Steam Turbines
1. Non Condensing steam turbine can
also be called as _________
a) Extraction steam turbine
b) Back pressure steam turbine
c) Impulse steam turbine
d) None of the mentioned
View Answer
Answer: b
Explanation: The other name for Non condensing turbines is back pressure
turbines.
2. Condensing turbine is used for
__________
a) central power generation
b) to reduce outlet temperature
c) to increase efficiency of steam
d) none of the mentioned
View Answer
Answer: a
Explanation: Reducing outlet temperatures and increasing efficiency of the
steam are required for every turbine irrespective of its use. So condensing
turbines are used for central power generation.
3. Steam turbine is classified on
basis of __________
a) type of blades
b) exhausting condition
c) type of Steam flow
d) all of the mentioned
View Answer
Answer: d
Explanation: Steam turbines are classified by
type of blades, exhausting condition, type of steam flow, division of steam
flow, type of compounding.
4. High pressure turbine is a
Non-Condensing turbine due to __________
a) exhaust conditions
b) axial flow of the steam
c) pressure-velocity compounding
d) velocity compounding
View Answer
Answer: a
Explanation: For high pressure turbines exhaust conditions are controlled by
regulating valve which makes them to come under the category of Non-Condensing
turbines.
5. Impulse blades are in the shape
of __________
a) Rain drop
b) Circular
c) Half moon
d) None of the mentioned
View Answer
Answer: c
Explanation: Blades used in impulse turbines are half moon shaped because as
steam enters the moving blade it pushes the blade forward.
6. Astern turbines are used in
_________
a) power generation
b) marine purposes
c) aircraft
d) none of the mentioned
View Answer
Answer: b
Explanation: Astern turbines are those classified based on exhaust conditions
and are used for marine purposes.
7. In condensing turbines vacuum is
obtained by ____________
a) sudden pressure drop
b) removal of non condensable gases
c) sudden drop in pressure and by removal of non condensable gases
d) none of the mentioned
View Answer
Answer: c
Explanation: Due to sudden drop in pressure vacuum appears and the remaining
non condensable gases are removed from the steam in order to maintain the
vacuum.
8. Cross compound steam turbines are
once used in _____________
a) generation of electricity
b) marine ships
c) automobiles
d) none of the mentioned
View Answer
Answer: b
Explanation: Cross compound turbines are once used in marine ships before two
stroke diesel engines.
9. When steam reaches turbine blades
the type of force responsible for moving turbine blades are _____________
a) Axial force
b) Shear force
c) Longitudinal force
d) None of the mentioned
View Answer
Answer: a
Explanation: Axial force pushes the turbine blade forward and causes movement
in turbine blade.
10.
Reaction
turbine works with the force obtained from change in pressure energy.
a) True
b) False
View Answer
Answer: a
Explanation: Reaction turbine runs with the force obtained from change in
pressure energy.
11.
Multi
spool gas turbines are operated at high pressure and high idle rpm.
a) True
b) False
View Answer
Answer: a
Explanation: Multi spool gas turbine has high pressure spool operating at high
idle rpm.
12.
Based on
type of flow arrangements gas turbines are classified into _____________
a) None of the mentioned
b) Impulse-reaction gas turbine
c) Open cycle gas turbine
d) Axial flow gas turbine
View Answer
Answer: d
Explanation: Based on the type of flow, Gas turbines are divided into two
types. They are axial flow gas turbines, radial flow gas turbines.
13.
Identify
the types of Gas turbines ___________
a) Turbo jet
b) Turboprop
c) Turbo fan
d) All of the mentioned
View Answer
Answer: d
Explanation: Gas turbines are further classified into Turbojet, Turboprop,
Turbofan, After burning Turbo jet.
14.
Gas
Turbine Engines, when compared to Reciprocating engines have ________
a) high power to weight ratio
b) low power to weight ratio
c) produce low power
d) none of the mentioned
View Answer
Answer: a
Explanation: High power to weight ratio is the basic reason behind using Gas
turbines in Air crafts thereby replacing reciprocating engines.
15.
