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
Discussion:
12 comments Page 1 of 2.
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.
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.
In forced convection h is function of Pr number and Re number.
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.
Prandtl number, Grashoff's number. In forced convection h is function of Pr number and Re number.
Sai krishna said:
1 decade ago
Would you please explain me Reynold's number, Grashof's number and Prandtl number?
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.
Re = VD/v or (rho*V*D)/mu.
Prandtl number = hl/k.
Grashoff's number = (rho*g*B*l2*dt3)/mu.
Ayyappa said:
10 years ago
In free convection Reynold's number matters. It is simply function of Grashoff's and prandtl.
Amulraj said:
9 years ago
Refer heat and mass transfer data book CP Kothandraman. It contains all the formulas and relations.
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.
Nusselt number is a function of GR No and PR No.
So the answer should be B.
(1)
Sreerag said:
8 years ago
@Rohit.
I think Prandtl no = meu. Cp/k.
I think Prandtl no = meu. Cp/k.
(1)
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)
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