Turbine Engine Exhaust Section

Question 1

What is the shape of the duct formed by the cone and the wall of the exhaust section (propelling or outlet nozzle) ?

Answer 1

Convergent

Question 2

Why are convergent - divergent nozzles incorporated into exhaust system design?

Answer 2

Used in transonic and supersonic aircraft where exhaust flow is supersonic. Shockwave at the throat causes further acceleration of the flow and creates pressure thrust. To maximise cruise thrust and reduce engine noise.

Question 3

What component of the exhaust system is designed to straighten the gas flow exiting the engine?

Answer 3

The rear turbine exhaust cone support struts.

Question 4

What is the purpose of thrust reversal?

Answer 4

To assist the brakes to stop the aircraft during landing or RTO, thereby reducing stopping distance.

Question 5

Up to what angle does the reverse thrust system change the exhaust gas flow?

Answer 5

Up to about 135 degrees.

Question 6

What are the three types of thrust reverser?

Answer 6

Thrust revesers can be of either the clamshell, the bucket or the coldstream /cascade types

Question 7

What is the function of the blocker doors on a cold stream thrust reverser system?

Answer 7

To divert the bypass air outward and forward.

Question 8

What safeguards are designed into the thrust reverser system to prevent inadvertent deployment in flight?

Answer 8

Mechanical, hydraulic and /or electrical interlocks and isolation valves, as well as air/ground sensor switches.

Question 9

What actions should the pilots take if a thrust reverser unlocked light comes on in flight?

Answer 9

Be prepared to shut the engine down immediately if yaw, significant loss of airspeed or buffet is detected (indicating thrust reverser deployment).

Question 10

In which type of engine is compressor and turbine noise the biggest issue?

Answer 10

In a high bypass turbofan.