Heat transfer co-efficient
Thermal diffusivity
Thermal conductivity
Stefan-Boltzman constant
✅ The correct answer is option C.
Engineering MCQs
Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube
Exit-fluid temperature > wall temperature
Exit fluid temperature < wall temperature
Exit fluid temperature = wall temperature
Graetz number > 100
✅ The correct answer is option C.
Which of the following has maximum thermal conductivity at the same temperature?
Steel
Petrol
Air
All of the above
✅ The correct answer is option A.
An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is
4000
9000
4600
3000
✅ The correct answer is option A.
The thermal radiation emitted by a body is proportional to Tn, where T is its absolute temperature. The value of ‘n’ is exactly 4 for
Black painted bodies only
All bodies
Polished bodies only
A black body
✅ The correct answer is option B.
For a multipass shell and tube heat exchanger, the LMTD correction factor is always
1
> 1
< 1
Between 1 & 2
✅ The correct answer is option C.
Choose the correct equation.
Nu = (Re) (Pr) (Gz)
Nu = (Re) (Pr) (St)
Nu = (Re)(Pr)
Nu = (Pr)(St)
✅ The correct answer is option B.
Radiant energy received by a body is proportional to (where, d = the distance between the object emitting radiation and that receiving it.)
√d
d
d2
d1.5
✅ The correct answer is option C.
In a single effect evaporator, the economy is
1
< 1
> 1
None of these
✅ The correct answer is option B.
As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient
Continues to increase
Continues to decrease
Goes through a minimum
Goes through a maximum
✅ The correct answer is option C.