1. Pankaj watches a jet in air with
a long trail of exhaust gas at its rear. What type of engine do they run on?
a) Prop Jet
b) Back Pressure Gas Turbine
c) Jet Propulsion Gas Turbine
d) Steam turbine
View Answer
Answer: d
Explanation: Jet propulsion turbine provides high velocity and comfortable
flight at very high altitudes.
2. Arrange the words to make a
meaningful order: diffuser/exhaust cone/combustor/low pressure
compressor/turbine/intercooler/high pressure compressor.
a) low pressure compressor/ turbine/ intercooler/ diffuser/ combustor/ high
pressure compressor/ exhaust cone
b) diffuser/ low pressure compressor/ intercooler/ high pressure compressor/
combustor/ turbine/ exhaust cone
c) diffuser/ high pressure compressor/ intercooler/ low pressure compressor/
combustor/ turbine/ exhaust cone
d) combustor/ low pressure compressor/ turbine/ intercooler/ exhaust cone/ high
pressure compressor/ diffuser
View Answer
Answer: c
Explanation: Sequence of components in a Gas Turbine power plant.
3. Oil refineries seek significant
application of gas turbine in which form?
a) They utilize waste hot gas from Houdry Cracking Process in order to drive a
compressor
b) For peak load application
c) For standby application
d) For locomotive application
View Answer
Answer: a
Explanation: The waste gas from the process have enough energy to operate a gas
turbine which is used to drive a compressor supplying compressed air for the
houdry process.
4. Indian Railways has 2000 HP coal
burning units(locomotive wagon) with their efficiency as 20%. Calorific value
of coal is 30,000 KJ/Kg. Find mass of coal required per hp-sec?
a) 0.2486kg/s
b) 0.1110kg/s
c) 0.3568kg/s
d) 0.2254kg/s
View Answer
Answer: a
Explanation: Efficiency = work/heat supplied. Work is 2000 hp and heat supplied
is mass flow rate * calorific value.
5. Engineers design a Gas Turbine
Power Plant. Since the plant initial cost is too high, therefore engineers
think to remove the regenerator from their original design. Then, the immediate
consequence of the same would be?
a) Compressor work will increase
b) Combustor will require more fuel
c) Turbine will produce more work output per unit of fuel
d) Requirement of Intercooler to compensate for its loss
View Answer
Answer: b
Explanation: Regenerators act as heat exchangers that heat the air before it
enters the combustion chambers through exhaust gas emitting from exhaust cone.
6. Near a natural gas deposits, we
require to set up a gas turbine plant. Geologist inform engineers that helium
gas is found in abundance here. Hence, engineers seek to use helium as working
medium for the gas power plant. This turbine is a _________
a) Multi-shaft open cycle gas turbine
b) Single shaft open cycle gas turbine
c) Closed cycle gas turbine
d) Simple Open cycle Gas Turbine
View Answer
Answer: c
Explanation: Since the working fluid is other than air, therefore the plant is
closed cycle gas turbine.
7. In order to generate energy in
Sahara Desert where water is available in significantly low amount. Which
system can we employ in such a place?
a) Steam Turbine
b) Gas Turbine
c) Steam Engine
d) Tidal Engine
View Answer
Answer: b
Explanation: As gas turbine require very little or no water at all for their
functioning.
8. Fresh air at 14.7psi enters a
compressor of a gas turbine and is compressed isentropically. The gas at the
mouth of turbine is at 60 psi pressure and with a specific volume as 50 m3/kg.
What would be the specific volume of fresh air?
a) 136.54m3/kg
b) 125.64m3/kg
c) 126.54m3/kg
d) 135.64m3/kg
View Answer
Answer: a
Explanation: PVk=constant for isentropic process.
9. Assertion: Twin shaft arrangement
of gas turbine must consist of two shafts whether in series or parallel.
Reason: In multi shaft arrangement two or more turbine-compressor combinations
are carried on independent shafts. Select the most appropriate options
following.
a) Both assertion and reason are correct and reason precisely explains the
assertion
b) Both assertion and reason are correct but reason doesn’t exactly explains
the assertion
c) Assertion is correct whilst reason is incorrect
d) Assertion is incorrect whilst reason is correct
View Answer
Answer: d
Explanation: Single shaft arrangement must have all compressors and turbines to
be coupled in a series arrangement.
10.
The
presence of high temperature conditions often limit the use of materials in the
plant. Can you predict which of the options would be most suitable material for
the gas turbine components?
a) Mn-Ni Alloy
b) Ti-Al-Sn-Zr Alloy
c) Stainless steel
d) Cast Iron
View Answer
Answer: b
Explanation: Titanium has best high temperature resistance and is almost
unreactive even at elevated temperatures.
