Is not the same as baffle pitch
Should be less than one fifth the diameter of the shell
Should be less than the inside diameter of the shell
None of these
✅ The correct answer is option C.
Heat Transfer MCQs
In Biot number, the characteristic length used is the ratio of the __________ of the solid.
Volume to surface area
Perimeter to surface area
Surface area to volume
Surface area to perimeter
✅ The correct answer is option A.
Viscosity of gases __________ with increase in temperature.
Increase very rapidly
Increase slowly
Decrease slowly
Remain unaffected
✅ The correct answer is option B.
The critical radius of insulation for a spherical shell is (where, K = thermal conductivity of insulating material h0 = heat transfer coefficient at the outer surface)
K/h0
2K/h0
h0/K
h0/2K
✅ The correct answer is option B.
The purpose of providing bleed points in the evaporator is to
Admit the feed
Remove the product
Facilitate removal of non-condensable gases
Create vacuum
✅ The correct answer is option C.
Radiation heat losses from satisfactorily insulated high pressure boilar may be about __________ percent.
1
7
18
26
✅ The correct answer is option B.
Air is best heated with steam in a heat exchanger of
Plate type
Double pipe type with fin on steam side
Double pipe type with fin on air side
Shell and tube type
✅ The correct answer is option C.
The main purpose of providing fins on heat transfer surface is to increase the
Temperature gradient
Mechanical strength of the equipment
Heat transfer area
Heat transfer co-efficient
✅ The correct answer is option C.
Peclet number (Pe) is given by
Pe = Re.Pr
Pe = Re/Pr
Pe = Pr/Re
Pe = Nu.Re
✅ The correct answer is option A.
A body cools down from 75°C to 70°C in 10 minutes. It will cool down from 70° C to 65° C in __________ minutes.
10
>10
<10
Either B or C, depends on the mass of the body
✅ The correct answer is option B.