DOC AIRBUS | AMM A320FAIR - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The air system covers primary, secondary (bypass) and parasitic (cooling and pressurizing) airflows and the systems used to control the airflow. It is composed of 2 major sections.
The air system covers primary, secondary (bypass) and parasitic (cooling and pressurizing) airflows and the systems used to control the airflow. It is composed of 2 major sections.
A. Engine Section
The airstream flowing through the engine supplies 2 major systems:
The airstream flowing through the engine supplies 2 major systems:
(1) The internal air system, which consists of the following subsystems:
(a) Propulsion airflow (secondary and primary flows).
(b) Front and rear bearing sump pressurizing air.
(c) Cooling air.
(d) Internal thrust balancing air.
(2) The external air system, which consists of the following subsystems:
(a) Fuel control system air.
(b) Low pressure turbine active clearance control.
(c) High-energy igniter harness cooling air.
(d) Engine bleed air.
(e) Turbine shroud cooling air.
(f) HPC rotor active clearance control system.
(g) ECU cooling.
B. Nacelle Section
The nacelle installation is designed to provide cooling and ventilation air for engine accessories mounted along the fan and core casing.
The distribution and circulation of the air in the components is such that the temperature limit for specific component is not exceeded.
The nacelle installation is designed to provide cooling and ventilation air for engine accessories mounted along the fan and core casing.
The distribution and circulation of the air in the components is such that the temperature limit for specific component is not exceeded.
2. Component Location
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| FIN I FUNCTIONAL DESIGNATION I PANELIZONEIACCESS I ATA |
| I I I I DOOR I REF. |
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| 13KS1 SENSOR - TEMP, ENG 1 NACELLE 415 451AL 75-41-15 |
| 13KS2 SENSOR - TEMP, ENG 2 NACELLE 425 461AL 75-41-15 |
3. Description
All engine air enters through the engine air intake cowl into the front mounted fan. After being compressed by the fan, the airflow is divided by the flow splitter in the fan frame into primary and secondary (bypass) airflows. The logics of the air systems controlled by the FADEC are fully described in chapter 73-20-00.
All engine air enters through the engine air intake cowl into the front mounted fan. After being compressed by the fan, the airflow is divided by the flow splitter in the fan frame into primary and secondary (bypass) airflows. The logics of the air systems controlled by the FADEC are fully described in chapter 73-20-00.
A. Propulsion Airflow System
(1) Secondary flow
Fan air passes through the Outlet Guide Vanes (OGV) and the fan frame struts.
Bypass air is discharged through the fan exit nozzle during normal engine functioning and provides the major portion of engine thrust (4/5 of the total airflow of the engine). When the thrust reverser is deployed, the fan exit nozzle is blocked and the bypass air is directed outward at a forward angle through the reverser pivoting doors to provide reverse thrust (Ref. AMM D/O 78-36-00-00). Some of the fan discharge air may come from the primary airflow through bypass valves located in the fan frame. A small portion of the bypass air is used for core engine compartment cooling and for low pressure turbine cooling and environmental control system cooling through the precooler.
Fan air passes through the Outlet Guide Vanes (OGV) and the fan frame struts.
Bypass air is discharged through the fan exit nozzle during normal engine functioning and provides the major portion of engine thrust (4/5 of the total airflow of the engine). When the thrust reverser is deployed, the fan exit nozzle is blocked and the bypass air is directed outward at a forward angle through the reverser pivoting doors to provide reverse thrust (Ref. AMM D/O 78-36-00-00). Some of the fan discharge air may come from the primary airflow through bypass valves located in the fan frame. A small portion of the bypass air is used for core engine compartment cooling and for low pressure turbine cooling and environmental control system cooling through the precooler.
(2) Primary flow
A portion of fan air passes into the 3-stage booster and enters the core by a converging duct formed by the fan frame. This duct is provided with Variable Bleed Valves (VBV). The compressed air enters the combustion chamber and is ignited with the fuel. The exhaust gases flow through the High Pressure Turbine (HPT) and the Low Pressure Turbine (LPT) and are discharged through the primary jet nozzle.
A portion of fan air passes into the 3-stage booster and enters the core by a converging duct formed by the fan frame. This duct is provided with Variable Bleed Valves (VBV). The compressed air enters the combustion chamber and is ignited with the fuel. The exhaust gases flow through the High Pressure Turbine (HPT) and the Low Pressure Turbine (LPT) and are discharged through the primary jet nozzle.
