
None of these
✅ The correct answer is option A.