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.Management Sciences
Category: Chemical Heat Transfer
Convective heat transfer co-efficient in case of fluid flowing in tubes is not affected by the tube length/diameter ratio, if the flow is in the _____________ zone?
0
A. Laminar
B. Transition
C. Both A & B
D. Highly turbulent
Reason for operating an evaporator in multiple effects is to secure ___________________?
A. Increased steam economy
B. Decreased steam consumption
C. Both A. and B.
D. Increased capacity
Log mean temperature difference (LMTD) cannot be used, if ___________________?
A. Heat transfer co-efficient over the entire heat exchanger is not constant
B. There exists an unsteady state
C. The heat capacity is not constant and there is a phase change
D. None of these
Heat sensitive materials can be concentrated in an evaporator employing_______________?
A. Vacuum
B. High pressure
C. High residence time
D. None of these
The ratio of momentum diffusivity to thermal diffusivity is the ______________ number?
A. Prandtl
B. Nusselt
C. Stanton
D. Grashoff
Viscosity of gases ______________ with increase in temperature?
A. Increase very rapidly
B. Increase slowly
C. Decrease slowly
D. Remain unaffected
Sensible heat absorbed by 1 lb of water when it is heated from 32 to 212°F may be around ______________ BTU?
A. 180
B. 970
C. 3.97
D. Data insufficient, can’t be predicted
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