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
Correct Answer :
D. All of the above
Related Questions
Which of the following is not a boiler mounting?
Blow off cock
Feed check valve
Economiser
Fusible plug
Reheating of steam under ideal conditions takes place at constant
Entropy
Enthalpy
Pressure
Temperature
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 relative heat absorption for successively added equal areas of boiler convection heating surfaces
Increases
Decreases
Remain unaffected
First increases and then decreases
The aim of a compound steam engine is
To reduce the ratio of expansion in each cylinder
To reduce the length of stroke
To reduce the temperature range in each cylinder
All of the above
If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
Throttling calorimeter
Separating calorimeter
Combined separating and throttling calorimeter
Bucket calorimeter
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
Which of the following statement is wrong?
Locomotive boiler is a water tube boiler
Water tube boilers are internally fired
Lamont boiler is a low pressure water tube boiler
All of the above
Thermal efficiency of well maintained boiler will be of the order
40 %
50 %
75 %
90 %
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
Alkaline pyrogallate is used in Orsat's apparatus for absorption of
CO₂
CO
O₂
N₂
Which type of boiler can meet rapid changes of load?
Vertical fire tube type
Horizontal fire tube type
Horizontal water tube type
Forced circulation type
In regenerative 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 gas from furnace
The nozzle efficiency is the ratio of
Workdone on the blades to the energy supplied to the blades
Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam
Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
None of the above
The specific volume of steam with increase in pressure decreases
Linearly
Slowly first and then rapidly
Rapidly first and then slowly
Inversely
The fire tubes in a Locomotive boiler has _________ diameter.
4.75 mm
5.47 mm
7.45 mm
47.5 mm
Thermal efficiency of a thermal power plant is of the order of
15 %
20 %
30 %
45 %
The latent heat of steam with increase of pressure
Remain same
Increases
Decreases
Behaves unpredictably
In locomotives, the draught is produced by
Chimney
Induced draft fan
Both combined (A) and (B)
Steam jet draught
The height of chimney in a power plant is governed by
The draft to be created
Limitation of construction facilities
Control of pollution
Quantity of flue gases to be handled
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
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
In order to obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will
Remain unaffected
Improve
Worsen
May improve/worsen depending on size
Pick up the correct statement as regards Cornish boiler and Lancashire boiler
Cornish is fire tube and Lancashire is water tube
Cornish is water tube and Lancashire is fire tube
Cornish has two fire tubes and Lancashire has one
Lancashire has two fire tubes and Cornish has one
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 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 missing quantity per stroke is equal to
Cylinder feed indicated mass of steam
Cylinder feed + indicated mass of steam
Mass of cushion steam + indicated mass of steam
Mass of cushion steam + cylinder feed
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
A double acting steam engine with a cylinder diameter of 190 mm and a stroke of 300 mm has a cut-off of 0.35. The expansion ratio for this engine is nearly
1.05
2.86
6.65
10.05
The turbine blades are
Straight
Circular
Curved
None of these