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15. Gas turbine engine - Q&A

64 questions found

Module 15. Gas turbine engine

If a burner was down, in a multi-can system, the engine would tend to

  • hang up.
  • run up.
  • surge.
Diverdeep asking:

explain??

Module 15. Gas turbine engine

Turboprop engine inlet anti-ice system operates

  • continuously.
  • cyclically dependant on weather conditions.
  • cyclically independent on weather conditions.
Diverdeep asking:

turbine engine theoretically has 2 sections the main one operates continuously and the second one operates cyclically to avoid overload of the electric system

Module 15. Gas turbine engine

The exhaust gas temperature (E.G.T ) indicator on a gas turbine engine provides a relative indication of the

  • turbine inlet temperature.
  • temperature of the exhaust gases as they pass the exhaust cone.
  • exhaust temperature.
Diverdeep asking:

The exhaust gas temperature (EGT) is typically defined as the gas temperature at the exit of the turbine
https://www.researchgate.net/publication/266673900_A_Review_of_Exhaust_Gas_Temperature_Sensing_Techniques_for_Modern_Turbine_Engine_Controls#:~:text=The%20exhaust%20gas%20temperature%20%28EGT%29%20is%20typically%20defined,parameter%20for%20optimizing%20fuel%20economy%2C%20diagnosis%2C%20and%20prognosis.

Module 15. Gas turbine engine

Nozzle guide vanes give a

  • pressure increase, velocity decrease.
  • pressure increase, velocity increase.
  • pressure decrease, velocity increase.
Diverdeep asking:

nozzle guide vane are associated with compression section, so they're used to maximise compression performance (they're divergent) by decrease the speed & increasing pressure gain for each stage

Module 15. Gas turbine engine

Nozzle guide vanes give a

  • pressure increase, velocity decrease.
  • pressure increase, velocity increase.
  • pressure decrease, velocity increase.
Diverdeep asking:

nozzle guide vane are associated with compression section, so they're used to maximise compression performance (they're divergent) by decrease the speed & increasing pressure gain for each stage

Module 15. Gas turbine engine

Upon what quality or characteristic of a lubricating oil is its viscosity index based?

  • Its rate of flow through an orifice at a standard temperature.
  • Its rate of change in viscosity with temperature change.
  • Its resistance to flow at a standard temperature as compared to high grade paraffin base oil at the same temperature.
Diverdeep asking:

viscosity is defined as mm^2/s for a determined temperature.

Module 15. Gas turbine engine

The working fluid of a gas turbine engine is

  • gasoline.
  • kerosene.
  • air.
MartonA98 asking:

Can anyone help me with this question?

Module 15. Gas turbine engine

Fire detection systems which are routed through another zone

  • must be protected by the use of heat sinks.
  • must be protected from heat sources in the zone.
  • are not allowed.
vale asking:

Aren't the first and second sentence saying the same thing? Can some one find a reference pls?

Module 15. Gas turbine engine

Where do stress rupture cracks usually appear on turbine blades?

  • Across the blade root, parallel to the fir tree.
  • Across the leading or trailing edge at a right angle to the edge.
  • Along the leading edge, parallel to the edge.
vale asking:

The first 2 answers aren't saying the same thing?

Module 15. Gas turbine engine

The purpose of the rotating guide vanes on a centrifugal compressor is to

  • direct the air smoothly into the impeller.
  • provide initial diffusing of the air.
  • prevent damage by solid objects.
Jordi asking:

can someone please explain to me?

Module 15. Gas turbine engine

Acoustic linings made from composite materials are used in what section of the engine?

  • Not used to suppress noise.
  • Hot section and Cold Section.
  • Cold section only.
Jordi asking:

i dont understand

Module 15. Gas turbine engine

For fire detection and extinguishing purposes, aircraft powerplant areas are divided into fire zones based on

  • the volume and smoothness of the airflow through engine compartments.
  • engine type and size.
  • hot and cold sections of the engine.
Jordi asking:

i think this asnwer is also wrong my pdf says "The zoning layout will depend on the characteristics of the
individual engin"

Module 15. Gas turbine engine

Following the reports of a heavy landing you would

  • carry out a complete visual examination of the power plant.
  • examine the engine mountings and borescope the nozzle guide vanes and turbine.
  • examine the engine mountings and fuse pins.
Jordi asking:

why not the mountings?

Module 15. Gas turbine engine

Screech liners in the afterburning jet pipe

  • prevent unstable combustion.
  • prevent cyclic vibrations of large amplitude.
  • acts as noise suppressors.
Jordi asking:

i think the answer is wrong my textbook says that they act as noise suppressors.I quote "These are commonly called as Noise suppression liners or Noise
attenuation mattresses. When installed in the exhaust area these
are also known as Screech liners"

Module 15. Gas turbine engine

What type of intake is one that decreases gradually in area and then increases?

  • Convergent.
  • Convergent / Divergent.
  • Divergent.
Jordi asking:

isnt this divergent only?Why can it be also convergent?I think convergent is the opposite of what it says.

Module 15. Gas turbine engine

Water methanol for cooling is injected into the

  • compressor inlet or outlet.
  • engine hot zone.
  • combustion chamber.
Jordi asking:

why isnt methanol injected into combustion to help with the freezing of water?

Module 15. Gas turbine engine

The velocity of supersonic air as it flows through a divergent nozzle

  • decreases.
  • increases.
  • is inversely proportional to the temperature.
Jordi asking:

why is it increasing?It isnt convergent,it is divergent.Can someone help?

Module 15. Gas turbine engine

An increase in the Ram Ratio of an intake will

  • have no effect upon the temperature of the compressed air.
  • increase the temperature of the compressed air.
  • decrease the temperature of the compressed air.
olegs leonovs asking:

I think the answer "C" or "3" is correct.

Module 15. Gas turbine engine

Air bleed valves are

  • closed at low RPM.
  • open at high RPM.
  • open at low RPM.
Ronit asking:

Please write your question here.

Module 15. Gas turbine engine

An H.M.U receives its signals from

  • E.C.
  • ADC.
  • thrust lever resolvers.
Ekio asking:

Hi,

EC reffers ECU??

Thanks

Module 15. Gas turbine engine

An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to

  • increase and the velocity to decrease.
  • decrease and the velocity to increase.
  • increase and the velocity to increase.
Ekio asking:

The type of duct that forms the exhaust cone will determine what happens with the pressure and temperature. I distinguish 2 types of cone and therefore 2 types of conduit:

1 / convergent - divergent
2 / divergent

Module 15. Gas turbine engine

Kerosene will burn effectively at an air/fuel ratio of

  • 150:1.
  • 15:1.
  • 45:1.
max.steelame asking:

but the mixture provided to the combustion chamber is of ratio 45:1

Module 15. Gas turbine engine

An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to

  • increase and the velocity to decrease.
  • decrease and the velocity to increase.
  • increase and the velocity to increase.
Pierre72 asking:

Please write your question here.

Module 15. Gas turbine engine

What are the principal advantages of the duplex fuel nozzle used in many turbine engines?

  • Allows a wider range of fuels and filters to be used.
  • Restricts the amount of fuel flow to a level where more efficient and complete burning of the fuel is achieved.
  • Provides better atomization and uniform flow pattern.
ta2x asking:

Please write your question here.

Module 15. Gas turbine engine

An abradable lining in the fan case

  • prevents fan blade tip rub.
  • produces less leakage at tips for anti-ice.
  • provides acoustic medium.
bucks asking:

how can it reduce noise?

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