Superheating of steam is done at
Constant volume
Constant temperature
Constant pressure
Constant entropy
Correct Answer :
C. Constant pressure
Related Questions
In locomotives, the draught is produced by
Chimney
Induced draft fan
Both combined (A) and (B)
Steam jet draught
Which of the following is required for a steam condensing plant?
Condenser
Condensate pump
Air extraction pump
All of these
The maximum heat loss is a boiler occurs due to
Moisture in fuel
Dry flue gases
Steam formation
Unburnt carbon
Fire tube boilers are those in which
Flue gases pass through tubes and water around it
Water passes through the tubes and flue gases around it
Forced circulation takes place
Tubes are laid vertically
The velocity of steam at throat of the nozzle is __________ the velocity of sound.
Equal to
Less than
More than
None of these
Blow off cock in a boiler is used to
Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
Increase the temperature of saturated steam without raising its pressure
The maximum efficiency of a reaction turbine is
2 sin²α/(1 + sin²α)
2 cos²α/(1 + cos²α)
(1 + sin²α)/2 sin²α
(1 + cos²α)/2 cos²α
The fire tubes in a Scotch marine boiler are
Horizontal
Vertical
Inclined
None of these
Which of the following statement is correct?
A fire tube boiler occupies less space than a water tube boiler, for a given power.
Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.
A simple vertical boiler has one fire tube.
All of the above
The maximum discharge of steam through a convergent-divergent nozzle depends upon
Area of nozzle at throat
Initial pressure and volume of steam
Final pressure of steam leaving the nozzle
Both (A) and (B)
The expansion of steam in a nozzle follows
Carnot cycle
Rankine cycle
Joule cycle
Stirling cycle
The radius of a dished head is taken approximately as
One fourth
Half
One
Two
Proximate analysis of fuel is determination of percentage of
Carbon, hydrogen, nitrogen, sulphur, moisture
Fixed carbon, ash, volatile matter, moisture
Higher calorific value
Lower calorific value
With increase in load, convection superheater has
Drooping characteristic
Linear characteristic
Rising characteristic
Flat characteristic
A device used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit, is called
Blow off cock
Stop valve
Superheater
None of these
Heating wet steam at constant temperature is heating it at constant
Volume
Pressure
Entropy
Enthalpy
When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as
Internally fired boiler
Externally fired boiler
Natural circulation boiler
Forced circulation boiler
The balanced draft furnace is one using
Induced draft fan and chimney
Induced draft fan and forced draft fan
Forced draft fan and chimney
Any one of the above
The ratio of heat equivalent to brake power to the energy supplied in steam is known as
Mechanical efficiency
Overall efficiency
Indicated thermal efficiency
Brake thermal efficiency
In a single acting steam engine
The steam is admitted on one side of the piston and one working stroke is produced during each revolution of the crankshaft
The steam is admitted, in turn, on both sides of the piston and one working stroke is produced during each revolution of the crankshaft
The steam is admitted on one side of the piston and two working strokes are produced during each revolution of the crankshaft
The steam is admitted, in turn, on both sides of the piston and two working strokes are produced during each revolution of the crankshaft
Pick up wrong statement about desired properties of a good fuel
High calorific value
Produce minimum smoke and gases
Ease in storing
High ignition point
The Locomotive boiler has
137 fire tubes and 44 superheated tubes
147 fire tubes and 34 superheated tubes
157 fire tubes and 24 superheated tubes
167 fire tubes and 14 superheated tubes
Which is not the correct statement about moisture in coal?
Inherent moisture and surface moisture are different things
In some coals moisture may be present up to 40%
Some moisture in coal helps in better burning which is not possible with completely dry coal
It increases thermal efficiency
In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts. and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is
40 %
25 %
50 %
80 %
A nozzle is said to be a divergent nozzle
When the cross-section of the nozzle increases continuously from entrance to exit
When the cross-section of the nozzle decreases continuously from entrance to exit
When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
None of the above
In regenerative air preheaters, the heat is transferred
From a metal wall from one medium to another
From heating an intermediate material and then heating the air from this material
By direct mixing
Heat is transferred by bleeding some gas from furnace
The natural draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
Ultimate analysis of fuel is determination of percentage of
Carbon, hydrogen, nitrogen, sulphur, moisture
Fixed carbon, ash, volatile matter, moisture
Higher calorific value
Lower calorific value
A device used to increase the temperature of saturated steam without raising its pressure, is called
Blow off cock
Fusible plug
Superheater
Stop valve
The three Ts for good combustion are
Temperature, time, and turbulence
Total air, true fuel, and turbulence
Thorough mixing, total air and temperature
Total air, time, and temperature