For
producing Same power ____________
a) reciprocating engines will be smaller when compared to Gas turbine engines
b) gas turbine engines are smaller when compared to reciprocating engine
counter parts
c) reciprocating engines are complex
d) none of the mentioned
View Answer
Answer: b
Explanation: As for gas turbine Engine power to weight ratio is less when
compared to reciprocating engine.
16.
Most
preferable Gas turbines are required to be used in _____________
a) fluctuating loads
b) constant loads
c) idling conditions
d) none of the mentioned
View Answer
Answer: b
Explanation: Gas turbines are preferred to be used in constant load conditions
as Fluctuating loads require fluctuating power for which fuel is more consumed.
17.
Gas
turbines work on ________
a) Otto cycle
b) Dual cycle
c) Brayton cycle
d) Diesel cycle
View Answer
Answer: c
Explanation: Gas turbines works on brayton cycle.
18.
Amount of
fuel energy used by compressor is __________
a) half the total energy
b) two third of the total energy
c) one third of the total energy
d) none of the mentioned
View Answer
Answer: b
Explanation: Two thirds of the total energy produced from combustion of fuel is
used by compressor.
19.
Gas
turbine performance majorly depends on __________
a) compressor efficiency
b) calorific value of fuel used
c) nozzle efficiency
d) none of the mentioned
View Answer
Answer: a
Explanation: As two thirds of the total energy produced from combustion is used
by compressor, compressor efficiency plays a major role in determining Gas
turbine performance.
20.
Some of
the types of combustors available are ___________
a) annular
b) can Annular
c) silo
d) all of the mentioned
View Answer
Answer: d
Explanation: Types of Combustor are
Annular
Can Annular
Silo.
21.
Steam
turbines work on __________
a) Otto cycle
b) Dual cycle
c) Rankine cycle
d) None of the mentioned
View Answer
Answer: c
Explanation: Otto cycle petrol is used as fuel, Rankine cycle is the process
followed in steam turbines.
22.
Gas
turbines work on ___________
a) Rankine cycle
b) Diesel cycle
c) Brayton cycle
d) None of the mentioned
View Answer
Answer: c
Explanation: Rankine cycle is used in steam turbines. Brayton cycle is followed
in gas turbines.
23.
Generally,
water is used as working fluid in rankine cycle.
a) True
b) False
View Answer
Answer: a
Explanation: Rankine cycle is followed in steam turbines. In steam turbines
generally, water is used as working fluids.
24.
Ideal
Brayton cycle consists of ________
a) Isoentropic process and Isobaric process
b) Adiabatic process and Isobaric process
c) Adiabatic process
d) None of the mentioned
View Answer
Answer: a
Explanation: Ideal brayton cycle works on isoentropic process and isobaric
process.
25.
Actual
Brayton cycle works on _________
a) Isoentropic process and Isobaric process
b) Adiabatic process and Isobaric process
c) Isoentropic process
d) None of the mentioned
View Answer
Answer: b
Explanation: Actual brayton cycle works on Adiabatic process and Isobaric
process slight deviations from actual brayton cycle.
26.
Brayton
cycle is also known as __________
a) Joule cycle
b) Regenerative cycle
c) Carnot cycle
d) None of the mentioned.
View Answer
Answer: a
Explanation: Regenerative cycle is a closed loop usage of working fluid in
rankine cycle. Brayton cycle is also called a joule cycle.
27.
Brayton
cycle is also called an Ericsson cycle.
a) True
b) False
View Answer
Answer: a
Explanation: Brayton cycle is also called an ericsson cycle.
28.
Brayton
cycles are further divided into ______ types.
a) 2
b) 3
c) 4
d) None of the mentioned
View Answer
Answer: a
Explanation: Brayton cycle is further divided into two types. They are open
cycle and closed cycle.
29.
Internal
combustion chamber is used in _______ Brayton cycle.
a) open
b) closed
c) depends
d) none
View Answer
Answer: a
Explanation: Internal combustion chambers are present in open cycles to heat
the working fluid.
30.
Heat
exchanger is used in a closed Brayton cycle.
a) True
b) False
View Answer
Answer: a
Explanation: Heat exchangers are used in closed cycles to raise the temperature
of working fluid.
31.
