1.
Consider the following statements:
1.
Cavitations occur in turbine at the exit (inlet
of draft tube).
2.
In compressor (or, pump), cavitations occur at
the inlet of the compressor.
3.
Bell Coleman Cycle is a power consuming cycle.
4.
Fluid energy in Brayton Cycle is increased.
Which of the statements given above is/are correct?
a)
1 and 2 only
b)
1, 2 and 3 only
c)
1, 2 and 4 only
d)
All are correct
2.
Chance of flow separation is more in
1.
turbinea
2.
compressor
3.
where pressure gradient is negative
4.
where pressure gradient is positive
select
the correct answer using code given below
a.
1 & 3 b. 2 & 4 c. 1 & 4 d.
2 & 3
3.
Match List-I
with List-II and the correct answer
using the code given below
List-I
A.
Air
B.
Vapour
C.
Stem
List-II
1.
γ = 1.4
2.
γ = 1.3
3.
γ = 1.88
Code
A
|
B
|
C
|
|
a.
|
1
|
2
|
3
|
b.
|
1
|
3
|
2
|
c.
|
3
|
2
|
1
|
d.
|
3
|
1
|
2
|
4.
Power consuming
cycle in T-s diagram is
a.
clockwise
b.
anticlockwise
c.
both possible
d.
Power consuming
cycle has no T-s diagram
5.
Which statement is NOT true for vapour power
cycle
a.
Rankine Cycle is an example of it.
b.
This is practical working cycle for thermal
power plants.
c.
It always has a condenser.
d.
The working fluid remains in liquid phase
throughout the cycle.
6.
Which statement is NOT correct for gas cycle
a.
The working fluid remains in gasses phase
throughout the cycle.
b.
Brayton Cycle and Bell Coleman Cycle is an
example of it.
c.
It always has a condenser.
d.
Pressure ratio of this power plant is 10 to 15
bar.
7.
Which statement is true for vapour power cycle
a.
The working fluid remains in gasses phase
throughout the cycle.
b.
The working fluid remains in liquid phase
throughout the cycle.
c.
The working fluid remains in solid gasses phase
throughout the cycle.
d.
The working fluid remains in liquid phase in one
part of the cycle and remains in gasses phase in another part of cycle
8.
Which statement is NOT true for open cycle
a.
New working fluid is admitted at the end of each
cycle
b.
The working fluid must be air.
c.
Mass from outlet of turbine is more than mass
inlet in compressor.
d.
It has Better efficiency.
9.
Which statement is NOT true for close cycle
a.
Same working fluid is recirculated again and again
in each cycle.
b.
Any working fluid (like, He, Ar, etc) can be
used.
c.
It has Better efficiency.
d.
It always has an intercooler.
10.
Which statement is NOT true for internal
combustion
a.
Fuel burn inside the system boundary.
b.
Working fluid and fuel are mixed and burn
together.
c.
IC engine has minimum system temperature.
d.
In case of internal combustion, the cycle must
be open
11.
Which statement is NOT true for external
combustion
a.
Fuel burn outside the system boundary.
b.
Only 2 to 3% power plants in India have external
combustion system.
c.
Only heat transfer take place to the working
fluid.
d.
In case of closed cycle, the combustion must be
external.
12.
Natural gases are generally used in which power
plant
a.
Gas power plant
b.
Steam power plant
c.
Internal combustion engine
d.
None of above
13.
Minimum weight to power ratio is of
a.
Gas power plant
b.
Steam power plant
c.
Internal combustion engine
d.
None of above
14.
Pressure ratio is maximum in
a.
Gas power plant
b.
Steam power plant
c.
Internal combustion engine
d.
None of above
15.
What is the correct order of pollution created
by different power plants in increasing order?
a.
Gas power plant < Steam power plant < IC
engine
b.
Steam power plant < Gas power plant < IC
engine
c.
IC engine < Gas power plant < Steam power
plant
d.
Gas power plant < IC engine < Steam power
plant
16.
A 200 MW steam power plant use 110 ton/hr coal.
