481. In a shell and tube heat exchanger, the shell side fluid velocity can not be changed by changing the
Tube layout
Tube diameter
Tube pitch
No. of baffles
✅ The correct answer is option B.
Heat Transfer MCQs
482. Indirect contact heat exchangers are preferred over direct contact heat exchangers, because
Heat transfer co-efficient are high
There is no risk of contamination
There is no mist formation
Cost of equipment is lower
✅ The correct answer is option B.
483. In a forward feed multiple effect, the pressure build up will be
Least at the inlet of the first effect
Least at the outlet of the last effect
Highest at the inlet of the last effect
Highest at the outlet of the last effect
✅ The correct answer is option B.
484. It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is
3.06 x l0⁵
6.12 x 10⁵
7.24 x 10⁵
9.08 x 10⁵
✅ The correct answer is option A.
485. Multiple effect evaporators are commonly used in the manufacture of P. Paper Q. Superphosphate R. Sugar S. Fats
P and Q
P and R
P and S
R and S
✅ The correct answer is option C.
486. Overall thermal resistance for conductive heat transfer through a series of flat resistances is equal to the
Maximum resistance in the series
Sum of all resistances
Average of all resistances
Minimum resistance presents in the series
✅ The correct answer is option B.
487. The purpose of providing expansion bellows in the shell of tubular exchanger is to
Increase the heating load
Impart structural strength
Account for the uneven expansion of shell and tube bundles
Facilitate increase of shell length, if needed
✅ The correct answer is option C.
488. 200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 x 10⁻³ kg/m².s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m²/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)
0.5
0.05
0.1
0.15
✅ The correct answer is option C.
489. A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of materialA is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is __________ °C.
6
12
18
24
✅ The correct answer is option B.
490. Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger?
Tube side pressure drop and the heat transfer rate
Convective heat transfer co-efficient
Effective tube surface area for convective heat transfer
All of the above
✅ The correct answer is option D.