The draught produced by a steam jet issuing from a nozzle placed in the ash-pit under the fire grate of the furnace is called
Induced steam jet draught
Chimney draught
Forced steam jet draught
None of these
Correct Answer :
C. Forced steam jet draught
Related Questions
Primary air is the air used to
Provide air around burners for obtaining optimum combustion
Transport and dry the coal
Convert CO (formed in lower zone of furnace) into CO₂ at higher zone
Air delivered by forced draft fan
In a throttling process
Steam temperature remains constant
Steam pressure remains constant
Steam enthalpy remains constant
Steam entropy remains constant
The impulse turbine rotor efficiency will have a maximum value of 0.5 cos 2α, where α is the nozzle exit flow angle, if the
Blades are equiangular
Blade velocity coefficient is unity
Blades are equiangular and frictionless
Blade solidity is 0.65
The diameter of fire tube of Cornish boiler compared to its shell is
One half
One third
One fourth
One fifth
The amount of water evaporated in kg per kg of fuel burnt is called
Evaporative capacity of a boiler
Equivalent evaporation from and at 100° C
Boiler efficiency
None of these
Willians line for the steam engine is a straight line relationship between the steam consumption per hour and
Indicated power
Brake power
Efficiency
Pressure of steam
Steam in water tube boiler as compared to fire tube boiler
Can be raised rapidly
Is raised at slower rate
Is raised at same rate
Could be raised at fast/slow rate depending on design
Coke is produced by
Pulverising coal in inert atmosphere
Heating wood in a limited supply of air at temperatures below 300°C
Strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel
Enriching carbon in the coal
In accelerated circulation type boiler
Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
Feed pump is employed to supplement natural circulation in water wall type furnace
Water is converted into steam in one pass without any recirculation
Boiler H.P. is defined as the
Steam evaporation rate per kg of fuel fired
Work done in evaporating 1 kg of steam per hour from and at 100°C into dry saturated steam
The evaporation of 15.65 kg of water per hour from and at 100°C into dry saturated steam
Work done by 1 kg of steam at saturation condition
In a De-Laval nozzle expanding superheated steam from 10 bar to 0.1 bar, the pressure at the minimum cross-section (i. e. pressure at throat, p₂) will be
3.3 bar
5.46 bar
8.2 bar
9.9 bar
The diameter of superheated tubes in a locomotive boiler is
13 mm
31 mm
130 mm
230 mm
In a compound steam engine, the first stage of expansion is carried out in a high pressure cylinder whereas the last expansion is completed in low pressure cylinder. The diameter of high pressure cylinder is _________ the low pressure cylinder.
Equal to
Less than
More than
None of these
In a receiver type compound engine, the high pressure and low pressure cylinders
Have common piston rod
Are set at 90°
Have separate piston rods
Are set in V-arrangement
The high pressure boiler is one, which produces steam at a pressure more than
Atmospheric pressure
5 kg/cm²
10 kg/cm²
7580 kg/cm²
In case of condensing steam engines, the pressure of steam in the cylinder during exhaust stroke is _________ the atmospheric pressure.
Equal to
Lower than
Higher than
None of these
A single acting steam engine produces ________ power than that of double acting steam engine.
Equal
Half
Double
Four times
The biggest size of thermal power unit operating in India is
30 MW
60 MW
100 MW
500 MW
In water wall furnace, the heat is transferred to the water walls by
Convection
Radiation
Conduction
Radiation and conduction
The stage efficiency (ηS) is given by (where ηB = Blading efficiency, and ηN = Nozzle efficiency)
ηS = ηB × ηN
ηS = ηB / ηN
ηS = ηN / ηB
None of these
The principal function of a stop valve is 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
Incomplete combustion can be best judged by
Smoky chimney exit
Excess air in flue gases
Measuring carbon monoxide in flue gases
Measuring temperature of flue gases at exit of furnace
Pulverised fuel is used for
Better burning
More calorific value
Less radiation loss
Medium sized units
The actual power supplied by the engine crankshaft is called
Indicated power
Brake power
Frictional power
None of these
Duplex feed pumps are used in small steam boilers. These operate on the principle of
Centrifugal pump
Axial flow pump
Gear pump
Reciprocating pump
The function of a piston rod is
To guide motion of the piston rod and to prevent it from bending
To transfer motion from the piston to the cross head
To convert heat energy of the steam into mechanical work
To exhaust steam from the cylinder at proper moment
The cylinder condensation or missing quantity may be reduced by
The efficient steam jacketing of the cylinder walls
Superheating the steam supplied to the engine cylinder
Keeping the expansion ratio small in each cylinder
All of the above
The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.
More
Less
Same
None of these
For maximum discharge through a chimney, the condition is that height of hot gas column producing the draught should be
One-half the height of chimney
Equal to the height of chimney
Two times the height of chimney
Four times the height of chimney
In a reaction turbine, when steam flows through the moving blades,
Pressure increases while velocity decreases
Pressure decreases while velocity increases
Pressure and velocity both decreases
Pressure and velocity both increases