Carnot
engine follows ____________
a) Isothermal process
b) Isoentropic process
c) Isothermal and Isoentropic process
d) None of the mentioned
View Answer
Answer: c
Explanation: Carnot cycle process follows 4 process. They are
Isothermal heat addition
Reversible adiabatic expansion
Reversible isothermal compression
Reversible adiabatic heat rejection.
32.
Clausius
inequality is applied at _____________
a) reversible isothermal heat addition
b) reversible adiabatic expansion
c) reversible isothermal compression
d) reversible isothermal heat rejection
View Answer
Answer: c
Explanation: In reversible adiabatic compression entropy is same as from
reversible isothermal heat addition and this can be found out by clausius
inequality.
33.
During
reversible adiabatic explansion and compression entropy doesnot change.
a) True
b) False
View Answer
Answer: a
Explanation: Adiabatic process mean there is no heat transfer and if there is
no heat transfer entropy doesnot change.
34.
What
happens if all the process in carnot cycle be reversed?
a) Works as heat engine
b) PMM1 occurs
c) Works as refrigerator
d) PMM2 occurs
View Answer
Answer: c
Explanation: When all the process in carnot cycle be reversed heat is absorbed
from the body and reduces the temperature of the body which means a
refrigerator. When carnot cycle is not reversed it acts as a heat engine.
35.
Working
fluid of rankine cycle usually _____________
a) Water
b) Methane
c) Hard water
d) None of the mentioned
View Answer
Answer: a
Explanation: Water is used as working fluid in rankine cycle.
36.
Steam
turbines work on __________
a) Rankine cycle
b) Carnot cycle
c) Dual cycle
d) None of the mentioned
View Answer
Answer: a
Explanation: Rankine cycle is generally used where heat energy is to be
converted in mechanical energy.
37.
In non
ideal rankine cycle the compression of pump and expansion of turbine is
isoentropic.
a) True
b) False
View Answer
Answer: b
Explanation: In general isoentropic cases are harder to occur and hence in
rankine cycle they doesnot exist as isoentropic process.
38.
What is
the use of reheat cycle in steam turbines?
a) To remove the moisture from the steam
b) To increase the steam temperature
c) To increase steam pressure
d) None of the mentioned
View Answer
Answer: a
Explanation: Reheat cycle is worked with rankine cycle to remove the moisture
from the steam.
39.
In
rankine cycle with reheat how mny turbines work?
a) 1
b) 2
c) 3
d) 4
View Answer
Answer: b
Explanation: One turbine is to produce work and the other turbine is to reheat.
40.
Reheat
temperatures are very close to ______ temperature.
a) inlet
b) outlet
c) intermediate
d) none of the mentioned
View Answer
Answer: a
Explanation: After passing from the first turbine again the steam enters the
boiler to raise their temperature close to the inlet temperature and then
enters the low pressure turbine.
41.
The cycle
of evaporation and rain in nature can be assumed to be a kind of Carnot cycle.
If ocean water instead of evaporation are boiled by the heat of Sun at a
constant temperature of 100 deg C and the condensation of steam into water
droplets within the clouds occur at constant temperature of -20 deg C. Find the
thermal efficiency of Carnot cycle of nature?
a) 0.2777
b) 0.3030
c) 0.3333
d) 0.50
View Answer
Answer: b
Explanation: Carnot thermal efficiency = 1-(Mean temperature of heat
addition)/( Mean temperature of heat rejection).
42.
How is it
advantageous to expand steam at 250 deg C in a turbine as compared to expanding
saturated steam in similar turbine?
a) Enhances the thermal efficiency of the cycle
b) Reduces the mechanical damage caused to turbine blades due to wet steam
c) Increases the mean temperature of heat addition
d) All of the mentioned
View Answer
Answer: d
Explanation: Superheating steam makes expansion within turbine to take place in
dry region to a greater extent.
43.
In a
steam turbine power plant, the boiler feedwater temperature is marked as 30 deg
C, ocean as sink with temperature 20 deg C and desired thermal efficiency of
the plant is 0.46. Find the temperature of steam entering the turbine?
a) 500degC
b) 505.55degC
c) 507.62degC
d) 509.18degC
View Answer
Answer: d
Explanation: Mean temperature of heat addition = (Temperature of feedwater +
Temperature of steam entering turbine)/2.
