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.Management Sciences
Category: Chemical Heat Transfer
Unsteady state heat conduction occurs, when_______________?
A. Temperature distribution is independent of time
B. Temperature distribution is dependent on time
C. Heat flows in one direction only
D. Three dimensional heat flow is concerned
LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface area required is the least in the ______________ flow?
A. Parallel
B. Mixed
C. Counter flow
D. Same in either A , B. or C.
With increase in temperature, the thermal conductivity of fresh lubricating oil ___________________?
A. Increases
B. Decreases
C. Remains unchanged
D. May increase or decrease; depends on its composition
Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger ?
A. Corrosiveness
B. Fouling characteristic
C. Viscosity
D. None of these
The statement that “maximum wavelength of radiation is inversely proportional to the temperature” is ______________ law?
A. Stefan-Boltzmann’s
B. Planck’s
C. Wien’s displacement
D. None of these
Tube pitch is the _______________ of tube diameters and the clearances?
A. Sum
B. Difference
C. Ratio
D. None of these
In a shell and tube heat exchanger, square pitch compared to triangular pitch__________________?
A. Gives a higher shell side pressure drop
B. Gives a lower shell side pressure drop
C. Can pack more surface area into a shell of given diameter
D. None of these
A BTU/hr.ft.2 °F is equal to_________________?
A. 1 kcal/hr. m2°C
B. 4.88 kcal/hr. m.2°C
C. 1 kcal/hr. m2.°K
D. None of these
In forced convection, the heat transfer depends on _______________?
A. Re, Pr
B. Re, Gr
C. Mainly Gr
D. Re only
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