The diameter of fire tube of Cornish boiler compared to its shell is
One half
One third
One fourth
One fifth
Correct Answer :
A. One half
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In designing air preheaters, the important design consideration is that
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Handling and maintenance should be easier
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Above steam dome
Over the combustion chamber
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A safety valve in a locomotive starts leaking. The leaking medium will be
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100 kgf/ cm²
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In case of non-condensing steam engines, the pressure of steam in the cylinder during exhaust stroke is _________ the condenser pressure.
Equal to
Lower than
Higher than
None of these
The Parsons' reaction turbine has
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Identical fixed and moving blades
Fixed and moving blades of different shape
The object of producing draught in a boiler is
To provide an adequate supply of air for the fuel combustion
To exhaust the gases of combustion from the combustion chamber
To discharge the gases of combustion to the atmosphere through the chimney
All of the above
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Smoky chimney exit
Excess air in flue gases
Measuring carbon monoxide in flue gases
Measuring temperature of flue gases at exit of furnace
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Hyperbolic
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None of these
The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.
Same
Less
More
None of these
The draught (in mm of water), for maximum discharge of flue gases through the chimney, is given by (where H = Height of the chimney in metres, and T1 = Absolute temperature of air outside the chimney in K)
T1 /88.25H
88.25H/T1
T1 /176.5H
176.5H/T1
The working pressure range for a LaMont boiler is
0.5 to 10 MN/m²
1 to 15 MN/m²
2.5 to 15 MN/m²
3.5 to 20 MN/m²
The variation of steam pressure in the nozzle depends upon
Velocity of steam
Specific volume of steam
Dryness fraction of steam
All of these
In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine
Lancashire boiler
Locomotive boiler
Babcock and Wilcox boiler
Benson boiler
In a Woolf type compound engine, the high pressure and low pressure cylinders
Have common piston rod
Are set at 90°
Have separate piston rod
Are set in V-arrangement
In a reaction turbine when the degree of reaction is zero, then there is
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No heat drop in fixed blades
Maximum heat drop in moving blades
Maximum heat drop in fixed blades
Pick up the correct statement as regards Cornish boiler and Lancashire boiler
Cornish is fire tube and Lancashire is water tube
Cornish is water tube and Lancashire is fire tube
Cornish has two fire tubes and Lancashire has one
Lancashire has two fire tubes and Cornish has one
The density of supersaturated steam is about __________ that of the ordinary saturated vapour at the corresponding pressure.
Same as
2 times
4 times
8 times
Secondary 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 induced draft fan
The efficiency of the plant __________ with the mechanical draught.
Increases
Decreases
Remains constant
None of these
In a reaction turbine
The steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades
The expansion of steam takes place partly in the fixed blades and partly in the moving blades
The steam is expanded from a high pressure to a condenser pressure in one or more nozzles
The pressure and temperature of steam remains constant
Which of the following statement is wrong?
Locomotive boiler is a water tube boiler
Water tube boilers are internally fired
Lamont boiler is a low pressure water tube boiler
All of the above
Superheating of steam is done at
Constant volume
Constant temperature
Constant pressure
Constant entropy
The shell of the Cochran boiler is made hemispherical
To give maximum space and strength
To withstand the pressure of steam inside the boiler
Both (A) and (B)
None of the above
The diameter of fire tube of Cornish boiler compared to its shell is
One half
One third
One fourth
One fifth
Degree of reaction is defined as the ratio of
Heat drop in fixed blades to the heat drop in moving blades
Heat drop in moving blades to the heat drop in fixed blades
Heat drop in moving blades to the heat drop in fixed blades plus heat drop in moving blades
Heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades