Related Questions

The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows __________ law.
A Hyperbolic
B Parabolic
C Linear
D Logarithmic
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface tempeature follows __________ law.
A Parabolic
B Hyperbolic
C Linear
D Logarithmic
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
A Increases
B Decreases
C Remains constant
D Passes through a maxima
Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is
A Finned tube heat exchanger with air inside and steam outside
B Finned tube heat exchanger with air outside and steam inside
C Shell and tube heat exchanger with air inside tubes and steam on shell side
D Shell and tube heat exchanger with air on shell side and steam inside tubes
The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the
A Heating volume
B Heat transfer area
C Nusselt number
D None of these
Which of the following is a case of steady state heat transfer?
A I.C. engine
B Air preheaters
C Heating of building in winter
D None of the above
Which of the following situations can be approximated to a steady state heat transfer system?
A A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmosheric air at 35°C
B 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless-steel pipe exposed to atmospheric air at 35°C
C Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C
D A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C
In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of
A Concentrations
B Chemical potentials
C Activity co-efficients
D Mass transfer co-efficients

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