11.
How many
burners are placed in can-annular combustors in gas turbines?
a) 1
b) 3
c) 5
d) Not specific one or more
View Answer
Answer: d
Explanation: Multiple or single burners are evenly spaced in the combustor.
12.
Silo
combustors are mounted Internal to gas turbine body.
a) True
b) False
View Answer
Answer: b
Explanation: Silo combustors are mounted external to the gas turbines.
13.
Axial
flow turbines are used in ________
a) industrial gas turbines
b) air crafts
c) hybrid vehicles
d) none of the mentioned
View Answer
Answer: a
Explanation: Axial flow gas turbines are mostly used for industrial purposes.
14.
What
completes a stage in Turbine expansion?
a) One cycle passing through compressor
b) Row of moving blades followed by a row of stationary blades
c) Stationary blades row followed by Moving blades row
d) None of the mentioned
View Answer
Answer: c
Explanation: Turbine expansion takes place in stages. One stage comprises of a
Row of stationary blades followed by a row of moving blades.
15.
What does
TRIT in a gas turbine stand for?
a) Turbine Rotor Inlet Temperature
b) Total Raise at Inlet Temperature
c) Temperature Raise In Turbine
d) None of the mentioned
View Answer
Answer: a
Explanation: TRIT stands for Turbine Rotor Inlet Temperature and TIT stands for
Turbine Inlet Temperature.
16.
When at
idle conditions Gas Turbine Engines use more fuel when compared to
Reciprocating engines.
a) True
b) False
View Answer
Answer: a
Explanation: Though the conditions may be idle but to run the turbine
compressor to work, compressor takes as much as the two thirds of the total
power produced from combustion and remaining one third is used for power
output. So during Idle conditions power output may not be required but
compressor uses its 2/3 of energy, whereas reciprocating engines doesn’t
require any compressors equipped separately and hence less fuel will be burnt
during idle time when compared to Gas turbines.
17.
In Gas
Turbines Compressors raise the pressure of air by _______ times.
a) 25
b) 15
c) 30
d) 10
View Answer
Answer: c
Explanation: Compressor work is to raise the pressure of the air at constant
volume. In gas turbines, it raises by a factor of 30.
18.
In Gas
Turbines, Turbine is used to convert _________
a) Kinetic energy to Rotational energy
b) Potential energy of the gases to Rotational energy
c) Heat energy of the gases to Rotational energy
d) None of the mentioned
View Answer
Answer: a
Explanation: Highly pressurized gas from compressor burns the fuel injected
into combustor and those hot gases released move with high velocity towards
turbine which rotates the turbine.
19.
Hallow
perforated piece of heavy metal inside the combustor is called as _________
a) Fuel injector
b) Frame holder
c) Burner
d) None of the mentioned
View Answer
Answer: b
Explanation: As gas with high pressure enters the combustor with high
velocities, for continuous combustion, the combustor in such situations require
the frame to be held and therefore frame holder is used.
20.
Turbine
and Output shaft rotate freely without any connection to the engine.
a) True
b) False
View Answer
Answer: a
Explanation: Turbine and output shaft are completely stand alone in gas
turbine.
21.
Turbojet
is a combination of gas turbine with a propeller engine.
a) True
b) False
View Answer
Answer: a
Explanation: Turbojet is an air breathing jet engine which was used in
aeroplane. Both gas turbine and propeller together is a turbojet.
22.
A
compressor in the gas turbine is driven by the Turbine.
a) True
b) False
View Answer
Answer: a
Explanation: In a gas turbine both the turbine and compressor are connected to
each other where turbine itself drives the compressor eventually.
23.
What is
bypass ratio in Turbofan?
a) None of the mentioned
b) (Mass of the air passing through the engine)/(Mass of the air bypassing the
engine)
c) (Air entering the engine)/(Air leaving the engine)
d) (Mass of the air bypassing the engine)/(Mass of the air passing through the
engine)
View Answer
Answer: d
Explanation: The term bypass ratio is used in turbofan.In turbofan some of the
air enters the engine bypass and rotates the fan while the remaining air
rotates the turbine where these two fan and turbine provides the drag force
required.Bypass ratio is the ratio of air bypassing the engine to the ratio of
air passing through the engine.
24.
Turbojet
emits ______ engine noise when compared to Turbofan.
a) more
b) less
c) equal
d) none
View Answer
Answer: a
Explanation: Engine’s noise is directly proportional to the air coming from the
engine exhaust.In turbojet more air comes from the engine exhaust which is the
reason for more noise.
