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.Management Sciences
Category: Chemical Heat Transfer
Mechanical recompression evaporation is used in the production of____________________?
0
A. Alcohol
B. Distilled water
C. Salt
D. Fruits jam
For an ideal black body______________________?
A. Absorptivity = 1
B. Reflectivity = 1
C. Emissivity = 0
D. Transmissivity = 1
Water is normally used as a coolant in the heat exchange equipments mainly because of its___________________?
A. Abundance & high heat capacity
B. Low density
C. Low viscosity
D. High fluidity
The separation of liquid droplets from the vapor is done by a/an _____________ in the evaporators?
A. Steam ejector
B. Entrainment separator
C. Compressor
D. Vacuum pump
In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred_________________?
A. Through a metallic wall
B. By direct contact of hot flue gas with air
C. By heating an intermediate material (like chequor bricks) and then heating the air from this
hot material
D. None of these
The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is _____________________?
A. 1200 W/m2.K
B. 894 W/m2.K
C. 333 W/m2.K
D. 287 W/m2.K
With increase in temperature, the thermal conductivity of steel___________________?
A. Increases
B. Decreases
C. Remains unchanged
D. Increases exponentially
In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will___________________?
A. Increase
B. Decrease
C. Remain unchanged
D. Either increase or decrease; depends on the coolant flow rate
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