How much ash is it generate per hour (approximately)?
a.
10 ton
b.
25 ton
c.
35 ton
d.
55 ton
17.
Which type of ash is more difficult to handle?
a.
bottom ash
b.
fly ash
c.
ionized ash
d.
solid ash
18.
Which is ionized in ESP (Electrostatic
Precipretator)?
a.
air
b.
fly ash
c.
bottom ash
d.
electron
19.
Around how much power of power plant is consumed
by ESP?
a.
20-25%
b.
40%
c.
below than 20%
d.
more than 80%
20.
An electrostatic precipitator (ESP) is a
filtration device that removes fine particles, like dust and smoke, from a
flowing gas using the force of ___________ minimally impeding the flow of gases
through the unit.
a.
an induced electrostatic charge
b.
an induced electrostatic proton
c.
an induced current
d.
an ionized air
21.
Power
cycles are cycles which convert
a.
heat
input into mechanical work output
b.
mechanical
work input into heat output
c.
hydraulic
power input into mechanical work output
d.
hydraulic
input into heat output
22.
Which statement is NOT correct for Rankine cycle?
a.
The Rankine cycle is a model that is used to predict the
performance of steam turbine systems.
b.
The Rankine cycle is an idealized thermodynamic cycle of a heat engine that converts heat
into mechanical work.
c.
The heat is
supplied externally to a closed loop, which usually uses water as the working
fluid.
d. The Rankine
degree is defined as equal to one degree Celsius, rather than the one
degree Fahrenheit.
23.
Which statement is NOT correct?
a.
Heat pump cycles transfer heat from low to high
temperatures using mechanical work input.
b.
Cycles composed entirely of
quasistatic processes can operate as power or heat pump cycles by controlling the process direction.
c.
Gas power cycles are
thermodynamic cycles,
which use air, as the working fluid.
d.
As is typical in all conventional thermal power stations the heat is used to generate steam
which drives a steam condenser connected to an electric generator which
produces electricity.
24.
Which statement is NOT correct?
a.
In most of the places in the world the turbine
is steam-driven.
b.
Most power
stations in the world burn
fossil fuels such as coal, oil, and natural gas to generate electricity.
c.
Heat recovery steam generators (HRSGs) use the
heat rejected from other processes such as gas turbines.
d.
The purpose of a surface condenser is to condense the interred steam from a steam turbine to obtain maximum efficiency.
25.
How much land is required to setup a 1MW solar
power generation Unit (approximately)?
a.
4.5 to 7.5 acres
b.
2.5 to 4.5 acres
c.
1.5 to 2.5 acres
d.
0.2 to 1.5 acres
26.
What is the life-time of a typical Solar Power
plant?
a.
less than 10 years
b.
around 25 years
c.
more than 80 years
d.
cannot say
27.
What is the annual energy generated from a 1 MW
Solar Power plant?
a.
1.0 Million units
b.
1.5 Million units
c.
2.5 Million units
d.
3.5 Million units
28.
What is the NAS value of oil?
a.
1 for turbine oil servo-46
b.
3 for
turbine oil servo-46
c.
6 for turbine oil servo-46
d.
7 for turbine oil servo-46
29.
The diaphragm is used in steam turbine to
prevent
a.
leakage of lubricants
b.
leakage of steam
c.
leakage of water
d.
leakage of fuel
30.
The heat added in such a manner that the heat
received from the inner wall of the container and the droplets are individually
converted into steam bubbles. This is
the property of
a.
Nucleate boiling
b.
Film boiling
c.
Both
d.
None
31.
In which boiling process bubble film is created
at the inner surface of the container?
a.
Nucleate boiling
b.
Film boiling
c.
Both
d.
None
32.
The deviation of boiling process from nucleate
boiling to film boiling is known as
a.
arrival to film boiling (AFB).
b.
departure from nucleate boiling (DNB).
c.
transition between nucleate boiling and film
boiling (TNFB)
d.
none of above
33.
In which circulation the medium moves through a
mechanical pump?
a.
