The ratio of the clearance volume to the swept volume is called
Cut-off ratio
Expansion ratio
Clearance ratio
None of these
Correct Answer :
C. Clearance ratio
Related Questions
The pressure of steam in the engine cylinder at the beginning of the stroke is ________ the boiler pressure.
Equal to
Less than
Higher than
None of these
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
In a throttling process
Heat transfer takes place
Work is done by the expanding steam
Internal energy of steam changes
None of the above
In a boiler, the heat is lost
To dry flue gases
In moisture present in the fuel
To steam formed by combustion of hydrogen per kg of fuel
All of the above
Lancashire boiler is
Stationary fire tube boiler
Internally fired boiler
Horizontal boiler
All of these
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
Cut-off ratio is the ratio of
Swept volume to the volume at cut-off
Volume at cut-off to the clearance volume
Volume at cut-off to the swept volume
Clearance volume to the volume at cut-off
Which of the following statement is wrong?
The mechanical draught reduces the height of chimney.
The natural draught reduces the fuel consumption.
A balanced draught is a combination of induced and forced draught.
All of the above
With increase in load, radiant superheater has
Drooping characteristic
Linear characteristic
Rising characteristic
Flat characteristic
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
Latent heat of dry steam at atmospheric pressure is equal to
539 kcal/ kg
539 BTU/ lb
427 kcal/ kg
100 kcal/ kg
The natural draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
A turbine is said to have an axial discharge when the steam leaves the blade tip at _________ to the direction of the blade motion.
60°
90°
180°
270°
De-Laval turbine is a
Single rotor impulse turbine
Multi-rotor impulse turbine
Impulse reaction turbine
None of these
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
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
In recuperative air preheaters, the heat is transferred
From a metal wall from one medium to another
From heating an intermediate material and then heating the air from this material
By direct mixing,
Heat is transferred by bleeding some gases from furnace
When the cross-section of a nozzle increases continuously from entrance to exit, it is called a
Divergent nozzle
Convergent nozzle
Convergent-divergent nozzle
None of these
In impulse turbines, when friction is neglected, the relative velocity of steam at outlet tip of the blade is __________ the relative velocity of steam at inlet tip of the blade.
Equal to
Less than
Greater than
None of these
When steam after doing work in the cylinder passes into a condenser, the engine is said to be a
Slow speed engine
Vertical steam engine
Condensing steam engine
Non-condensing steam engine
Thermal equilibrium means that the flow of steam is
Isothermal
Isentropic
Hyperbolic
Polytropic
The purpose of governing in steam turbines is to
Maintain the speed of the turbine
Reduce the effective heat drop
Reheat the steam and improve its quality
Completely balance against end thrust
Expanding steam to a very low pressure (high vacuum) in steam engines is
Desirable
Economical
Essential
Uneconomical
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
Pick up wrong statement about desired properties of a good fuel
High calorific value
Produce minimum smoke and gases
Ease in storing
High ignition point
The latent heat of steam with increase of pressure
Remain same
Increases
Decreases
Behaves unpredictably
The heat loss in a boiler takes place in the form of
Heat carried away by flue gases
Heat carried away by ash
Moisture present in fuel and steam formed by combustion of hydrogen in fuel
All of the above
The safety valve on boiler drum compared to safety valve on superheater is set at
Same value
Higher value
Lower value
Lower/higher depending on steam flow
Locomotive boiler is of the following type
Multi tubular
Horizontal
Internally fired
All of the above
O₂ content in atmospheric air on volume basis is
21 %
23 %
30 %
40 %