Which of the following statement is correct?
A horizontal steam engine requires less floor area than a vertical steam engine
The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure
The compound steam engines are generally non-condensing steam engines
All of the above
Correct Answer :
B. The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure
Related Questions
Film boiling occurs at
Very low pressure
Atmospheric pressures
Medium pressures
Very high pressures
The value of diagram factor depends upon
Initial conditions of steam
Back pressure
Initial pressure of steam
All of these
The actual vacuum in a condenser is equal to
Barometric pressure + actual pressure
Barometric pressure - actual pressure
Gauge pressure + atmospheric pressure
Gauge pressure - atmospheric pressure
The specific heat of superheated steam in kcal/kg is generally of the order of
0.1
0.3
0.5
0.8
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
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
The temperature of flue gases at air heater outlet should be
100°C
Above dew point temperature of flue gases
Below dew point temperature of flue gases
Less than wet bulb temperature of flue gases
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
A regenerative steam cycle renders
Increased work output per unit mass of steam
Decreased work output per unit mass of steam
Increased thermal efficiency
Decreased work output per unit mass of steam as well as increased thermal efficiency
O₂ content in atmospheric air on volume basis is
21 %
23 %
30 %
40 %
Tertiary air is the air used to
Provide air around burners for obtaining optimum combustion
Transport and dry the coal
Cool the scanners
Convert CO (formed in lower zone of furnace) into CO₂ at higher zone.
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
Caking coals are those which
Form lumps or masses of coke
Burn freely
Show little or no fusing action
Burn completely
The cylindrical shell of a Lancashire boiler has diameter from
1 to 2 m
1.25 to 2.25 m
1.5 to 2.5 m
1.75 to 2.75 m
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
Fire tube boilers are limited to a maximum working pressure of
0.17 MN/m²
1.7 MN/m²
17 MN/m²
170 MN/m²
The pressure of reheat steam after passing through reheater compared to inlet condition is
More
Less
Equal
May be more or less depending on capacity of reheater
The increase in pressure
Lowers the boiling point of a liquid
Raises the boiling point of a liquid
Does not affects the boiling point of a liquid
Reduces its volume
Latent heat of dry steam at atmospheric pressure is equal to
539 kcal/ kg
539 BTU/ lb
427 kcal/ kg
100 kcal/ kg
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 ratio of heat utilised to produce steam and the heat liberated in furnace is known as
Boiler effectiveness
Boiler evaporative capacity
Factor of evaporation
Boiler efficiency
The critical pressure ratio for initially dry saturated steam is
0.546
0.577
0.582
0.601
In fire tube boilers
Water passes through the tubes which are surrounded by flames and hot gases
The flames and hot gases pass through the tubes which are surrounded by water
Forced circulation takes place
None of these
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 blade friction in the impulse turbine reduces the velocity of steam by __________ while it passes over the blades.
10 to 15 %
15 to 20 %
20 to 30 %
30 to 40 %
The effect of friction in the nozzle __________ dryness fraction of steam.
Has no effect on
Decreases
Increases
None of these
The cylinder dimensions of a compound engine may be designed on the basis of
Equal power developed in each cylinder for uniform turning moment
Equal initial piston loads on all pistons for obtaining same size of piston rod, connecting rod etc. for all cylinders
Equal temperature drop in each cylinder for economy of steam
All of the above
Heating of dry steam above saturation temperature is known as
Enthalpy
Superheating
Super saturation
Latent heat
The amount of water evaporated from feed water at _________ into dry and saturated steam at 100° C at normal atmospheric pressure is called equivalent evaporation from and at 100° C.
0°C
40°C
60°C
100°C
The state of vapour under saturation condition is described by
Pressure alone
Temperature alone
Pressure and temperature
Pressure and dryness fraction