Related Questions

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
Dropwise condensation is promoted on a/an __________ surface.
A Glazed
B Oily
C Coated
D Smooth
The most conducive surface for dropwise condensation to occur is the __________ surface.
A Coated
B Oily
C Glazed & polished
D Smooth
Dropwise condensation occurs on __________ surfaces.
A Clean and dirt free
B Smooth clean
C Contaminated cooling
D Polished
Dropwise condensation of steam on cooling surface is promoted
A An oily surface
B When both the steam and the tube are clean
C Only in presence of air
D None of these
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
Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer.
A No
B The least
C The largest
D Lower
The film thickness for laminar film condensation on vertical surface __________ from top to bottom.
A Cummulatively increases
B Cummulatively decreases
C Remains constant
D And the surface conductance increase
Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling.
A CO2
B SO2
C NH3
D None of these

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