Natural circulation
b.
Assist circulation
c.
Forced circulation
d.
Once through system
34.
In which type of economizer only water flows
through the circuit?
a.
Steaming economizer
b.
Non-steaming economize
c.
Both
d.
None
35.
Which type of drought is used in maximum boiler
in which at the tip of the burner will be zero?
a.
Forced draft
b.
Induced drought
c.
Balance drought
d.
None of above
36.
Which is not true for critical boiler?
a.
works the pressure above the critical pressure
b.
works in the principle of once through system
c.
no drum
d.
no separator
37.
Higher value of HGI of coal means
a.
coal can be easily grinded
b.
coal cannot be easily grinded
c.
coal can be easily handle
d.
coal cannot be easily handle
38.
Which is not a factor affecting for a coal mill
performance?
a.
Grindability index of coal
b.
Mill component wear
c.
Fineness of coal
d.
carbon contain of coal
39.
Which is not an advantages of (PF) pulverized
coal fired boiler than the other boiler?
a.
the fire can be easily controlled.
b.
Cheaper low grade coal can be burnt easily.
c.
Pulverized coal burners act like petroleum.
d.
Flexibility in firing to meet fluctuating load.
40.
By using which type of soot blower erosion and corrosion
of tube can be avoided?
a.
Wall soot blower
b.
Rotary soot blower
c.
Sonic soot blower
d.
None of these
41.
Sudden change of load and maintaining of high
level of water may be caused of
a.
foaming of boiler
b.
priming of boiler
c.
cavitation of boiler
d.
critical heating of boiler
42.
Which is not an effect of soot deposits in a
boiler?
a.
reduce the heat transfer rate and increase flue
gas temperature.
b.
block the flue gas path which increases the
drought loss.
c.
may lead to erosion.
d.
damage the tube in dry ash conveying system.
43.
Which is not a method are used for steam
temperature control in boiler?
a.
Burner tilting method
b.
Attemporation control
c.
Elevation of fuel firing
d.
By providing excess steam
44.
What is over speed of turbine?
a.
speed > 110 % of rated speed
b.
speed > 120 % of rated speed
c.
speed > 125 % of rated speed
d.
speed > 115 % of rated speed
45.
Which is not a turbine tripping condition?
a.
Condenser vacuum very low
b.
Main steam pressure and temperature low and
high.
c.
Mot oil level high
d.
High differential expansion
46.
The slope of T-s diagram at constant pressure
depends on
a.
only temperature
b.
only specific volume
c.
only specific entropy
d.
only specific enthalpy
47.
Which component is not present in Open Brayton
Cycle?
a.
condenser
b.
turbine
c.
heat exchanger/combustion chamber
d.
intercooler
48.
Which is not true for air standard cycle?
a.
open and close cycles are same
b.
working substance is air throughout the cycle
c.
compression and expansion are isobaric
d.
Cv and Cp values remain
constant
49.
The work done by the turbine is written as
difference of enthalpy of inlet and outlet steam of turbine only if
a.
flow is steady
b.
turbine is perfectly insulated
c.
change in potential and kinetic energy are
neglected
d.
only when all above assumptions are valid
50.
The properties of gas uses in Brayton cycle at
different state is given below
Temperature
|
Specific Enthalpy
|
|
At the inlet of compressor
|
300 K
|
6000 kJ/kg
|
At the exit of compressor
|
400 K
|
10,000 kJ/kg
|
At the entry of turbine
|
1000 K
|
20,000 kJ/kg
|
At the exit of turbine
|
600 K
|
12,000 kJ/kg
|
correct efficiency of the cycle is
a.
50%
b.
40%
c.
80%
d.
none of these
51.
The efficiency of air standard Brayton Cycle
depends upon
a.
enthalpy of all four states
b.
temperature of all four states
c.
only the temperature of working fluid at
compressor inlet and outlet
d.
only the temperature of working fluid at turbine
inlet and outlet
52.
η
I II
which have greater value of ratio
of heat capacity at constant pressure to constant volume?
a.