25.
Turboprop
engines are used in ________ aircrafts.
a) medium
b) large
c) small
d) none
View Answer
Answer: c
Explanation: As the air leaving the engine in turboprop is not sufficient to
produce required thrust, turboprop engines are used in conditions where less
rpms are required.
26.
In
turboprop engines ____ torque ____ rpm produced from the engine is converted
into high rpm low torque.
a) high, low
b) low, high
c) high, high
d) none
View Answer
Answer: b
Explanation: Turboprop engines generally have low torque and high rpms. In such
conditions, a reduction gear is used to convert it into low rpm and high torque
so that sufficient drag force can be provided.
27.
When
turboprop and turbofan operate at same speeds, turboprop consumes ________
fuel.
a) more
b) less
c) equal
d) none
View Answer
Answer: a
Explanation: Turbofan produces high rpm, low torque but reduction gear is used
to convert it into less rpm and high torque to provide required drag force, but
turbo fan operates at high rpms, So for turboprop to operate at same speed as
of turbofan they require more fuel when compared to turbofan.
28.
In
turboprop exhaust fan produces ___________
a) more than 25% of the total thrust
b) more than 40% of the total thrust
c) less than 25% of the total thrust
d) less than 10% of the total thrust
View Answer
Answer: d
Explanation: Due to additional expansion in the turbine system, Energy in the
thrust jet is lesser than 10% of the total energy produced by turboprop.
29.
Turboprops
are not generally operated in high speeds because of ________
a) while speed of the engine increases it looses it efficiency
b) turboprops are not able to produce high speeds
c) turboprops produce high torques
d) none of the mentioned
View Answer
Answer: a
Explanation: Turboprops cannot be operated at high speeds. Turboprops are
operated in between 0.6 and 0.7. When they are operated more than the mentioned
speeds they loose their efficiency.
30.
A closed
cycle gas turbine follows ________
a) Dual Cycle
b) Brayton Cycle
c) Stirling cycle
d) Carnot cycle
View Answer
Answer: b
Explanation: Closed cycle Gas turbines follow the Brayton cycle.
31.
This
turbine receives steam at high pressure of 600 to 900 psi and discharges it at
pressure suitable for supplying to existing low pressure plant. Identify the
turbine?
a) Topping Turbine
b) Back-Pressure Turbine
c) Condensing Turbine
d) Extraction Turbine
View Answer
Answer: a
Explanation: Topping turbine are specially designed turbine for this
application in industry.
32.
Arjun
underwent industrial training in his 2nd year at National Thermal Power Plant.
But he was surprised to know that a special turbine is used to meet the
electrical energy requirement in the plant itself. Can you identify which
turbine did he observe?
a) High Pressure Condensing Turbine
b) House Turbine
c) Gas Turbine
d) Mixed Pressure Turbine
View Answer
Answer: b
Explanation: Exhaust or extraction steam may be used for feedwater heater.
33.
Tanuj and
Shyam have a strong discussion over the advantages of Induction-Extraction
turbine.
Tanuj: They are employed when a particular manufacturing process require a
large quantity of steam at a particular pressure.
Shyam: They are employed when an abundance of waste steam is available at the
same pressure. Which one the two you think is correct?
a) Tanuj
b) Shyam
c) Tanuj & Shyam
d) None of the mentioned
View Answer
Answer: c
Explanation: They are used in both situations.
34.
Where in
industries do we find back-pressure turbines?
a) At a point in industry where waste steam has to be employed
b) When pressure needs to be applied at rear end
c) When one turbine bolster other
d) There is a requirement of process steam at single pressure
View Answer
Answer: d
Explanation: These discharge steam into a pressurized piping system to be used
for process heating.
35.
This
turbine is an ingenious method for accomplishing multi velocity staging in a
single wheel. Name this turbine?
a) Tangential Turbine
b) Single Stage Impulse Turbine
c) Multi Stage Impulse Turbine
d) None of the mentioned
View Answer
Answer: a
Explanation: They have reversing chamber equipped with stationary blades which
reverses the direction of the steam leaving the moving blades.
36.
A marine
officer asks you to design a turbine for marine propulsion. Which of the below
would be your best choice?
a) Mixed pressure turbine
b) Condensing high pressure regenerative turbine
c) Gas Turbine
d) Tandem-Compound double flow turbine
View Answer
Answer: b
Explanation: Due to high pressure generated by them.
37.
