Aerospace Propulsion Study For Shenyang Aerospace University by Lale420 (Final_Eaxm_3 )

Powerplant Fire

Protection System

1 Devinder K Yadav

System Overview

2

Fire Detection Methods

Rate of Temperature Rise Detector

Smoke Detector

Overheat Detector

Observation of Crew or Passenger

3

Fire Detection Systems

Thermal switch system

Thermocouple system

Continuous loop detector system (Used in turbine engines of

large transport aircraft)

4


Thermal switch system:

It uses a bimetallic

thermostat switch or spot

detector.

5


Thermocouple system: Works on rate of temperature rise.

Does not give warning when an engine slowly overheats.

6

Continuous - loop detector system

In case of fire, the core resistance drops and

current flows between the signal wires and the

ground, energising the alarm system


7

Continuous - loop detector system


8

Fire Protection Systems

9

A Typical Fire Detection Systems

10

Fire System Warnings

11

Fire Warning

12

Loop Warning

13

Fire Warning Schematic

14

Fire Warning Schematic

15

Fire Extinguishing Systems

Types of fires

16


Types of extinguishing systems

High Rate of Discharge (HRD) System: Provide high discharge rate through high pressurisation, short feed

lines, large discharge valves and outlets. Extinguishing agent is

released into the zone in one second or less.

Conventional System System is designed around a cylinder that stores the CO2 under

pressure and a remote control valve assembly in the cockpit to

distribute the extinguishing agent to the engine.

17

Conventional System

CO2 cylinder


18


19

Typical Fire Extinguishing Systems

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21


22

Typical Fire Extinguishing Systems Schematic

23

Gas Turbine

Ignition & Starting

Devinder K Yadav 1

Engine Ignition System

The Ignition system initiate combustion of the air/fuel mixture in the combustion chamber. Each System is composed of: A high energy ignition exciter An exciter-to-igniter plug lead An igniter plug

2

Engine Ignition System

3

Engine Ignition System Ignition Exciter

4

Ignition Systems

Spark systems are the most common

ignition system used with gas turbine

engines

Once the flame is started and stabilised

the ignition system is switched off

If potential flame-out conditions exist the

ignition system may be activated 5

Typical Ignition System

Large transport aircraft are fitted with two independent ignition systems. System A System B

6

Ignition Systems

Whenever there is a flame-out risk

such as flying in rain or turbulence

ignition systems are generally switched

on and operate continuously

This gives an immediate re-light in the

event of a flame out

7

Typical Ignition System Operation

8


Continuous relight is recommended for turbulent weather operation, flameout, and inflight relight situations

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10

Engine Starting System

11

Turbine Engine Starting

For double and triple spool engines only

the high(est) pressure spool is rotated

The most common types of

starting systems used in civil

aircraft are

electric

pneumatic

12

Gas Turbine Engine Starting

The starter motor must accelerate the

compressor to provide sufficient air

under pressure to support combustion

Once fuel has been introduced and

ignited the starter motor must continue

to assist the engine to a self sustaining

speed

13

Turbine Engine Starting Systems

Both electric and pneumatic starters have

very high power to weight ratios

Operating times are very limited

Overheating will result from exceeding

limits

Turbine starters have defined duty cycles

for both times on and cool down times

14

Electric Starters

Used on small turbofans turboprop and

turboshaft engines

Aircraft battery or Ground Power Unit

(GPU)

GPU power supply must be carefully

monitored

15

Pneumatic Starters

Mainly used on large turbojet and

turbofan engines

Air impingement is supplied by either a

ground power unit, typically an Auxiliary

Power Unit (APU) or bleed air supply

from an operating engine

16

Pneumatic Starters

17

Pneumatic Starters

18

Pneumatic Starters

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Pneumatic Starters

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Pneumatic Starters

21

Engine Starting Sequence

Ref: www.faa.gov 22

Engine Starting Sequence

Ref: www.smartcockpit.com 23

Typical Starting System (A310)


Typical Starting Procedure


Typical

Starting

Procedure


Being 747-400 Overhead Panel

www.avsim.com 28

Being 747-400 pedestal Panel

www.avsim.com 29

Being 747-400 pedestal Panel

www.avsim.com 30

Starting Procedure B747-400

Select Ignition as desired (ignition 1). Pull the Engine Start Selector for Engine 4 . Watch the N2% RPM increase in the EICAS display. Bleed air from the APU is being supplied to starter and it begins to turn the compressor (N2). Check for visual N1 rotation. When the N2% RPM indicator on the EICAS reaches max motoring speed around 15%), switch the Fuel Control Switch for Engine 4. Watch for Max EGT, oil pressure and other parameters

www.avsim.com 31

Hot Starts

Premature cut out of the starter motor

will cause the fuel control unit to

automatically supply extra fuel to

maintain a programmed acceleration rate

If light-up occurs too early the airflow is

insufficient to accommodate the light-up

fuel flow resulting in an over rich

mixture and high turbine temperature

32

Hot starts

If there is insufficient torque from the

starter motor the fuel control unit will

automatically supply extra fuel to maintain

a programmed acceleration rate

Defective compressors or turbines

wastes energy available for acceleration

Abnormally high propeller or accessory

loads also waste energy 33

Hot Starts

An engine start must be abandoned if it

is apparent that starting turbine

temperatures will be exceeded

A hot start is abandoned by cutting the

fuel supply then motoring the engine for

a short period to reduce turbine

temperature

34

Hung Starts

A hung start is a potentially dangerous

situation where the engine fails to

accelerate past a certain RPM during

starting

Causes are as for a hot start

The engine start must be abandoned if

the RPM hangs or the duty cycle of the

starter motor is exceeded 35

BGT 7 Fire Protection Systems.pdfBGT 8 Ignition & Starting System.pdf

Engineering

Aerospace Propulsion Study For Shenyang Aerospace University by Lale420 (Final_Eaxm_3 )