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WorksheetsBoiler and Steam Turbine
Total questions: 46
Worksheet time: 46mins
Name
Class
Date
1.
The equivalent evaporation (kg/hr) of a boiler producing 2000 kg/hr ofsteam withenthalpy content of 2426 kJ/kg from feed water at temperature40°C (liquid enthalpy= 168 kJ/kg, enthalpy of vaporisation of water at100°C = 2258 kJ/kg) is
a)
2000
b)
2149
c)
1682
d)
1649
2.
Heat is mainly transferred by conduction, convection and radiation in
a)
Insulated pipes carrying hot water
b)
Refrigerator freezer coil
c)
Boiler furnaces
d)
condensation of steam in a condenser
3.
The shell diameter and length of locomotive boiler are
a)
1.5 m, 4 m
b)
1.5 m, 6 m
c)
1 m, 4 m
d)
2 m, 4 m
4.
Which one of the following statements is not true for a supercritical steam generator?
a)
It has a very small drum compared to a conventional boiler
b)
A supercritical pressure plant has higher efficiency than a subcriticalpressure plant
c)
The feed pressure required is very high, almost 1.2 to 1.4 times the boilerpressure
d)
As it requires absolutely pure feed water, preparation of feed water is moreimportant than in a subcritical pressure boiler
5.
The distinguishing feature of Velox boiler is that it
a)
Is drumless
b)
uses supersonic
c)
Operates under supercritical pressure
d)
uses indirect heating
6.
For a single stage impulse turbine with a rotor diameter of 2 m and aspeed of 3000 rpmwhen the nozzle angle is 20 , the optimum velocity ofsteam in m/s is
a)
314
b)
356
c)
668
d)
711
7.
In steam turbine terminology, diaphragm refers to
a)
Separating wall between rotors carrying nozzles
b)
The ring of guide blades between rotors
c)
A partition between low and high pressure sides
d)
The flange connecting the turbine exit to the condenser
8.
A single-stage impulse turbine with a diameter of 120 cm runs at 3000 rpm.If the bladespeed ratio is 0.42 then, the inlet velocity of steam will be
a)
79 m/s
b)
188m/s
c)
450 m/s
d)
900 m/s
9.
Which one of the following is used to bring down the speed of an impulse steam turbine to practical limits?
a)
Differential Gear
b)
Compounding of the turbine
c)
A large flywheel
d)
A gear box
10.
Why is compounding of steam turbines done?
a)
To improve efficiency
b)
To reduce the speed of rotor
c)
To reduce exit losses
d)
To increase the turbine output
11.
On Mollier chart, flow th rough t urbine is represented by'
a)
horizontal straight line
b)
vertical straight line
c)
straight inclined line
d)
curved line
12.
While steam expands in t urbines, theoretically t he entropy
a)
remains constant
b)
increases
c)
decreases
d)
behaves unpredictably
13.
Equiva lent evaporation of water is the evaporation "for a feed water supply at 100°C
a)
and its corresponding conversion i nto dry sat urated steam at toooc and 1.033 kg/cm2
b)
and its corresponding conversion i nto dry steam at desired boiler pressure
c)
conversion i nto steam at atmospheric condition
d)
none of the above.
14.
The evaporation of 15.653 kg of water per hour from and at 100 degree celcius is called
a)
evaporative capacity
b)
factor of evaporation
c)
equivalent evaporation
d)
one boiler h.p .
15.
Cochran boiler is a
a)
horizontal fire-tube boiler
b)
horizontal water-tube boiler
c)
veritcal water-tube boiler
d)
vertical fire tube boiler
16.
The lenght of Cornish boiler is of th e ord er of
a)
2-4m
b)
3·5 m
c)
5-7.5 m
d)
7-9 m
17.
Locomotive type boiler is
a)
hortzontal multitubular water tube boiler
b)
water wall enclosed furnace type
c)
vertical tubular fire tube type
d)
hortzontal multi-tubular fire tube type
18.
Which of the following substance will have same percentage in both proximate and ultimate analysis
a)
ash
b)
volatile matter
c)
moisture
d)
hydrogen
19.
The biggest size of thermal power unit operating in India is
a)
30 MW
b)
60 MW
c)
100 MW
d)
500 MW
20.
Which of the coal has highest calorific value ?
a)
anthracite coal
b)
bituminous coal
c)
lignite
d)
peat
21.
The crown of t he fire box is mad e hemispherical in order to
a)
give maximum space
b)
give max imum strength
c)
resist intense heat in fire box
d)
withstand pressure inside boiler
22.
The basic purpose of drum in boiler is to
a)
separate steam from water
b)
serve as storage of feed water for water wall
c)
remove salts from water
d)
serve as storage space for steam
23.
Which of the following varieties of coals is mostly used in steam boilers
a)
non-coking bituminous coal
b)
none
c)
brown coal
d)
peat
24.
