Chapter 6: Exhaust Flashcards
purpose of exhaust
accelerate gas efficiently
when is gross thrust maximum?
exhaust is perfectly expanded
exhaust design qualities
1) efficient expansion of gas to atm pressure
2) low drag, noise & cooling requirements
3) efficient thrust reversing / vector
how can reduction of noise be achieved?
mixing rate is accelerated
exhaust velocity relative to atm is reduced
what is siphoning effect?
siphon low speed air with high speed air to reduce friction (lesser noise)
advantage & disadvantage for noise-absorbing lining usage
adv: powerful noise supression technique for exhaust
disadv: increase in weight and drag
when is reverse thrust applied?
immediately after touchdown
can reverse thrust be used for long duration?
no, reingestion of hot air into engine
types of thrust reversal system
1) bucket target (clamshell)
2) translating sleeve (cold stream)
components of translating sleeve system
1) translating sleeve
2) cascade vane
3) blocker doors
what is the use of translating sleeve in translating sleeve system?
sleeve moves aftward to allow bypass air to escape
what is the use of cascade vane in translating sleeve system
directs air out at an angled direction
what is the use of blocker doors in translating sleeve system
block bypass air from exiting from exhaust, deflects air out to cascade vane
how is reverse thrust done on turboprop?
changing pitch of propeller blades to -ve AOA
