The theoretical indicator diagram of a simple steam engine is based upon the assumption that
There is no pressure drop due to condensation
Steam is admitted at boiler pressure and exhausted at condenser pressure
The expansion (or compression) of the steam is hyperbolic
All of the above
Correct Answer :
D. All of the above
Related Questions
A supercritical boiler is one that operates above the pressure and temperature of following values
100 kg/cm² and 540°C
1 kg/cm² and 100°C
218 kg/cm² abs and 373°C
218 kg/cm² abs and 540°C
Which of the following statement is wrong?
The critical pressure gives the velocity of steam at the throat equal to the velocity of sound.
The flow in the convergent portion of the nozzle is subsonic.
The flow in the divergent portion of the nozzle is supersonic.
To increase the velocity of steam above sonic velocity (supersonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary.
Steam exhaust from high pressure turbine is reheated in
Boiler drums
Superheater tubes
Economiser
A separate coil located in convection path.
Steam turbines are used for
Large marine propulsion
Electric power generation
Direct drive of fans, compressors, pumps
All of these
The length of Cornish boiler varies from
2 to 4.5 m
3 to 5 m
5 to 7.5 m
7 to 9 m
When the total heat of steam is h kJ/kg and the sensible heat of feed water is hf1 kJ/kg, then the factor of evaporation is given by
(h - hf1)/2257
(h + hf1)/2257
(h × hf1)/2257
None of these
The effect of friction on the flow of steam through a nozzle is to
Decrease the mass flow rate and to increase the wetness of steam
Increase the mass flow rate and to increase the exit temperature
Decrease the mass flow rate and to decrease the wetness of steam
Increase the exit temperature without any effect on mass flow rate
The dry saturated steam at very high pressure (150200 kg/cm²) when throttled to atmosphere will become
Wet
Superheated
Remain dry saturated
Dry
Cut-off governing as compared to throttle governing is
Less efficient and less economical
Less efficient and more economical
More efficient and less economical
More efficient and more economical
The flow of steam is supersonic
At the entrance to the nozzle
At the throat of the nozzle
In the convergent portion of the nozzle
In the divergent portion of the nozzle
The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.
More
Less
Same
None of these
The diameter of internal flue tubes of a Lancashire boiler is about _________ that of its shell.
One-fourth
One-third
Two-fifth
One-half
The function of a flywheel is
To convert reciprocating motion of the piston into rotary motion
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To prevent fluctuation of speed
To keep the engine speed uniform at all load conditions
Which of the following is not a boiler mounting?
Blow off cock
Feed check valve
Economiser
Fusible plug
Lancashire boiler is a
Stationary fire tube boiler
Stationary water tube boiler
Water tube boiler with natural/forced circulation
Mobile fire tube boiler
At critical point, i.e. p = 225.65 kg/cm², the latent enthalpy of vaporisation is
Maximum
Minimum
Zero
Depends on temperature also
When the inlet pressure of steam is equal to the exit pressure, then
There is a pressure drop in the nozzle
Fluid flows through the nozzle
Pressure drops and fluid flows through the nozzle
There is no pressure drop and fluid does not flow through the nozzle
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
A wet vapour can be completely specified by
Pressure only
Temperature only
Dryness fraction only
Pressure and dryness fraction
The relative heat absorption for successively added equal areas of boiler convection heating surfaces
Increases
Decreases
Remain unaffected
First increases and then decreases
The dry saturated steam at very low pressure, (510 kg/cm²) when throttled to atmosphere will become
Wet
Superheated
Remain dry saturated
Dry
The radius of a dished head is taken approximately as
One fourth
Half
One
Two
The reheat factor is the ratio of the
Cumulative heat drop to the isentropic heat drop
Isentropic heat drop to the heat supplied
Total useful heat drop to the total isentropic heat drop
None of the above
The function of a crosshead is to guide motion of the _________ and to prevent it from bending.
Piston rod
Connecting rod
Eccentric rod
Valve rod
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
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 %
Which of the following are boiler accessories?
Economiser
Superheater
Both (A) and (B)
None of these
In a Tandem 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
For the same length of stroke and speed of crankshaft, the piston speed for a double acting steam engine is _________ the piston speed of single acting steam engine.
Equal to
Twice
Three times
Four times
If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
Throttling calorimeter
Separating calorimeter
Combined separating and throttling calorimeter
Bucket calorimeter