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
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
The heat recoverable from flue gases of furnaces depends on the
A Thermal efficiency of furnace
B Quantity of flue gases
C Flue gas temperature drop through the furnace
D All of the above
Which of the following furnaces will have maximum thermal efficiency?
A Soaking pits
B Walking beam reheating furnace
C Boiler furnace
D Rotary kilns
By the use of which of the following, high frequency power supply for induction furnaces can be obtained?
A Coreless transformers
B Current transformers
C Motor-generator set
D Multiphase transformer
Which of the following device is best suited for measuring the temperature inside metallurgical furnaces?
A Pyrometer
B Thermocouple
C Thermometer
D Thermistor
Which of the following methods is used to control temperature in resistance furnaces?
A Variation of resistance
B Variation of voltage
C Periodical switching on and off of the supply
D All of the above methods

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