DOC AIRBUS | AMM A320FAIR - GENERAL - 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 (by pass) and parasitic (cooling and pressurizing) airflows and the systems used to control airflow.
The air system covers primary, secondary (by pass) and parasitic (cooling and pressurizing) airflows and the systems used to control airflow.
Engine AirflowA. Engine Section
The airstream flowing through the engine supplies air systems using propulsion airflow (secondary and primary flows) or ambient air.
The airstream flowing through the engine supplies air systems using propulsion airflow (secondary and primary flows) or ambient air.
(g) Engine bleed air.
(3) Engine Control
(a) Fuel control system air.
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. Description
All engine air enters through the engine air inlet cowl, 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.
Propulsion Airflow System
All engine air enters through the engine air inlet cowl, 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.
Propulsion Airflow System
- 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. chap. 78-36-00). Some of the fan discharge air may be 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. - Primary flow
A portion of fan air passes into the 4-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. Engine anti-icing
Air from 5th stage compressor is used to de-ice inlet cowl in case of icing conditions (Ref. AMM D/O 30-21-00-00).
Air from 5th stage compressor is used to de-ice inlet cowl in case of icing conditions (Ref. AMM D/O 30-21-00-00).
(1) Front and Rear Bearing Sump Pressurizing Air
(a) A preferred direction of air circulation is established by means of pressurizing the labyrinth seals. This pressure exceeds the internal pressure of the sump.
(b) The sumps are vented to prevent overpressures in the sump. The air is vented by the center vent tube located inside the LPT shaft.
(a) Heat transfer is primarily attained by convection and conduction.
Radiation transfer is confined to the primary zone of the combustion chamber.
Core zone is cooled using compressor flow.
Fan zone is cooled using ambient air.
Radiation transfer is confined to the primary zone of the combustion chamber.
Core zone is cooled using compressor flow.
Fan zone is cooled using ambient air.
(a) 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.
(a) Cooling air for the HPT blades is bled from the final stage of high pressure compressor (HPC).
(b) Cooling air for the HPT nozzle vanes is provided by air from the HPC discharge.
(c) 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 4 and 9. The flow rate of each supply is regulated by the ECU according to engine operating conditions.
(d) Cooling air for the stage 1 of LPT vanes is taken from the HPC stage 4.
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.
(a) The LPT case is cooled by 2 outer cooling manifolds. Cooling air is provided by 2 air scoops located in fan airstream.
(a) Cooling air for the high-energy igniter harness is taken from the fan frame outlet near the bundle junction box.
(7) 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.
(a) The air intake cowl anti-icing system consists of ducting routing from a 5th stage engine bleed port to the air intake cowl lip swirl nozzle.
An on-off valve control the air supply to the air intake lip.
(Ref. AMM D/O 30-21-00-00).
An on-off valve control the air supply to the air intake lip.
(Ref. AMM D/O 30-21-00-00).
(b) The environmental control system (ECS) pneumatic installation 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).
(c) ECS air cooling is provided through the precooler by air taken in the fan discharge.
(8) ECU Cooling
(Ref. AMM D/O 75-24-00-00)
The ECU is cooled by air. This air flows and maintains ECU internal temperatures within maximum limits.
(Ref. AMM D/O 75-24-00-00)
The ECU is cooled by air. This air flows and maintains ECU internal temperatures within maximum limits.
C. Engine control
(a) 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).
(b) 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.
(2) Compressor control
(Ref. AMM D/O 75-30-00-00)
The variable stator vane (VSV) and the variable bleed valve (VBV) are controlled by the ECU.
The VSV system controls the air flow (primary) through the compressor downstream of the booster. The variable stator vane actuators position the inlet guide vanes and stator vanes as scheduled by the ECU through HMU.
The VBV system automatically schedules the total opening by positioning the valves as a function of corrected core and corrected fan speed.
(Ref. AMM D/O 75-30-00-00)
The variable stator vane (VSV) and the variable bleed valve (VBV) are controlled by the ECU.
The VSV system controls the air flow (primary) through the compressor downstream of the booster. The variable stator vane actuators position the inlet guide vanes and stator vanes as scheduled by the ECU through HMU.
The VBV system automatically schedules the total opening by positioning the valves as a function of corrected core and corrected fan speed.
(3) Variable Bleed Valve system
(Ref. AMM D/O 75-31-00-00)
The variable bleed valve (VBV) position is related to the high pressure compressor (HPC) operation. It is directly controlled by the angular setting of the variable compressor stator vanes at steady-state operation and during acceleration. The bleed valves open during low and transient operations to increase the booster mass flow and to improve booster and HPC matching. The bleed valves are fully open during fast decelerations.
(Ref. AMM D/O 75-31-00-00)
The variable bleed valve (VBV) position is related to the high pressure compressor (HPC) operation. It is directly controlled by the angular setting of the variable compressor stator vanes at steady-state operation and during acceleration. The bleed valves open during low and transient operations to increase the booster mass flow and to improve booster and HPC matching. The bleed valves are fully open during fast decelerations.
(4) Variable Stator Vane system
(Ref. AMM D/O 75-32-00-00)
The variable stator vane (VSV) actuation system consists of 2 VSV hydraulic actuators with dual independent transducers (LVDT) for position feedback, and 2 actuation mechanisms and linkages. Fuel pressure from the hydromechanical unit is the hydraulic medium used to operate the VSV actuators.
(Ref. AMM D/O 75-32-00-00)
The variable stator vane (VSV) actuation system consists of 2 VSV hydraulic actuators with dual independent transducers (LVDT) for position feedback, and 2 actuation mechanisms and linkages. Fuel pressure from the hydromechanical unit is the hydraulic medium used to operate the VSV actuators.
D. Indicating
Nacelle temperature indicating is described in 75-41-00.
Nacelle temperature indicating is described in 75-41-00.
3. 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 |