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.Management Sciences
Category: Chemical Heat Transfer
For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is______________?
A. Nu = 0.023 Re0.8. Pr0.4
B. Nu = (π/2) Gz
C. Nu = (2/π) Gz
D. Nu = 2Gz0.5
“The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium”. This is ______________ law?
A. Kirchoff’s
B. Planck’s
C. Wien’s displacement
D. Stefan-Boltzmann
A _____________ surface has the maximum thermal emissivity out of the following ?
A. Black & smooth
B. Black & rough
C. White & smooth
D. White & rough
Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the________________?
A. Less corrosion problems
B. Flexibility possible in the baffle arrangement
C. Low pressure drop
D. High heat transfer co-efficient
Fqra cold viscous feed, backward feed gives _____________ than forward feed?
A. A higher capacity
B. A lower capacity
C. Lower economy
D. None of these
The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is__________________?
A. 2.36
B. 4.36
C. 120.36
D. Dependent on NRe only
According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor) ?
A. 2f
B. f
C. f/2
D. f/4
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