Gives a higher shell side pressure drop
Gives a lower shell side pressure drop
Can pack more surface area into a shell of given diameter
None of these
✅ The correct answer is option A.
Heat Transfer MCQs
For an ideal black body
Absorptivity = 1
Reflectivity = 1
Emissivity = 0
Transmissivity = 1
✅ The correct answer is option A.
The driving potential for the crystal growth during crystallisation is the __________ of the solution.
Concentration
Viscosity
Super-saturation
Density
✅ The correct answer is option C.
Calburn analogy is applicable for the value of Prandtl number from
0.001 to 1
0.6 to 120
0.5 to 5
120 to 400
✅ The correct answer is option B.
A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m².°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be
Greater than that for uninsulated steam pipe
Less than that of the uninsulated steam pipe
Equal to that of the uninsulated steam pipe
Less than the steam pipe with 5 cms insulation
✅ The correct answer is option B.
Prandtl number is the ratio of
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.
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.
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.
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.
A __________ evaporator employs an annular downtake.
Basket type
Horizontal
Long tube vertical
None of these
✅ The correct answer is option A.