Question: Choose the correct equation.
[A].Nu = (Re) (Pr) (Gz)
Nu = (Re) (Pr) (St)
Nu = (Re)(Pr)
Nu = (Pr)(St)
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
No answer description available for this question.
Heat Transfer
Dietus-Boelter equation used for the determination of heat transfer co-efficient is valid
Question: Dietus-Boelter equation used for the determination of heat transfer co-efficient is valid
[A].for fluids in laminar flow.
for fluids in tubulent flow.
when Grashhoff number is very important.
for liquid metals.
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
No answer description available for this question.
For what value of Prandtl number, St = f/2?
Question: For what value of Prandtl number, St = f/2?
[A].1.5
1
> 1
< 1
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
No answer description available for this question.
In forced convection, the heat transfer depends on
Question: In forced convection, the heat transfer depends on
[A].Re, Pr
Re, Gr
mainly Gr
Re only
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.
Natural convection is characterised by
Question: Natural convection is characterised by
[A].Grashhoff number
Peclet number
Reynolds number
Prandtl number
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.
Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is
Question: Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is
[A].0.1
>1
< 1
l
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.
At Pr > 1, conduction in an ordinary fluid flowing through a heated pipe is limited to the
Question: At Pr > 1, conduction in an ordinary fluid flowing through a heated pipe is limited to the
[A].buffer zone
turbulent core
both (a) and (b)
viscous sub-layer
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
No answer description available for this question.
Heat transfer co-efficient (h1) for liquids increases with
Question: Heat transfer co-efficient (h1) for liquids increases with
[A].increasing temperature.
decreasing temperature.
decreasing Reynolds number.
none of these.
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.
Fouling factor
Question: Fouling factor
[A].is a dimensionless quantity.
does not provide a safety factor for design.
accounts for additional resistances to heat flow.
none of these.
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
No answer description available for this question.
Nusselt number is the ratio of the
Question: Nusselt number is the ratio of the
[A].temperature gradient of the wall to that across the entire pipe.
temperature difference to the temperature gradient at the wall.
heat flux at the wall to that across the entire pipe.
none of these
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
No answer description available for this question.