Related Questions

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
Which of the following forced convection heat transfer equation accounts for the liquid viscosity effect for viscous liquids?
A Dittus-Boeltier equation
B Sieder-Tate equation
C Nusselt equation
D None of these
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
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
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
The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as
A $${\left( {\Delta {\text{T}}} \right)^{\frac{1}{4}}}$$
B $${\left( {\Delta {\text{T}}} \right)^{\frac{1}{2}}}$$
C $${\left( {\Delta {\text{T}}} \right)^{\frac{5}{4}}}$$
D $${\left( {\Delta {\text{T}}} \right)^{\frac{3}{4}}}$$
Which of the following is unimportant in forced convection?
A Reynolds number
B Prandtl number
C Grashhoff number
D None of these
In forced convection, the Nusselt number is a function of
A Re and Pr
B Re and Gr
C Pr and Gr
D Re and Sc
Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator?
A Long vertical evaporator
B Horizontal tube evaporator
C Agitated film evaporator
D Calenderia vertical tube evaporator
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
A Increases
B Decreases
C Remains constant
D Passes through a maxima

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