Related Questions

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
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
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
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
The term "cooling range" in a cooling tower refers to the difference in the temperature of
A Cold water leaving the tower and the wet bulb temperature of the surrounding air
B Hot water entering the tower and the wet bulb temperature of the surrounding air
C Hot water entering the tower and the cooled water leaving the tower
D None of these
The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called
A Condenser efficiency
B Vacuum efficiency
C Nozzle efficiency
D Boiler efficiency
The heat flux in the nucleate boiling regimes is proportional to (where, ΔT = excess temperature)
A (ΔT)2
B (ΔT)4
C (ΔT)3
D $$\sqrt {\Delta {\text{T}}} $$
Stress may be expressed in Newtons
A Per millimetre square (N/mm2)
B Per centimetre square (N/cm2)
C Per metre square (N/m2)
D None of these
The initial tension (in newtons) in a bolt used for making a fluid tight joint like steam engine cover joints, is calculated by the relation (where d = Nominal diameter of bolt in mm)
A 1420 d
B 1680 d
C 2080 d
D 2840 d
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

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