A boiler in India should conform to safety regulations of
a)
DIN
b)
IBR
c)
ASTM
d)
BS
25.
The fusible plug in small boilers is located
a)
in the drum
b)
in the fire tubes
c)
above steam dome
d)
over the combustion chamber
26.
Fusible plug for boilers is made of fu sible metal containing tin, lead, and
a)
bismuth
b)
copper
c)
aluminium
d)
nickel
27.
Steam in water t ube boiler as compared to fire tube boiler
a)
can be raised rapidly
b)
is raised at slower rate
c)
is raised at same rate
d)
could be r aised at fast/slow rate depending on d esi
28.
Thermal efficiency of well mainta ined boiler will be of the order
a)
0.2
b)
0.4
c)
0.5
d)
0.9
29.
Which type of boiler can meet rapid changes of load
a)
forced circulation type.
b)
vertical water tube type
c)
horizontal fire tube type
d)
vertical fire tube type
30.
Fire tube boilers a re lim ited to a maximum design working pressure of
a)
1 kg/cm2
b)
6 kg/cm2
c)
17 kg/cm 2
d)
100 kg/cm2
31.
For Parson’s reaction steam turbine, degree of reaction is
a)
0.75
b)
1
c)
0.5
d)
0.6
32.
Parson’s turbine is
a)
pressure compounded steam turbine
b)
simple single wheel, impulse steam turbine
c)
simple single wheel reaction steam turbine
d)
multi wheel reaction steam turbine
33.
Rateau steam turbine is
a)
reaction steam turbine
b)
velocity compounded impulse steam turbine
c)
pressure compounded impulse steam turbine
d)
pressure velocity compounded steam turbine
34.
The modern steam turbines are
a)
impulse turbines
b)
reaction turbines
c)
impulse-reaction turbines
d)
none of the above
35.
A Curtis stage, Rateau stage and a 50% reaction stage in a steam turbine<br />are examples of
a)
Different types of impulse stages
b)
Different types of reaction stages
c)
A simple impulse stage, a velocity compounded impulse stage and reaction stage
d)
A velocity compounded impulse stage, a simple impulse stage and a reaction<br />stage
36.
In an ideal impulse turbine, the
a)
Absolute velocity at the inlet of moving blade is equal to that at the outlet
b)
Relative velocity at the inlet of the moving blade is equal to that at the outlet
c)
Axial, velocity at the inlet is equal to that at the outlet
d)
Whirl velocity at the inlet is equal to that at the outlet
37.
Steam enters a De Laval steam turbine with an inlet velocity of 30 m/s and leaves with an outlet velocity of 10 m/s. The work done by 1kg of steam is
a)
400 Nm
b)
600 Nm
c)
800 Nm
d)
1200Nm
38.
An impulse turbine produces 50 kW of power when the blade mean speed is 400 m/s. What is the rate of change of momentum tangential to the rotor?
a)
200 N
b)
175 N
c)
150 N
d)
125 N
39.
A single-stage impulse turbine with a diameter of 120 cm runs at 3000 rpm.If the blade speed ratio is 0.42 then, the inlet velocity of steam will be
a)
79 m/s
b)
188m/s
c)
450 m/s
d)
900 m/s
40.
If the enthalpy drop in the moving blades and fixed blades of a steam turbine is 10 kJ/kg and 15 kJ/kg respectively then what is the degree of reaction?
a)
0.67
b)
0.6
c)
0.4
d)
0.33
41.
The degree of reaction of an impulse turbine:
a)
Is less than zero
b)
is greater than zero
c)
is equal to zero
d)
increases with steam velocity at the inlet
42.
Which one of the following relationship between angles of fixed blades and moving blades corresponds to that of Parson's turbine?
a)
α1 = α2
b)
α1 = β2
c)
α1 =β2
d)
β1 = β2
43.
Given, ηs = stage efficiency ; ηn = nozzle efficiency ; ηb = blade efficiency ; Which one of the following is correct?
a)
ηn = ηbηs
b)
ηb = ηsηn
c)
ηb × ηn × ηs =1
d)
ηs = ηbηn
44.
Assertion (A): Throttle governing is used only in small steam turbines. Reason(R): At part loads, the efficiency of steam turbine reduces considerably with throttle governing
a)
Both A and R are individually true and R is the correct explanation of A
b)
Both A and R are individually true but R is not the correct explanation of A
c)
A is true but R is false
d)
A is false but R is true
45.
Governing of steam turbines can be done by the following
a)
Nozzle control
b)
Throttle control
c)
Providing additional value and passage
46.
Efficiency of nozzle governed turbine is affected mainly by losses due to
a)
Partial admission
b)
throttling
c)
Inter-stage pressure drop
d)
condensation in last stages
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