Exhaust Flashcards

1
Q

Main task of exhaust

A

Guide exhaust gas from rear of turbine into atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the exhaust do in a jet engine

A

Exhaust system accelerates airflow from turbine to make thrust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the apu do in exhaust

A

Guides exhaust gases overboard as all gas energy absorbed by the turbine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the exhaust system tube called

A

Exhaust duct or tail pipe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is the conical tube supported

A

At its forward end by turbine exhaust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where is the exhaust nozzle and what does it do

A

Aft of the exhaust duct and accelerates gasses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the exhaust cone do

A

Guides discharge flow and prevents excessive turbulence of the gases

Prevents reverse flow of exhaust gases into the hub of the turbine rear stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What’s the exhaust streams of a high bypass turbofan

A

Primary for hot gas

Secondary for cold air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What aircraft are combined exhaust nozzle used for

A

Modern long range aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does a combined exhaust nozzle work

A

Mixes gasses to reduce velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Advantage to common exhaust nozzle

A

Reduces exhaust gas velocity which higher propolsion efficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Disadvantage of common exhaust nozzle

A

Increases weight of engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the addition mixer do

A

Improves the mixing of hot and cold gas flow to get higher propulsion efficiency but also adds weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why must exhaust gasses expand completely

A

To achieve optimum thrust from the given mass

Guarantees a laminar vortex-free and axially oriented exhaust gas flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When is a convergent exhaust nozzle used

A

For max airflow with a pressure ratio up to 2:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When is convergent divergent nozzle used

A

For pressure ratios bigger then 2:1 for aircraft’s to fly faster then speed of sound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why are high exhaust gas velocities avoided

A

Decrease the propulsion efficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What unit is engine noise reduction

A

Effective Perceived Noise DeciBel EPNdB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What variable is engine noise dependent on

A

Velocity of gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

turbofan noise change depends on what ratio

A

Depending on bypass ratio

21
Q

How can we suppress noise

A

Reducing airflow disruption

Airflow lining are equipped with noise absorbing materials

22
Q

What is a porous surface made of and how does it minimise noise

A

Supported by honeycomb structures and converts sound energy into heat energy

23
Q

What are the two types of liner

A

Single and double

24
Q

How does a thrust reverser work

A

Producers a breaking force by deflecting exhaust gas stream to opposite direction

25
Q

Most ideal deflection angle

A

180 degrees but causes problems for engine

26
Q

What is the actual deflection angle

A

45-60 degrees

27
Q

What air is used for thrust reverser

A

Only Bypass air

28
Q

When are thrust reverses used

A

Only on ground

29
Q

How is the bucket on common thrust revereres operated

A

Hydraulically operated

30
Q

In a fan reverser what air is used

A

Cold fan is used which is secondary air

31
Q

What’s type of reverser is a fan reverser

A

Cascade type with translating sleeves

32
Q

How is a fan reverser operated

A

Pneumatically with drive motors

Hydraulically with actuators

33
Q

How are pivot door reversers activated

A

Hydraulically

34
Q

How can you minimise the disadvantages of reverse thrust

A

March reverse airflow with engine position

35
Q

Why is angle of reverse steam important on 4 engine aircraft

A

Reverse airflow of the inner engines can be ingested by outer engines

36
Q

What’s the use of a cascade vane

A

Directs the airflow of a thrust reverser

37
Q

What advantage do large aircraft’s have in regards to thrust reversers

A

They use the same cowlings which means they can use less parts

38
Q

Can aircraft’s be released to service with faulty thrust reversers

A

Yes

39
Q

What does the control system do

A

Actives thrust reverser and increase engine power

40
Q

What components does a reverser actuation system have

A

Pneumatic or hydraulic

41
Q

What does the airflow deflection system do

A

Directs airflow in optimum direction for safe reverse thrust

42
Q

What does thrust reverser interlock do

A

Makes sure engine power can only be increased once reverser is deployed

43
Q

Where are hydraulic reverser actuation systems used

A

Reversers with translating sleeves and cascade vanes

44
Q

What does thrust reverser locking system do

A

Makes sure reverser is locked and stowed

45
Q

Where are blocker doors

A

Linked between the fixed cowl and translating sleeve

46
Q

What are 4 cascade airflow directions

A

45 degrees up

45 degrees down

90 degrees straight

Some is blocked

47
Q

What does reverse unlock message indicate

A

Reverse is not safe in its stowed position

48
Q

What colour are reverse unlock messages

A

Amber & always shows when reverser moves from deployed to stowed

49
Q

When is the green reverse light show

A

Reverser fully deployed and throttle interlock is released so engine power can be increased for reverser thrust