Related Questions

In regenerative air preheaters, the heat is transferred
A From a metal wall from one medium to another
B From heating an intermediate material and then heating the air from this material
C By direct mixing
D Heat is transferred by bleeding some gas from furnace
Which of the following is not a recuperative furnace?
A Soaking pit
B Reheating furnace
C Steamboiler
D Coke oven
In designing air preheaters, the important design consideration is that
A Approach temperature should be as low as possible
B Handling and maintenance should be easier
C Heat transfer area should be optimum
D Stack gases should not be cooled to the dew point
What is the effect on the performance of the economiser in the thermal power plant boiler, if the feed water temperature is very low due to preheaters being out for repairs or starving of steam supply ?
A It results in corrosion due to the condensation on the flue gas side of the economiser tubes due to handling of low temperature water
B Economiser tube life increases due to handling of low temperature water
C Heat transfer efficiency of economiser increases due to picking up high heat from the flue gases
D Scale formation rate on economiser tubes increases
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
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
When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by
A Conduction
B Convection
C Radiation
D Conduction and convection
When heat is transferred from hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by
A Conduction
B Convection
C Radiation
D Conduction and convection
When heat is transferred by molecular collision, it is referred to as heat transfer by
A Conduction
B Convection
C Radiation
D Scattering
Convective heat transfer, in which heat is transferred by movement of warmed matter is described by
A Fourier's law
B Newton's law of cooling
C Fick's law
D None of these

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