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.Management Sciences
Category: Chemical Heat Transfer
Choose the most important factor on which the heat conducted through a wall in a unit time will depend on ?
A. Thickness of the wall
B. Area of the wall perpendicular to heat flow
C. Material of the wall
D. Temperature difference between the two surfaces of the wall
Vibrations in the tubes of a shell and tube heat exchanger is induced due to the _________________?
A. Flow of fluid on the tube and shell sides
B. Oscillations in the flow of shell/tube sides fluid
C. Vibrations transmitted through piping and/or supports due to external reasons
D. All A., B. and C.
Heat transfer occurs by natural convection because change in temperature causes difference in__________________?
A. Viscosity
B. Density
C. Thermal conductivity
D. Heat capacity
The actual temperature drop across the heating surface in an evaporator depends on the_________________?
A. Feed
B. Depth of liquid over heating surface
C. Pressure difference between steam chest and vapour space
D. All A., B. and C.
In a forward feed multiple effect, the pressure build up will be____________________?
A. Least at the inlet of the first effect
B. Least at the outlet of the last effect
C. Highest at the inlet of the last effect
D. Highest at the outlet of the last effect
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
For specified tube outside diameter, higher BWG means higher___________________?
A. Tube thickness
B. Cross-sectional area
C. Weight per unit length
D. None of these
The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the________________ ?
A. Solution has an elevation of boiling point
B. Evaporators operate under vacuum
C. Evaporators operate at atmospheric pressure
D. None of these
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