Turbine Design

Question 1

What is it called when combustion occurs at a constant pressure?

Answer 1

Brayton Cycle

Question 2

What happens when you have a hung start on a turbine engine?

Answer 2

Compressor fails to reach idle RPM
Shut it down

Question 3

In the hot section of a jet engine, it is susceptible to what type of damage?

Answer 3

Cracking

Question 4

The turbine jet nozzle is located in what section?

Answer 4

Exhaust

Question 5

What is used to do internal inspections on a turbine engine?

Answer 5

Borescope

Question 6

In the turbine section, what is the most common type of blade attachment?

Answer 6

Fir tree

Question 7

What type of compressor has the greatest rise in pressure per stage?

Answer 7

Centrifugal flow compressors

Question 8

When supersonic air flows through a divergent nozzle, what happens to pressure and velocity?

Answer 8

Pressure decreases
Velocity increases

Question 9

The compression ratio of an axial compressor is the function of..?

Answer 9

Number of compression stages

Question 10

Time Before Overhaul (TBO) is established by..?

Answer 10

The manufacturer

Question 11

The primary advantage of axial compressor over centrifugal is?

Answer 11

High peak efficiency of airflow

Question 12

At what stage on a turbine engine is the air pressure the greatest?

Answer 12

Diffuser

Question 13

What is standard sea level pressure?

Answer 13

29.92 Hg

Question 14

In a dual axial compressor, the first stage turbine drives the…?

Answer 14

N2 high pressure compressor and accessories

Question 15

Anti-ice in air inlet is usually accomplished through the use of…?

Answer 15

Bleed air

Question 16

The process for removing dirt from compressor blades is called…?

Answer 16

Field cleaning

Question 17

Where is the highest heat to metal contact?

Answer 17

Turbine Inlet Guide Vanes

Question 18

Heat and centrifugal force on a turbine blade is likely to cause..?

Answer 18

Growth, Stretching, Creep

Question 19

What type of turbine engine produces all of its thrust by imparting a high exit velocity to the exhaust gases as it leaves the exhaust duct?

Answer 19

Turbojet

Question 20

What compressor uses an impeller to compress the incoming air?

Answer 20

Centrifugal

Question 21

If the RPM of an axial flow compressor remains constant, the angle of attack of the rotor blades are changed by…?

Answer 21

Inlet velocity changes

Question 22

The EPR readings are taken from what two stations of a jet engine?

Answer 22

Front compressor (intake) Pt2
Rear of turbine (exhaust) Pt7

Question 23

What is the proper sequence to starting a turbine engine?

Answer 23

Starter, Ignition, Fuel

Question 24

What effects does the exhaust cone have on pressure and velocity? Is it convergent or divergent?

Answer 24

Divergent
Velocity decreases
Pressure increases

Question 25

For a turbofan engine, the turbofan ratio speed is the same as what?

Answer 25

N1 low pressure compressor

Question 26

When the variable bleed valves are in the open position, the variable inlet guide vanes are in what position?

Answer 26

Closed

Question 27

Where is the diffuser located?

Answer 27

After compressor, before turbine

Question 28

Fan blade shingling is caused by..?

Answer 28

FOD & Overspeed

Question 29

What is the function of the inlet guide vanes?

Answer 29

Direct air at the proper angle

Question 30

What is the major function of the high pressure N2 turbine section?

Answer 30

Drives the compressor

Question 31

What is a shrouded turbine?

Answer 31

It prevents air from flowing over the blade tips

Question 32

What is Newton’s third law?

Answer 32

Every action has an equal and opposite reaction

Question 33

What does subsonic air do through a convergent duct?

Answer 33

Increase velocity Decrease pressure

Question 34

What instrument shows the first indication of a good start?

Answer 34

EGT

Question 35

How do you re-install turbine/fan blades?

Answer 35

The same slot removed from

Question 36

If you remove a fan blade and replace it with one of a different weight, what must you also do?

Answer 36

Must replace the blade at 180 degrees as well

Question 37

In a dual axial compressor, what drives the gear box?

Answer 37

N2 High pressure

Question 38

How does the stator vane assembly affect the velocity of air in an axial flow compressor?

Answer 38

Converts velocity energy to pressure energy

Question 39

In a dual spool compressor, what does the low speed N1 compressor do?

Answer 39

Seeks out its own best operating speed

Question 40

Stators in a turbine section changes the air flow in what way?

Answer 40

Increases velocity

Question 41

What does the cold section of a turbine engine consist of?

Answer 41

Compressor and Diffuser

Question 42

Why do turbines have more than one turbine wheel?

Answer 42

To extract more power from the exhaust

Question 43

What is meant by double entry centrifugal compressor?

Answer 43

Two impellers on both sides

Question 44

What should be done if an engine experiences a tail pipe fire?

Answer 44

Shut off fuel and continue cranking

Question 45

What can be used to write on a turbine?

Answer 45

Chalk, Layout dye, Commercial felt tip marker

Question 46

What is the purpose of the propagation tubes in a can-annular combustion section?

Answer 46

Carries the flame to the other cans

Question 47

What effect does humidity have on a jet engine?

Answer 47

Negligible