44.
In a
newly developed innovative idea brought up by CSIR in India, gas turbine
exhaust gas are being utilized to convert feedwater into steam. Certain data of
the experiment are as follows: mass flow rate of exhaust gas = 40 kg/hr,
enthalpy of exhaust gas at the time of their exit from gas turbine is 600
kJ/kg, steam turbine output as measured by brake dynamometer = 60 hp-sec,
thermal efficiency of steam power plant is 0.25, efficiency of exhaust gas in
converting feedwater into steam is taken as 50%. Find the enthalpy of exhaust
gas remaining after they generate steam from feedwater?
a) 350.0KJ/Kg
b) 241.2KJ/Kg
c) 112.45KJ/Kg
d) 512.56KJ/Kg
View Answer
Answer: b
Explanation: Heat added = difference of enthalpies * efficiency of exhaust gas
in converting feedwater into steam and then apply thermal efficiency formula
for Carnot efficiency.
45.
Why does
Carnot cycle has maximum efficiency?
a) Since all the processes in Carnot cycle are completely reversible
b) Since only process of expansion and compression are reversible
c) Since only the process of heat addition and heat rejection are reversible
d) Since all processes involved are irreversible
View Answer
Answer: a
Explanation: All the processes in Carnot cycle are completely reversible.
46.
A
researcher during an experiment found that mean temperature of heat addition
and heat rejection for a steam power plant operating on a Carnot cycle is 127
deg C and 27 deg C respectively. Later, he calculated the thermal efficiency of
the steam cycle. Can you predict what was it?
a) 0.20
b) 0.25
c) 0.30
d) 0.35
View Answer
Answer: b
Explanation: Thermal efficiency of a Carnot cycle is given by (Mean temperature
of heat addition-Mean temperature of heat rejection)/(Mean temperature of heat
addition).
47.
If Carnot
cycle has maximum possible thermal efficiency, then why don’t the steam turbine
power plants run on Carnot cycle?
a) Because the process of heat addition is at constant temperature
b) As mean temperature of heat addition is quite low in case of Carnot cycle
c) Since work consumed by compressor is approximately equal to work produced by
turbine
d) Because boiler can’t be maintained at constant pressure in Carnot cycle
View Answer
Answer: c
Explanation: As compressor and turbine both work on wet steam, therefore they
don’t have significant difference in their work.
48.
The mass
of coal(lignite) used in boiler of a steam power plant is 20 ton per hour and
calorific value of lignite is 13600 KJ/kg. Also, if the entropy of steam
entering turbine is 750 J/K and that of feedwater entering the boiler is
550J/K. Find the mean temperature of heat addition?
a) 100 deg C
b) 115 deg C
c) 110 deg C
d) 105 deg C
View Answer
Answer: d
Explanation: Tmean = Q/(change in entropy).
49.
In a
solar operated steam power plant, water is converted into steam via solar heat.
If the effective area of solar plate is 200m2, value of solar constant
is 1.362KW per m2, efficiency of solar components is 17% and overall
thermal efficiency of steam cycle desired is 12%. Find the turbine power
output?
a) 45KW
b) 22.46KW
c) 5.55KW
d) 16.54KW
View Answer
Answer: c
Explanation: Efficiency of steam cycle = (Turbine power output/(solar
constant*area*solar efficiency)).
50.
A boiler
feed pump is used to raise ___________
a) Static pressure of feedwater
b) Dynamic pressure of feedwater
c) Static & Dynamic pressure of feedwater
d) None of the mentioned
View Answer
Answer: a
Explanation: Since water needs to be brought to boiler pressure and is not in
motion
51.
When
boiler pressure is increased efficiency is ____________
a) decreased
b) increased
c) remains constant
d) none of the mentioned
View Answer
Answer: b
Explanation: When boiler pressure is increased efficiency is increased.
52.
Why is
operating pressure of boiler designed?
a) To maintain economic equivalence
b) For not decreasing efficiency
c) No such operating pressures are designed
d) None of the mentioned
View Answer
Answer: a
Explanation: If boiler pressure is increased efficiency also increases. But if
we keep on increasing boiler pressure to increase efficiency, Boilers that work
under high pressure as costly and so boiler operating pressures are designed so
that for a particular boiler it does not work beyond that pressure and it
maintains economical equivalence.
