Solution has an elevation of boiling point
Evaporators operate under vacuum
Evaporators opreate at atmospheric pressure
None of these
✅ The correct answer is option A.
Heat Transfer MCQs
372. When warm and cold liquids are mixed, the heat transfer is mainly by
Conduction
Convection
Radiation
Both A & C
✅ The correct answer is option B.
373. In natural convection heat transfer, the correlating parameter is the
Graetz number
Eckert number
Grashoff number
Bond number
✅ The correct answer is option C.
374. Heat exchangers operating, when the asymptotic range is reached,
Provide very large heat transfer co-efficient
Results in making part of the heating surface inactive
Results in abruptly increased velocity
None of these
✅ The correct answer is option B.
375. In a forward feed multiple effect evaporator, the pressure is
Highest in last effect
Lowest in last effect
Same in all effects
Dependent on the number of effects
✅ The correct answer is option B.
376. Steam side heat transfer co-efficient in an evaporator is in the range of __________ kcal/hr.m²°C.
Oct-50
100-500
1000-1500
5000-15000
✅ The correct answer is option D.
377. Nusselt number for full developed, laminar, constant property flow in a pipe at uniform heat flux is
0.72
4.364
18
83
✅ The correct answer is option B.
378. A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides
Higher economy
Lower capacity
Both A & B
Lower economy
✅ The correct answer is option A.
379. In forced circulation, the heating element is injected
Internally
Externally
Both A and B
Neither A nor B
✅ The correct answer is option A.
380. The unit of conductance in SI unit is
W/m
W/m²
W/°K
W/m°K
✅ The correct answer is option C.