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
Correct Answer :
C. Pressure and velocity both decreases
Related Questions
The maximum discharge through a chimney occurs when the height of chimney is
Infinitely long
Around 200 meters
Equal to the height of the hot gas column producing draught
Outside temperature is very low
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
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
When the circulation of water, in a boiler, is by a centrifugal pump, then the boiler is known as
Internally fired boiler
Externally fired boiler
Natural circulation boiler
Forced circulation boiler
When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.
Increases
Decreases
Remain same
None of these
Water tube boilers are those in which
Flue gases pass through tubes and water around it
Water passes through the tubes and flue gases around it
Work is done during adiabatic expansion
Change in enthalpy
Cochran boiler is a
Horizontal fire tube boiler
Horizontal water tube boiler
Vertical water tube boiler
Vertical fire tube boiler
Maximum energy loss in a boiler occurs due to
Unburnt carbon in ash
Incomplete combustion
Ash content
Flue gases
In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be
56 %
63 %
74 %
78 %
The equivalent evaporation of a boiler is a measure to compare
The given boiler with the model
The two different boilers of the same make
Two different makes of boilers operating under the same operating conditions
Any type of boilers operating under any conditions
The selection of type and size of a steam boiler depends upon
The power required and working pressure
The geographical position of the power house
The fuel and water available
All of the above
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
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
A fusible plug is fitted in small boilers in order to
Avoid excessive build up of pressure
Avoid explosion
Extinguish fire if water level in the boiler falls below alarming limit
Control steam dome
In a uniflow engine
Steam enters and exhausts through the same port
Steam enters at one end and exhausts at the centre
Steam enters at the centre and exhausts at the other end
None of the above
De-Laval turbine is a
Single rotor impulse turbine
Multi-rotor impulse turbine
Impulse reaction turbine
None of these
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
The number of water level indicators in a boiler are generally _________ in number.
One
Two
Three
Four
Which of the following is not a boiler mounting?
Blow off cock
Feed check valve
Economiser
Fusible plug
The impulse turbine rotor efficiency will have a maximum value of 0.5 cos 2α, where α is the nozzle exit flow angle, if the
Blades are equiangular
Blade velocity coefficient is unity
Blades are equiangular and frictionless
Blade solidity is 0.65
Locomotive type' boiler is
Horizontal multi-tubular water tube boiler
Water wall enclosed furnace type
Vertical tubular fire tube type
Horizontal multi-tubular fire tube type
In accelerated circulation type boiler
Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
Feed pump is employed to supplement natural circulation in water wall type furnace
Water is converted into steam in one pass without any recirculation
Which of the following statement is wrong?
Locomotive boiler is a water tube boiler
Water tube boilers are internally fired
Lamont boiler is a low pressure water tube boiler
All of the above
Proximate analysis of fuel is determination of percentage of
Carbon, hydrogen, nitrogen, sulphur, moisture
Fixed carbon, ash, volatile matter, moisture
Higher calorific value
Lower calorific value
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
De-Laval turbines are mostly used
Where low speeds are required
For small power purposes and low speeds
For large power purposes
For small power purposes and high speeds
A closed vessel made of steel and used for the generation of steam is called a
Steam boiler
Steam turbine
Steam condenser
Steam injector
O₂ content in atmospheric air on volume basis is
21 %
23 %
30 %
40 %
A safety valve mainly used with locomotive and marine boilers is
Lever safety valve
Dead weight safety valve
High steam and low water safety valve
Spring loaded safety valve
The ratio of the clearance volume to the swept volume is called
Cut-off ratio
Expansion ratio
Clearance ratio
None of these