53.
When
boiler pressure is increased __________
a) efficiency is increased
b) Qh is increased
c) efficiency & Qh is increased
d) none of the mentioned
View Answer
Answer: c
Explanation: When boiler pressure is increased Qh increases as a result
efficiency is increased.
54.
Can we
keep on increasing the pressure of the boiler to increase its efficiency?
a) Yes
b) No
View Answer
Answer: b
Explanation: Boilers that work under high pressure are much more costly.
55.
What
happens to the efficiency when temperature is increased in rankine cycle?
a) Increased
b) Decreased
c) Remains constant
d) None of the mentioned
View Answer
Answer: a
Explanation: When the temperature is increased reheating capacity of the steam
increases and thus efficiency also increases.
56.
Increase
in temperature increases __________
a) reheating capacity of the fluid
b) thermal efficiency
c) reheating capacity of the fluid & thermal efficiency
d) none of the mentioned
View Answer
Answer: c
Explanation: When reheating capacity is increased it automatically increases
the thermal efficiency.
57.
When
condenser pressure is lowered efficiency _________
a) increases
b) decreases
c) does not effect
d) none of the mentioned
View Answer
Answer: a
Explanation: When operating pressure of condenser is lowered, Heat rejecting
temperature also lowers which eventually increases the efficiency.
58.
Superheating
the steam increases efficiency.
a) True
b) False
View Answer
Answer: a
Explanation: Average Temperature of steam can be increased without increasing
the pressure by superheating.
59.
Superheating
the steam results in __________
a) increasing the efficiency
b) decreases the moisture content
c) increasing efficiency & decreases the moisture content
d) none of the mentioned
View Answer
Answer: c
Explanation: Superheating the steam increases the steam temperature and also
decreases the moisture content in the steam.
60.
When
boiler pressure is increased __________
a) temperature also increased
b) efficiency also increases
c) temperature & efficiency increases
d) none of the mentioned
View Answer
Answer: a
Explanation: When boiler pressure is increased steam temperature increases
which increases efficiency.
61.
What does
thermodynamic efficiency of steam turbine mean?
a) Ratio of power developed to the power that can be developed by ideal turbine
b) Ratio of power that can be developed by ideal turbine to the power developed
by the actual turbine
c) Ratio of inlet temperature to outlet temperature
d) None of the mentioned
View Answer
Answer: a
Explanation: Thermodynamic efficiency is the ratio of power developed by actual
turbine to the power that can be developed by ideal turbine.
62.
What does
aerodynamic efficiency mean?
a) Energy that can be extracted from a given volume of steam at given
temperature and pressure
b) Amount of steam turbine blade can allow to flow inside
c) Amount of energy contained in steam
d) None of the mentioned
View Answer
Answer: a
Explanation: Aerodynamic efficiency means energy that can be extracted from
given volume of steam at given pressure and temperature.
63.
If
efficiency of boiler increases then efficiency of steam turbine ______
a) decreases
b) increases
c) cannot be determined
d) none of the mentioned
View Answer
Answer: b
Explanation: If the efficiency of steam boiler increases temperature also
increases which indirectly increases its efficiency.
64.
If
condenser efficiency increases then overall efficiency of steam turbine _______
a) decreases
b) increases
c) remains constant
d) none of the mentioned
View Answer
Answer: b
Explanation: If condenser efficiency increases it raises the steam temperature
and hereby increasing overall efficiency.
65.
What does
combustion efficiency mean?
a) Boiler ability to burn the fuel to fuel that is not burned and amount of air
present at exit
b) Calorific value that can be obtained by burning a fuel
c) Energy that is released when fuel is burned
d) None of the mentioned
View Answer
Answer: a
Explanation: Combustion efficiency is used to denote the amount of fuel burned
by using the air.
66.
What does
fluid to fuel efficiency mean?
a) It indicates the overall efficiency of the boiler
b) Indicates fuel efficiency
c) Overall efficiency excluding boiler efficiency
d) None of the mentioned
View Answer
Answer: a
Explanation: Fluid to fuel efficiency indicates overall efficiency including
Boiler efficiency, conduction, convection and radiation, etc.
