The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called
Blading efficiency
Nozzle efficiency
Stage efficiency
Mechanical efficiency
Correct Answer :
C. Stage efficiency
Related Questions
The diameter of a cylindrical shell of a Scotch marine boiler varies from
1.5 to 2 m
2.5 to 3.5 m
3.5 to 4.5 m
None of these
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
Multi-stage steam turbines are of the
Velocity compounded type
Reaction type
Pressure compounded type
All of these
Which of the following compound steam engine requires a smaller flywheel?
Receiver type
Tandem type
Woolf type
All of these
The efficiency of steam turbines may be improved by
Reheating of steam
Regenerative feed heating
Binary vapour plant
Any one of these
Thermal equilibrium means that the flow of steam is
Isothermal
Isentropic
Hyperbolic
Polytropic
The object of producing draught in a boiler is
To provide an adequate supply of air for the fuel combustion
To exhaust the gases of combustion from the combustion chamber
To discharge the gases of combustion to the atmosphere through the chimney
All of the above
The efficiency of the plant __________ with the mechanical draught.
Increases
Decreases
Remains constant
None of these
The length of Lancashire boiler varies from
5 to 6 m
6 to 7 m
7.25 to 9 m
9 to 10 m
Over fire burning is the phenomenon of
Supply of excess, air
Supply of excess coal
Burning CO and unburnts in upper zone of furnace by supplying more air
Fuel bed firing
Relative percentage of heat absorbed through the heat transfer of (i) Furnace water wall (ii) Boiler tank (iii) Superheater (iv) Economiser (v) Air-heater of a typical boiler of 200 MW capacity would be of the order of
48 : 20 : 15 : 7 : 10
10 : 7 : 15 : 20 : 48
20 : 48 : 7 : 15 : 10
7 : 15 : 20 : 10 : 48
An economiser in a boiler
Increases steam pressure
Increases steam flow
Decreases fuel consumption
Decreases steam pressure
On Millier chart, the constant pressure lines
Diverge from left to right
Diverge from right to left
Are equally spaced throughout
First rise up and then fall
The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)
Remains constant
Decreases
Increases
None of these
Incomplete combustion can be best judged by
Smoky chimney exit
Excess air in flue gases
Measuring carbon monoxide in flue gases
Measuring temperature of flue gases at exit of furnace
Green coal, in order to be burnt, must be
Heated sufficiently
Burnt in excess air
Heated to its ignition point
Burnt as powder
In locomotive boiler, maximum steam pressure is limited to
1 kg/cm²
5 kg/cm²
10 kg/cm²
18 kg/cm²
Gradually increasing temperature of flue gases at inlet to chimney for given steam outputs is an indication of
Higher effectiveness of boiler
High calorific value coal being burnt
Fouling of heat transfer surfaces
Raising of steam temperature
The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called
Condenser efficiency
Vacuum efficiency
Nozzle efficiency
Boiler efficiency
The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called
Blading efficiency
Nozzle efficiency
Stage efficiency
Mechanical efficiency
Efficiency of Rankine cycle can be increased by
Decreasing initial steam pressure and temperature
Increasing exhaust pressure
Decreasing exhausts pressure
Increasing the expansion ratio
In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be
160/3 m/s
320/3 m/s
640/3 m/s
640 m/s
The function of a valve rod is
To provide reciprocating motion to the slide valve
To convert reciprocating motion of the piston into rotary motion of the crank
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To provide simple harmonic motion to the D-slide valve
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
The fusible plug in small boilers is located
In the drum
In the fire tubes
Above steam dome
Over the combustion chamber
The shell diameter and length of locomotive boiler are
1.5 m, 4 m
1.5 m, 6 m
1 m, 4 m
2 m, 4 m
In a reaction turbine, when steam flows through the fixed blades,
Pressure increases while velocity decreases
Pressure decreases while velocity increases
Pressure and velocity both decreases
Pressure and velocity both increases
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
One kilowatt-hour energy is equivalent to
1000 J
360 kJ
3600 kJ
3600 kW/sec
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