Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion

Discussion Forum : Heat Transfer, Refrigeration and Air Conditioning - Section 1 (Q.No. 4)
4.
In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
Reynold's number
Grashoff's number
Reynold's number, Grashoff's number
Prandtl number, Grashoff's number
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
12 comments Page 1 of 2.

Sudheer said:   1 decade ago
In free convection the two dimensionless numbers are Grashof's number & Prandtl numberwhere it is replaced by Reynold's number & Prandtl number for forced convection. In free convection h is function of Pr number and Gr number.

Prandtl number, Grashoff's number. In forced convection h is function of Pr number and Re number.

Sai rama prabhakar said:   1 decade ago
In free convection the two dimensionless numbers are grashof's number & prandtl number where it is replaced by reynold's number & prandtl number for forced convection.

Jonty said:   7 years ago
In free convection Nusselt number is a function of Re and Gr, on the other hand it is a function of Re and Pr for forced convection. So, answer C is correct.
(1)

Rohit said:   10 years ago
Reynolds number = Re = Inertia forces/Viscous forces.

Re = VD/v or (rho*V*D)/mu.

Prandtl number = hl/k.

Grashoff's number = (rho*g*B*l2*dt3)/mu.

Rakesh said:   2 years ago
In free convection heat transfer, the transition from Laminar to turbulent flow is governed by the Prandtl number and Grashoff's number.
(2)

Gaurav said:   8 years ago
Critical value in free convection is Grashoff number only.
Nusselt number is a function of GR No and PR No.
So the answer should be B.
(1)

Sanju said:   1 decade ago
In free convection h is function of Pr number and Gr number.

In forced convection h is function of Pr number and Re number.

Amulraj said:   9 years ago
Refer heat and mass transfer data book CP Kothandraman. It contains all the formulas and relations.

Ayyappa said:   10 years ago
In free convection Reynold's number matters. It is simply function of Grashoff's and prandtl.

Sai krishna said:   1 decade ago
Would you please explain me Reynold's number, Grashof's number and Prandtl number?


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