67.
The total
energy in the fuel is called as _____________
a) boiler efficiency
b) boiler energy
c) gross calorific value
d) none of the mentioned
View Answer
Answer: c
Explanation: Gross calorific value indicates the total energy a fuel can
release when burned.
68.
Flue
gases _______ efficiency.
a) decreases
b) increases
c) does not effect
d) none of the mentioned
View Answer
Answer: b
Explanation: Flue gases effect combustion of the fuels and due to that it
affects the overall efficiency.
69.
Nozzle
efficiency can be defined by __________
a) ratio of kinetic energy of the steam leaving the nozzle to the potential
energy available with the steam while entering
b) pressure of the steam leaving the nozzle to pressure of the steam entering
the nozzle
c) temperature of the steam leaving the nozzle to the temperature of the steam
entering the nozzle
d) none of the mentioned
View Answer
Answer: a
Explanation: Nozzle is used to convert the potential energy of the steam
available into kinetic energy to run the turbine.
70.
What is
the typical efficiency of the nozzle?
a) 0.45-0.56
b) 0.9-0.99
c) 0.5-0.7
d) 0.67-0.86
View Answer
Answer: b
Explanation: The typical efficiency of the nozzle is between 0.9 and 0.99.
71.
Heat rate
is used to define the efficiency of steam power plant.
a) True
b) False
View Answer
Answer: a
Explanation: Heat rate = (Input energy)/(output power).
72.
Inverse
of efficiency is called as ____________
a) steam rate
b) heat rate
c) heat utilized
d) none of the mentioned
View Answer
Answer: b
Explanation: From the formula, we can identify heat rate is the inverse of
steam rate.
73.
To
increase plant efficiency heat rate is to be _________
a) increased
b) decreased
c) no relation with the heat rate
d) none of the mentioned
View Answer
Answer: b
Explanation: As heat rate is inverse of plant efficiency, to increase plant
efficiency heat rate is to be decreased.
74.
What are
the units of heat rate?
a) Kw/hr
b) No units
c) BTU/KWh
d) None of the mentioned
View Answer
Answer: c
Explanation: Chemical energy input units are BTU and electrical energy output
units are KWh. So units of heat rate are BTU/KWh.
75.
Chemical
energy of the fuel can be calculated by _________
a) Chemical energy of fuel = (Total fuel used) * (Higher heating value)
b) Chemical energy of fuel = (Calorific value) * (Fuel required for 1 Kcal of
energy)
c) Cannot be determined theoretically
d) None of the mentioned
View Answer
Answer: a
Explanation: Chemical energy of fuel = (Total fuel used) * (Higher heating
value).
76.
Heat rate
losses that can be directly effected by actions of operators is called ______
a) uncontrollable losses
b) controllable losses
c) non-Value added losses
d) none of the mentioned
View Answer
Answer: b
Explanation: Heat rate losses than be directly effected by actions of operator
are called controllable losses.
77.
Heat rate
deviation can be defined as _______
a) difference between actual and target heat rate
b) difference between heat rates at maximum and minimum temperatures
c) difference between calorific value of ideal fuel and actual fuel used
d) none of the mentioned
View Answer
Answer: a
Explanation: Heat rate deviation can be defined as the difference between the
actual and target heat rates.
78.
Steam
flow rate can be calculated by _______
a) 3600/p
b) 3600 He/p
c) 3600 P/He
d) None of the mentioned
View Answer
Answer: c
Explanation: Steam flow rate can be calculated by Ms = 3600 p/He.
79.
The rate
at which boiler in steam turbine produces steam is called __________
a) Steam rate
b) Steaming rate
c) Heat rate
d) None of the mentioned
View Answer
Answer: b
Explanation: The rate at which the boiler produces steam is called steaming
rate.
80.
Heat rate
can be used to find annual fuel costs.
a) True
b) False
View Answer
Answer: a
Explanation: Annual Fuel cost = Heat rate deviation * Fuel capacity * Capacity
factor * (Gross capacity * Auxiliary loads) * Time.
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