Pick up the wrong statement about critical condition of steam
Latent heat is zero
Liquid directly becomes steam
Specific volume of steam and liquid is same
This is the maximum pressure limit
Correct Answer :
D. This is the maximum pressure limit
Related Questions
The reheat factor depends upon
Initial pressure and superheat
Exit pressure
Turbine stage efficiency
All of these
Which of the following is steam dial?
Non-coking bituminous coal
Brown coal
Pulverised coal
Coking bituminous coal
The effect of bleeding is that
It increases the thermodynamic efficiency of the turbine
Boiler is supplied with hot water
It decreases the power developed by the turbine
All of the above
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
Hard coke is produced by carburisation of coal at
Atmospheric temperature
500-600°C
700-850°C
950-1100°C
In order to obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will
Remain unaffected
Improve
Worsen
May improve/worsen depending on size
The change in internal energy in steam engines equals to
Work done during the Rankine cycle
Work done during compression
Work done during adiabatic expansion
Change in enthalpy
For combustion of a fuel, following is essential
Correct fuel air ratio
Proper ignition temperature
O₂ to support combustion
All the three above
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
On Mollier chart, flow through turbine is represented by
Horizontal straight line
Vertical straight line
Straight inclined line
Curved line
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
The pressure at which latent heat of vaporisation of water is zero, is
Below atmospheric pressure
1 kg/cm²
100 kg/cm²
225.6 kg/cm²
The major axis of elliptical manholes on the shell should be provided
Longitudinally
Circumferentially
On dished end
Anywhere
The function of a valve rod is
To provide reciprocating motion to the slide valve
To convert reciprocating motion of the piston into rotary motion of the crank
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To provide simple harmonic motion to the D-slide valve
The variation of steam pressure in the nozzle depends upon
Velocity of steam
Specific volume of steam
Dryness fraction of steam
All of these
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
In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be
160/3 m/s
320/3 m/s
640/3 m/s
640 m/s
A stage, in reaction turbine, is represented by
Number of casing
Number of entries of steam
Number of exits of steam
Each row of blades
The diameter of fire tubes in Cochran boiler is of the order of
2 cm
6 cm
8 cm
12 cm
Caking coals are those which
Form lumps or masses of coke
Burn freely
Show little or no fusing action
Burn completely
The diameters of fire tubes and superheater tubes in locomotive boiler are
47.5 mm, 130 mm
32.5 mm, 180 mm
65.5 mm, 210 mm
24.5 mm, 65 mm
In reaction turbines, the axial thrust is due to
Pressure drop across the rotor
Change in axial velocity
Both (A) and (B)
None of these
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
Which of the following is a fire tube boiler?
Locomotive boiler
Babcock and Wilcox boiler
Stirling boiler
All of the above
The crown of the fire box is made hemispherical in order to
Give maximum space
Give maximum strength
Withstand pressure inside boiler
Resist intense heat in fire box
A safety valve in a locomotive starts leaking. The leaking medium will be
Water
Dry steam
Wet steam
Super heated steam
The high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks
180° to each other
90° to each other
0° to each other
None of these
The chimney draught varies with
Climatic conditions
Temperature of furnace gases
Height of chimney
All of these
If partial pressure of air and steam be pa and ps respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to
ps - pa
pa - ps
pa + ps
None of these
Pulverised fuel is used for
Better burning
More calorific value
Less radiation loss
Medium sized units