The ratio of the workdone on the blades to the energy supplied to the blades, is called
Blading efficiency
Nozzle efficiency
Gross or stage efficiency
Mechanical efficiency
Correct Answer :
A. Blading efficiency
Related Questions
In locomotive boiler, maximum steam pressure is limited to
1 kg/cm²
5 kg/cm²
10 kg/cm²
18 kg/cm²
The friction present between the steam and the nozzle surfaces reduces the heat drop by
10 to 15 %
15 to 25 %
25 to 40 %
40 to 60 %
The indicated thermal efficiency is defined as the
Ratio of thermal efficiency to the Rankine efficiency
Ratio of brake power to the indicated power
Ratio of heat equivalent to indicated power to the energy supplied in steam
Product of thermal efficiency and Rankine efficiency
By compounding the expansion of steam in two or more cylinders, the ratio of expansion
Does not change
Increases
Decreases
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
A supercritical boiler is one that operates above the pressure and temperature of following values
100 kg/cm² and 540°C
1 kg/cm² and 100°C
218 kg/cm² abs and 373°C
218 kg/cm² abs and 540°C
Calorific value of coal is of the order of
200-400 kcal/ kg
800-1200 kcal/ kg
2000-4000 kcal/ kg
5000-8000 kcal/ kg
The state of vapour under saturation condition is described by
Pressure alone
Temperature alone
Pressure and temperature
Pressure and dryness fraction
The expansion of steam in a nozzle follows
Carnot cycle
Rankine cycle
Joule cycle
Stirling cycle
O₂ content in atmospheric air on volume basis is
21 %
23 %
30 %
40 %
Which of the following is a fire tube boiler?
Lancashire boiler
Babcock and Wilcox boiler
Yarrow boiler
None of these
The feed check valve is used in order to
Regulate flow of boiler water
Check level of water in boiler drum
Recirculate unwanted feed water
Allow high pressure feed water to flow to drum and not allow reverse flow to take place
The fittings mounted on the boiler for its proper and safe functioning is a
Water level indicator
Pressure gauge
Safety valve
All of these
Clearance ratio is the ratio of
Clearance volume to the swept volume
Clearance volume to the volume at cut-off
Volume at cut-off to the swept volume
Swept volume to the clearance volume
For combustion of a fuel, following is essential
Correct fuel air ratio
Proper ignition temperature
O₂ to support combustion
All the three above
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
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
Which is not the correct statement about moisture in coal?
Inherent moisture and surface moisture are different things
In some coals moisture may be present up to 40%
Some moisture in coal helps in better burning which is not possible with completely dry coal
It increases thermal efficiency
The critical pressure at which latent heat of vaporisation is zero is
225.65 kgf/ cm²
273 kgf/ cm²
100 kgf/ cm²
1 kgf/ cm²
A stage, in reaction turbine, is represented by
Number of casing
Number of entries of steam
Number of exits of steam
Each row of blades
For the same diameter and thickness of tube, a water tube boiler has ________ heating surface as compared to fire tube boiler.
More
Less
Equal
None of these
A boiler in India should conform to safety regulations of
DIN
BS
ASTM
IBR
The turbine blades are
Straight
Circular
Curved
None of these
Desecration of feed water is carried out because it reduces
Cavitation of boiler feed pumps
Corrosion caused by oxygen
Heat transfer coefficient
pH value of water
The diameter of fire tubes in Cochran boiler is of the order of
2 cm
6 cm
8 cm
12 cm
The action of steam in a steam turbine is
Static
Dynamic
Static and dynamic
Neither static nor dynamic
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
The variation of steam pressure in the nozzle depends upon
Velocity of steam
Specific volume of steam
Dryness fraction of steam
All of these
The latent heat of steam with increase of pressure
Remain same
Increases
Decreases
Behaves unpredictably
In an impulse turbine, steam expands
Wholly in blades
Wholly in nozzle
Partly in the nozzle and partly in blades
None of these