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.Management Sciences
Category: Chemical Heat Transfer
Vent pipes are provided in a condenser to ________________?
A. Remove non-condensable gases
B. Purge the condenser
C. Facilitate easy cleaning of tubes
D. None of these
In a forward feed multiple effect evaporator unit__________________?
A. Viscosity of liquid is highest in first effect
B. Transfer from effect to effect is done by pumps
C. No pump is required to withdraw the product from the last effect
D. None of these
The ratio of kinematic viscosity to thermal diffusivity is called the _______________ number?
A. Peclet
B. Prandtl
C. Stanton
D. Nusselt
Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?
A. For fluids in laminar flow
B. For fluids in turbulent flow
C. When Grashoff number is very important
D. For liquid metals
Viscous & heat sensitive liquids are concentrated in _____________ evaporators?
A. Open pan
B. Long tube
C. Agitated film
D. None of these
Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?
A. Grashoff
B. Reynolds
C. Both ‘a’ & ‘b’
D. Prandtl & Grashoff
The rate of heat transfer through a pipe wall is given by, q = 2π k (Ti – T0)/ln (ri/r0). For cylinder of very thin wall, q can be approximated by__________________?
A. q = [2π k (Ti + T0)/2]/ln (ri/r0)
B. q = 2π ri k (Ti – T0)/(r0/ri)
C. q = 2π k (Ti – T0)/(r0/ri)
D. q = 2π k (Ti – T0)/[(r0 + ri)/2]
Economy of a multiple effect evaporator is not influenced much by the_______________________?
A. Boiling point elevations
B. Temperature of the feed
C. Rate of heat transfer
D. Ratio of the weight of the thin liquor to thick liquor
Circulation pump is located below the evaporator to___________________?
A. Avoid cavitation
B. Avoid frequent priming
C. Create more suction head
D. None of these
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