1/U Vs . 1/v0.8
1/v0.8 Vs . U
V0.8 Vs . U
1/U Vs . 1/V
✅ The correct answer is option A.
Heat Transfer MCQs
272. Open pan evaporators are preferred to be used, when the solution to be concentrated is
Scaling
Highly viscous
Corrosive
Salty
✅ The correct answer is option B.
273. For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is
Nu = 0.023 Re0.8 . Pr0.4
Nu = Gz
Nu = Gz
Nu = 2Gz0.5
✅ The correct answer is option C.
274. In pipe flow, heat is transferred from hot wall to the liquid by
Conduction only
Forced convection only
Forced convection and conduction
Free and forced convection
✅ The correct answer is option C.
275. Baffle spacing
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.
276. 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.
277. Viscosity of gases __________ with increase in temperature.
Increase very rapidly
Increase slowly
Decrease slowly
Remain unaffected
✅ The correct answer is option B.
278. 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.
279. 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.
280. Radiation heat losses from satisfactorily insulated high pressure boilar may be about __________ percent.
1
7
18
26
✅ The correct answer is option B.