The reheat factor depends upon
Initial pressure and superheat
Exit pressure
Turbine stage efficiency
All of these
Correct Answer :
D. All of these
Related Questions
Boiler stays are used to
Prevent flat surfaces under pressure from tearing apart
Take care of failure in shear
Take care of failure in compression
Provide support for boiler
Which of the following gases has the highest calorific value?
Producer gas
Coal gas
Water gas
Blast furnace gas
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
A condenser in a steam power plant
Increases expansion ratio of steam
Reduces back pressure of steam
Reduces temperature of exhaust steam
All of these
The critical pressure ratio is given by (where p₁ = Initial pressure of steam, and p₂ = Pressure of steam at throat or critical pressure)
p₁. p₂
p₁/p₂
p₂/p₁
p₁ + p₂
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
Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
Increases
Decreases
Remain unaffected
First increases and then decreases
When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be
Choked
Under-damping
Over-damping
None of these
A safety valve in a locomotive starts leaking. The leaking medium will be
Water
Dry steam
Wet steam
Super heated steam
The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop
Remains the same
Increases
Decreases
Is unpredictable
Water at pressure of 4 kg/cm² and 160°C temperature when exposed to atmosphere will
Boil
Flash i.e. get converted into steam
Remain as it was
Cool down
A device used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit, is called
Blow off cock
Stop valve
Superheater
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
The critical pressure gives the velocity of steam at the throat
Equal to the velocity of sound
Less than the velocity of sound
More than the velocity of sound
None of these
In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is
Low
Very low
High
Very high
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
Pulverised fuel is used for
Better burning
More calorific value
Less radiation loss
Medium sized units
A throttle governed steam engine develops 15 kW with 280 kg per hour of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW will be nearly
150 kg/h
210 kg/h
280 kg/h
340 kg/h
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
In an impulse turbine, steam expands
Wholly in blades
Wholly in nozzle
Partly in the nozzle and partly in blades
None of these
In an impulse turbine
The steam is expanded in nozzles only and there is a pressure drop and heat drop
The steam is expanded both in fixed and moving blades continuously
The steam is expanded in moving blades only
The pressure and temperature of steam remains constant
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
Hard coke is used in
Cement industry
Thermal power plant
Blast furnace
Domestic use
The forced circulation of water does not take place in
LaMont boiler
Lancashire boiler
Velox boiler
Benson boiler
The maximum heat loss is a boiler occurs due to
Moisture in fuel
Dry flue gases
Steam formation
Unburnt carbon
A wet vapour can be completely specified by
Pressure only
Temperature only
Dryness fraction only
Pressure and dryness fraction
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
Green coal, in order to be burnt, must be
Heated sufficiently
Burnt in excess air
Heated to its ignition point
Burnt as powder
For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has
More heating surface
Less heating surface
Equal heating surface
Heating surface depends on other parameters
Stage efficiency is also known as
Diagram efficiency
Nozzle efficiency
Gross efficiency
None of these