Heat transfer co-efficient over the entire heat exchanger is not constant
There exists an unsteady state
The heat capacity is not constant and there is a phase change
None of these
✅ The correct answer is option D.
Engineering MCQs
In a shell and tube heat exchanger,
The temperature drops in the two fluids and the wall are proportional to individual resistances
The temperature drop is inversely proportional to the resistance across which the drop occurs
There is no relationship between temperature drop and resistance
The relationship is not generalised
✅ The correct answer is option A.
Steam is routed through the tube in case of a __________ evaporator.
Basket type
Horizontal tube
Short tube vertical
Long tube vertical
✅ The correct answer is option B.
In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.
Increases
Decreases
Remains constant
May increase or decrease, depends on the vacuum
✅ The correct answer is option A.
The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is
2.36
4.36
120.36
Dependent on NRe only
✅ The correct answer is option B.
A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is
6000
24000
60000
48000
✅ The correct answer is option B.
Steam trap is used to
Condense the steam flowing in the pipeline
Remove water resulting from partial condensation of steam
Stop the supply of steam
None of these
✅ The correct answer is option B.
In a backward feed multiple effect evaporator
Feed is introduced in the first effect
Feed flows from low pressure to high pressure
No pumps are required between successive effects
None of these
✅ The correct answer is option B.
The Grashoff number is defined as the ratio of the
Buoyancy to inertial forces
Buoyancy to viscous forces
Inertial to viscous forces
Buoyancy to surface tension forces
✅ The correct answer is option B.
Electromagnetic radiations propagate in vacuum with a velocity of __________ metre/second.
3 x l05
3 x l08
3 x l010
3 x l012
✅ The correct answer is option B.