In a boiler, the heat is lost
To dry flue gases
In moisture present in the fuel
To steam formed by combustion of hydrogen per kg of fuel
All of the above
Correct Answer :
D. All of the above
Related Questions
In a reaction turbine when the degree of reaction is zero, then there is
No heat drop in moving blades
No heat drop in fixed blades
Maximum heat drop in moving blades
Maximum heat drop in fixed blades
The critical pressure ratio is given by (where p₁ = Initial pressure of steam, and p₂ = Pressure of steam at throat or critical pressure)
p₁. p₂
p₁/p₂
p₂/p₁
p₁ + p₂
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
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
Which of the following is not a boiler mounting?
Blow off cock
Feed check valve
Economiser
Fusible plug
During storage, the heating value of coal
Increases
Decreases
Remain constant
May increase or decrease depending upon the method of storage
The purpose of governing in steam turbines is to
Maintain the speed of the turbine
Reduce the effective heat drop
Reheat the steam and improve its quality
Completely balance against end thrust
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
A turbine is said to have an axial discharge when the steam leaves the blade tip at _________ to the direction of the blade motion.
60°
90°
180°
270°
Stage efficiency is also known as
Diagram efficiency
Nozzle efficiency
Gross efficiency
None of these
The discharge is __________ at critical pressure.
Zero
Minimum
Maximum
None of these
The function of a crosshead is to guide motion of the _________ and to prevent it from bending.
Piston rod
Connecting rod
Eccentric rod
Valve rod
The critical pressure ratio for initially wet steam is
0.546
0.577
0.582
0.601
Heating wet steam at constant temperature is heating it at constant
Volume
Pressure
Entropy
Enthalpy
Which of the following varieties of coals is mostly used in steam boilers?
Non-coking bituminous coal
Brown coal
Peat
None of the above
Secondary air is the air used to
Provide air around burners for obtaining optimum combustion
Transport and dry the coal
Convert CO (formed in lower zone of furnace) into CO₂ at higher zone
Air delivered by induced draft fan
The equivalent evaporation is defined as
The ratio of heat actually used in producing the steam to the heat liberated in the furnace
The amount of water evaporated or steam produced in kg per kg of fuel burnt
The amount of water evaporated from and at 100°C into dry and saturated steam
The evaporation of 15.653 kg of water per hour from and at 100°C
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
Steam turbines are used for
Large marine propulsion
Electric power generation
Direct drive of fans, compressors, pumps
All of these
Willians line follows the law (where b = A constant representing the shape of the Willians line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)
I.P. = a × m + b
m = a + b × I.P.
I.P. = b × m + a
m = (b/I.P.) - a
The ratio of the useful heat drop to the isentropic heat drop is called
Condenser efficiency
Nozzle efficiency
Boiler efficiency
Vacuum efficiency
The draught produced by a steam jet issuing from a nozzle placed in the ash-pit under the fire grate of the furnace is called
Induced steam jet draught
Chimney draught
Forced steam jet draught
None of these
The cylinder condensation or missing quantity may be reduced by
The efficient steam jacketing of the cylinder walls
Superheating the steam supplied to the engine cylinder
Keeping the expansion ratio small in each cylinder
All of the above
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)
A safety valve in a locomotive starts leaking. The leaking medium will be
Water
Dry steam
Wet steam
Super heated steam
A nozzle is said to be a convergent nozzle
When the cross-section of the nozzle increases continuously from entrance to exit
When the cross-section of the nozzle decreases continuously from entrance to exit
When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
None 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
The ratio of heat equivalent to brake power to the energy supplied in steam is known as
Mechanical efficiency
Overall efficiency
Indicated thermal efficiency
Brake thermal efficiency
The size of a boiler drum in pulverised fuel fired boiler, as its size and capacity, (steam pressure and flow ratings) increase
Increases
Decreases
Remains unchanged
Increases/decreases depending on steam temperature requirements
Adiabatic process is
Essentially an isentropic process
Non-heat transfer process
Reversible process
Constant temperature process