B. Front and Rear Bearing Sump Pressurizing Air
(1) A preferred direction of air circulation is established by pressurizing the labyrinth seals. This pressure exceeds the internal pressure of the sump.
(2) The sumps are vented to prevent overpressures in the sump. The air is vented by the center vent tube located inside the LPT shaft.
C. Engine Internal Cooling Air System
(1) Heat transfer is primarily attained by convection and conduction.
Radiation transfer is confined to the primary zone of the combustion chamber.
Radiation transfer is confined to the primary zone of the combustion chamber.
(2) The HPC/HPT rotor cooling air consists of booster discharge air that is bled internally and 5th stage HPC air that is modulated by the ECU and introduced externally through a pipe to the number three bearing cavity.
(3) Cooling air for the HPT blades is bled from the final stage of High Pressure Compressor (HPC).
(4) Cooling air for the HPT nozzle vanes is provided by air from the HPC discharge.
(5) Cooling air for the stage 1 of LPT vanes is taken from the HPC stage 5.
This air is also used to cool the stage 1 and 2 LPT disks. Cooling air for stage 3 and 4 LPT disks is taken from the HPC discharge.
This air is also used to cool the stage 1 and 2 LPT disks. Cooling air for stage 3 and 4 LPT disks is taken from the HPC discharge.
(6) Cooling air for the HPT clearance control is provided by air from 2 sources to optimize the HPT blade clearance. The air is taken from the HPC stages 5 and 9. The flow rate of each supply is regulated by the ECU according to engine operating conditions.
D. Internal Thrust Balancing Air System
The internal thrust balancing system limits the axial thrust applied to the Low Pressure (LP) and High Pressure (HP) rotors. This system prevents overloading of the thrust bearings.
The internal thrust balancing system limits the axial thrust applied to the Low Pressure (LP) and High Pressure (HP) rotors. This system prevents overloading of the thrust bearings.
E. Fuel Control System Air Bleed
(1) The air bled from the fan inlet provides static pressure PS12 evaluation.
This pressure serves as a control parameter for the Electronic Control Unit (ECU).
This pressure serves as a control parameter for the Electronic Control Unit (ECU).
(2) The air bled from the HPC stage 9 provides static pressure PS3 Compressor Discharge Pressure (CDP) evaluation. This pressure serves as another control parameter for the ECU.
F. External Cooling Air System
(1) The bay is cooled by air entering through scoops placed in the secondary airflow path. The bay consists of the engine, aircraft accessories, and the area between the primary flow fairing and the outer walls of the core engine casing.
(2) The LPT case is cooled by 2 outer cooling manifolds. Cooling air is provided by 2 air scoops located in fan airstream.
(3) Cooling air for the high-energy igniter harness is taken from the fan frame outlet near the bundle junction box.
G. Engine Bleed Air
Two customer bleeds are available at stages 5 and 9 of the HPC.
Two customer bleeds are available at stages 5 and 9 of the HPC.
(1) The anti-icing system of the air intake cowl consists of ducting routing from a 5th stage engine bleed port to the lip swirl nozzle of the air intake cowl.
An on-off valve controls the air supply to the air intake lip.
(Ref. AMM D/O 30-21-00-00).
An on-off valve controls the air supply to the air intake lip.
(Ref. AMM D/O 30-21-00-00).
(2) The pneumatic installation of the Environmental Control System (ECS) collects bleed air from either the engine 5th stage manifold or the engine 9th stage manifold and delivers the bleed air through a pressure regulating valve to the pylon/nacelle assembly interface (Ref. AMM D/O 36-11-00-00).
(3) ECS air cooling is provided through the precooler. The cooling air is taken from the fan discharge.
H. ECU Cooling
The ECU is cooled by air. This air flows and maintains ECU internal temperature within maximum limits.
The ECU is cooled by air. This air flows and maintains ECU internal temperature within maximum limits.
4. Nacelle Temperature Indication
Nacelle Temperature Indication Lower ECAM Display Unit ** ON A/C NOT FOR ALL
Nacelle Temperature Indication Lower ECAM Display Unit ** ON A/C NOT FOR ALL
This system enables the overtemperature indication to be displayed.
Nacelle Temperature Indication Lower ECAM Display Unit ** ON A/C NOT FOR ALL Nacelle Temperature Indication Lower ECAM Display Unit ** ON A/C NOT FOR ALL