The ratio of the energy required to produce the artificial draught (expressed in metres head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as
Efficiency of the boiler
Efficiency of the chimney
Efficiency of the fan
Power of the boiler
Correct Answer :
B. Efficiency of the chimney
Related Questions
A compound steam engine in which piston rods of high pressure and low pressure cylinders are attached to two different cranks set at 90° to each other, is called
Receiver type compound engine
Tandem type compound engine
Woolf type compound engine
Both (A) and (B)
On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by
Horizontal straight line
Vertical straight line
Straight inclined line
Curved line
The heat balance sheet for the boiler shows the
Complete account of heat supplied by 1 kg of dry fuel and the heat consumed
Moisture present in the fuel
Steam formed by combustion of hydrogen per kg of fuel
All of the above
The length of Lancashire boiler varies from
5 to 6 m
6 to 7 m
7.25 to 9 m
9 to 10 m
The cylinder dimensions of a compound engine may be designed on the basis of
Equal power developed in each cylinder for uniform turning moment
Equal initial piston loads on all pistons for obtaining same size of piston rod, connecting rod etc. for all cylinders
Equal temperature drop in each cylinder for economy of steam
All of the above
The compounding of turbines is done in order to
Reduce speed of rotor
Improve efficiency
Reduce exit losses
All of these
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
The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)
V = 44.72 hd K
V = 44.72 K hd
V = 44.72 K hd
V = 44.72 K hd
Which is not correct statement about the function of furnace?
To provide proper conditions for continuous complete combustion
Mix fuel with air and ignite
Separate ash from coal
Maintain heat supply to prepare and ignite the incoming fuel
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
The shell of the Cochran boiler is made hemispherical
To give maximum space and strength
To withstand the pressure of steam inside the boiler
Both (A) and (B)
None of the above
100% efficiency of a thermal cycle cannot be achieved because of
Frictional losses
It is not possible to achieve 0°K temperature
Leakage
Non availability of ideal substance
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
Steam turbines may be classified according to
Direction of steam flow
Number of stages
Mode of steam action
All of these
With increase in load, radiant superheater has
Drooping characteristic
Linear characteristic
Rising characteristic
Flat characteristic
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
Willian's law states that the steam consumption per hour provided with a throttled governor is proportional to (where I.P. = Indicated power)
1/(I.P)
1/(I.P)²
I.P.
(I.P.)²
The ultimate analysis of fuel lists
Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume
Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight
Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash
The specific heat of superheated steam in kcal/kg is generally of the order of
0.1
0.3
0.5
0.8
In order to compare the capacity of boilers, the feed water temperature and working pressure are taken as
50°C and normal atmospheric pressure
50°C and 1.1 bar pressure
100°C and normal atmospheric pressure
100°C and 1.1 bar pressure
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
The saturation temperature of steam with increase in pressure increases
Linearly
Rapidly first and then slowly
Slowly first and then rapidly
Inversely
The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.
Same
Less
More
None of these
The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ numbers of stages are required.
More
Less
Equal
None of these
Efficiency of Rankine cycle can be increased by
Decreasing initial steam pressure and temperature
Increasing exhaust pressure
Decreasing exhausts pressure
Increasing the expansion ratio
Benson boiler requires
No drum
One drum
Two drums
Three drums
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
The behaviour of coal in a furnace is determined by
The content of sulphur
The content of ash and heating value
The proximate analysis
The exact analysis
The ratio of the volume at cut-off to the swept volume is called
Cut-off ratio
Expansion ratio
Clearance ratio
None of these
Equivalent evaporation is the amount of water evaporated in a boiler from and at
0°C
100°C
Saturation temperature at given pressure
Room temperature