I
b.
II
c.
both have same value of γ.
d.
cannot determine
53.
The approximate value of back work ratio in Brayton
cycle is
a.
30-40%
b.
40-50%
c.
50-60%
d.
more than 100%
54.
The approximate value of back work ratio in
Rankine cycle is
a.
30-40%
b.
40-50%
c.
50-60%
d.
1-2%
55.
Why domestic LPG cylinder is costly when liquid
petroleum gas is cheaper?
a.
high cost of cylinder material and its
construction
b.
high cost of leak proof joint
c.
high cost of compressed air
d.
high cost of transportation
56.
rw and rbw are work ratio
and back work ratio of a real power plant then what is the maximum value of (2√rw
+3√rbw) is
a.
2
b.
√13
c.
√15
d.
1
57.
A power plant working on Brayton Cycle, the
power supplied to the working fluid in combustion chamber is 6000 kW and heat
rejected to the air is 9000 kW. If net work done by the cycle is 2880 kW then
the efficiency of this cycle is
a.
40%
b.
33.33%
c.
32%
d.
50%
58.
The pump work is very less compare to compressor
work because
a.
pump convert mechanical energy to hydraulic
energy but compressor convert mechanical energy to kinetic energy.
b.
working pressure is very less in pump compare to
compressor.
c.
mass flow rate is very high in compressor compare
to pump.
d.
the density of air is very less than water.
59.
A fuel of calorific value 42 MJ/kg is burned in
a combustion chamber. The air (Cp = 1 kJ/kg-K) enter in the combustion
chamber with the temperature 420 K and the flue gasses (Cp = 1.5
kJ/kg-K) come out from combustion chamber with the temperature 840 K. If there
is loss of 10% in the combustion chamber then air fuel ration in combustion
chamber is
a.
55.05
b.
88
c.
50
d.
100
60.
Which efficiency is greater than one?
a.
isentropic efficiency of compressor
b.
isentropic efficiency of turbine
c.
efficiency of combustion chamber
d.
none of above
61.
Air enters to the compressor operating at the
pressure 1 bar and 27⁰ C and the pressure ratio is 4. The maximum temperature
in the cycle when back work ratio is 0.4
a.
445.79 K
b.
678.1 K
c.
114.5 K
d.
1114.5K
62.
T1, T2, T3 and
T4 are the temperature of working fluid in different stages in
Brayton Cycle. T1 and T2 are minimum and maximum temperature
of compressor respectively and same T3 and T4 are minimum
and maximum temperature of turbine respectively (note: these assumptions are following
in whole chapter if nothing is mention). If T2 and T4 is
equal and they are also equal to the minimum value of average of T1
and T3 then net maximum possible work is
a.
= 0
b.
)max = Cp(√T3
- √T1)2
c.
)max = Cp(T3
- T1)
d.
)max = Cp√(T3
2 - T1 2)
NOTE: All
other symbols have their general meaning in whole cheapter.
63.
A Brayton cycle has an efficiency equal to
carnot efficiency. Which statement is not true for this Brayton cycle
a.
pressure ration is maximum
b.
)max =
c.
)max =
d.
= 0
64.
a.
e.
f.
g.
1. d 2. b 3.
b 4. b 5. d 6. c 7.
d 8. d 9. d 10.
c 11. b 12. a
13. a 14. b 15.
d 16. c 17. b 18. a 19. a 20.
a 21. a 22. d 23. d 24. d
25. a 26.
b 27. b 28. c 29. b 30. a 31.
b 32. b 33. b 34. b 35.
c 36. d
37. b 38. d 39.
c 40. c 41. b 42. c 43. d
44. a 45. c 46. a 47. d 48. c
49. d 50. b 51.
c 52. a 53. b 54. d 55. c 56.
b 57. c 58. d 59. b 60. d
61. d 62. b 63.
c 64.
HINT
50.
calculate efficiency by using enthalpy.
56. Assume
work ratio as sin2
then back work ratio is automatically cos2θ.
57. Use
formula η =
.
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