Related Questions

When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is
A Free convection
B Entry length problem in laminar forced conduction (developing thermal boundary layer)
C Mixed convection (both free and forced)
D Forced convection
In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
A Convection
B Radiation
C Conduction
D Both convection and conduction
Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
Critical value of the __________ number governs the transition from laminar to turbulent flow in free convection heat transfer.
A Grashoff
B Reynolds
C Both A & B
D Prandtl & Grashoff
In free convection heat transfer, Nusselt number is function of
A Grashoff number and Reynold number
B Grashoff number and Prandtl number
C Prandtl number and Reynold number
D Grashoff number, Prandtl number and Reynold number
Nusselt number is a function of Prandtl number and __________ number of fluid in natural convection heat transfer.
A Grashoff
B Biot
C Stantan
D Reynolds
In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
A Reynold's number
B Grashoff's number
C Reynold's number, Grashoff's number
D Prandtl number, Grashoff's number
Transition from laminar to turbulent zone in free convection heat transfer is governed by the critical value of
A Grashoff number
B Grashoff number & Reynolds number
C Reynolds number
D Grashoff number & Prandtl number
Nusselt number (for forced convection heat transfer) is a function of the __________ number.
A Prandtl
B Reynolds
C Both A & B
D Neither A nor B

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