A
multipass turbine is a prime mover.
a) True
b) False
View Answer
Answer: a
Explanation: Prime mover includes every engine that can convert the chemical
energy of fuel into useful work.
38.
In Europe
special types of turbines are used that do not have fixed blades so that
pressure drop are necessary in all blade passages. Which turbine is it?
a) Tangential Turbine
b) Axial Flow Turbine
c) Radial Turbine
d) None of the mentioned above
View Answer
Answer: c
Explanation: They have blades rotating in the opposite direction with two
concentric shafts and two generators.
39.
You own
an industry in which the boiler generates a lot of waste steam which you think
could be utilized. Which turbine will you utilize?
a) Mixed Pressure Turbine
b) Back Pressure Turbine
c) Twin-Shaft Gas Turbine
d) Induction-Extraction Turbine
View Answer
Answer: d
Explanation: They have the capability to admit steam at a given pressure when
available.
40.
Mac
doubts that why do we use House Turbine in National Thermal Power Plants. Can
you clear his doubts?
a) The exhaust steam or extraction steam is used for feedwater heating or to
supply steam for small turbines serving as auxiliary drives
b) Have huge capacity sufficient enough to run the plant
c) Have minimum losses
d) They can be vertical compounded
View Answer
Answer: a
Explanation: Their ability to heat feedwater using extraction or exhaust steam.
41.
Gas and
Steam turbine combined power plant produces more electricity than traditional
power plants by how much percent?
a) 25
b) 40
c) 50
d) The given statement was false
View Answer
Answer: c
Explanation: When steam and gas turbines are jointly used in power plants and
the power produced by gas and steam turbines is used in producing electricity.
42.
Marine
compound power plants are also the combined gas and steam power plants.
a) True
b) False
View Answer
Answer: a
Explanation: Combined gas and steam power plants is the name given to marine
power plants.
43.
Maximum
supplementary firing means _________
a) minimum fuel that can be fired
b) maximum fuel that can fired with the oxygen available in turbine
c) maximum fuel that can be fired in given time
d) none of the mentioned
View Answer
Answer: b
Explanation: Maximum supplementary firing means maximum fuel that can be fired
with the oxygen available.
44.
Due to
the limits, upper efficiency of steam turbines is fixed to _________
a) 10-15%
b) 25-45%
c) 20-40%
d) 35-45%
View Answer
Answer: d
Explanation: In steam and gas turbine combined power plants, steam turbines
water is used as working medium. High pressure and high temperatures are
required for these high pressures which in turn requires high strengths so
expensive alloys like nickel and cobalt are used. These limit the upper
efficiency to 35-45%.
45.
How many
sections does waste heat recovery boiler have in steam generators?
a) 1
b) 2
c) 3
d) 4
View Answer
Answer: c
Explanation: In steam generators waste heat recovery boilers have 3 sections.
They are
Economiser
Evaporator
Superheater.
46.
Turbines
that are run by exhaust gases are called _______
a) power recovery turbines
b) stepped turbines
c) turbo compounded engine
d) none of the mentioned
View Answer
Answer: a
Explanation: Turbines that are run by exhaust gases are called power recovery
turbines.
47.
Combination
of two or more thermodynamic processes gives _________
a) decrease in efficiency
b) increase in efficiency
c) increases the temperature at exhaust
d) none of the mentioned
View Answer
Answer: b
Explanation: When two or more thermodynamic cycles work together their overall
combined efficiency increases by 50-60%.
48.
By using
combined cycle steam and gas power plant _________
a) specific fuel consumption can be decreased
b) efficiency increased
c) specific fuel consumption can be decreased and efficiency increased
d) none of the mentioned
View Answer
Answer: c
Explanation: If specific fuel consumption is decreased it indirectly increases
efficiency.
49.
What are
turbo-compound engines?
a) Turbines run at exhausts of Otto and diesel cycles
b) Combination of turbofan and turbojet engines
c) Combination of turboprop and turbofan engines
d) None of the mentioned
View Answer
Answer: a
Explanation: Turbo compound engines are used in air-crafts where turbines run
at exhausts of Otto and diesel cycles.
50.
High
power density is the advantage obtained from _______
a) solar Gas turbines
b) steam Turbines
c) cryogenic Gas turbines
d) none of the mentioned
View Answer
Answer: a
Explanation: Gas turbines have higher power density than steam turbines and in
the case of cryogenic gas turbines those could not be operated on solar power.
51.
High
power to weight ratio is the advantage of _______
a) Turboprop
b) Turbofan
c) Turbojet
d) All of the mentioned
View Answer
Answer: d
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