The performance of a boiler is measured by the
Amount of water evaporated per hour
Steam produced in kg/h
Steam produced in kg/kg of fuel burnt
All of these
Correct Answer :
D. All of these
Related Questions
The three Ts for good combustion are
Temperature, time, and turbulence
Total air, true fuel, and turbulence
Thorough mixing, total air and temperature
Total air, time, and temperature
The economiser is used in boilers to
Increase thermal efficiency of boiler
Economise on fuel
Extract heat from the exhaust flue gases
Increase flue gas temperature
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
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
The pressure of steam __________ while flowing through a nozzle.
Increases
Decreases
Remains constant
None of these
A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be
79 m/s
188 m/s
450 m/s
900 m/s
The basic purpose of drum in boiler is to
Serve as storage of steam
Serve as storage of feed water for water wall
Remove salts from water
Separate steam from water
The ratio of the isentropic heat drop to the heat supplied, is called
Reheat factor
Stage efficiency
Internal efficiency
Rankine efficiency
Size of boiler tubes is specified by
Mean diameter and thickness
Inside diameter and thickness
Outside diameter and thickness
Outside diameter and inside diameter
The ratio of heat utilised to produce steam and the heat liberated in furnace is known as
Boiler effectiveness
Boiler evaporative capacity
Factor of evaporation
Boiler efficiency
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
Fire 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
Forced circulation takes place
Tubes are laid vertically
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
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
A vessel into which the steam is exhausted and condensed after doing work in an engine cylinder or turbine is known as
Steam condenser
Steam boiler
Steam preheater
Economiser
In cross compounding, the cylinders are arranged
Side by side and each cylinder has common piston, connecting rod and crank
Side by side and each cylinder has separate piston, connecting rod and crank
At 90° and each cylinder has common piston, connecting rod and crank
At 90° and each cylinder has separate piston, connecting rod and crank
An air preheater
Increases evaporative capacity of the boiler
Increases the efficiency of the boiler
Enables low grade fuel to be burnt
All of the above
The basic job of feed water treatment in boilers is to overcome the problem of
Corrosion
Scale
Carryover
All of the above
Degree of reaction is defined as the ratio of
Heat drop in fixed blades to the heat drop in moving blades
Heat drop in moving blades to the heat drop in fixed blades
Heat drop in moving blades to the heat drop in fixed blades plus heat drop in moving blades
Heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades
The critical pressure ratio (p₂/p₁) is given by
(p₂/p₁) = [2/(n - 1)] n/(n + 1)
(p₂/p₁) = [2/(n + 1)] n/(n-1)
(p₂/p₁) = [(n - 1)/2] n + (1/n)
(p₂/p₁) = [(n + 1)/2] n - (1/n)
The diameter of Cornish boiler is of the order of
12 m
1.52.5 m
23 m
2.53.5 m
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
Which is not correct statement about pulverised fuel firing?
High burning rate is possible
Heat release can be easily controlled
Fuel burns economically
It is the best technique for burning high ash content fuel having low fusion ash
The turbine blades are
Straight
Circular
Curved
None of these
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
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
In a throttling process
Steam temperature remains constant
Steam pressure remains constant
Steam enthalpy remains constant
Steam entropy remains constant
Blow off cock in a boiler is used to
Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
Increase the temperature of saturated steam without raising its pressure
The velocity of steam at throat of the nozzle is __________ the velocity of sound.
Equal to
Less than
More than
None of these
O₂ content in atmospheric air on weight basis is
21 %
23 %
30 %
40 %