DOC AIRBUS | AMM A320FNACELLE COMPARTMENT AND ACCESSORY COOLING - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The nacelle has three major compartments ; the engine air intake, fan and core compartments. Each compartment is isolated from the other with separating bulkheads and seals. The fan and core compartments surround the engine and are exposed to engine case heat and vapors from fluid leaks. These two compartments are cooled with forced air and have designed ventilation porting.
Ventilation air enters the fan compartment through two inlet scoops mounted on the inlet cowl outer barrel and flush with it. Air is ducted through the inlet cowl aft bulkhead and is introduced into the upper and lower forward portion of the fan compartment. Air passes down through the fan compartment and around the accessory gearbox to cool the components and carry away any vapor. The air exits the fan compartment through the vent port located in the lower aft section of the right hand fan cowl door. The vents are sized to relieve the air starter flow at high altitudes since the starter motor exhausts directly into the fan compartment.
A pressure relief door is located in the right hand fan cowl door. It is sized to prevent fan compartment pressure from exceeding 4 psid in the event of pneumatic duct burst.
The core compartment is cooled with air taken from the fan discharge path through flush inlets. The air is vented at the rear of the compartment at the core cowl/primary nozzle interface.
Deflection of the core cowl structure provides sufficient additional relief area in the event of a pneumatic duct rupture.
The nacelle cooling and ventilation systems provide the following functions:
** ON A/C NOT FOR ALL The nacelle has three major compartments ; the engine air intake, fan and core compartments. Each compartment is isolated from the other with separating bulkheads and seals. The fan and core compartments surround the engine and are exposed to engine case heat and vapors from fluid leaks. These two compartments are cooled with forced air and have designed ventilation porting.
Nacelle Cooling in FlightVentilation air enters the fan compartment through two inlet scoops mounted on the inlet cowl outer barrel and flush with it. Air is ducted through the inlet cowl aft bulkhead and is introduced into the upper and lower forward portion of the fan compartment. Air passes down through the fan compartment and around the accessory gearbox to cool the components and carry away any vapor. The air exits the fan compartment through the vent port located in the lower aft section of the right hand fan cowl door. The vents are sized to relieve the air starter flow at high altitudes since the starter motor exhausts directly into the fan compartment.
A pressure relief door is located in the right hand fan cowl door. It is sized to prevent fan compartment pressure from exceeding 4 psid in the event of pneumatic duct burst.
The core compartment is cooled with air taken from the fan discharge path through flush inlets. The air is vented at the rear of the compartment at the core cowl/primary nozzle interface.
Deflection of the core cowl structure provides sufficient additional relief area in the event of a pneumatic duct rupture.
The nacelle cooling and ventilation systems provide the following functions:
- Sufficient airflow to offset the effects of engine case heat and engine flange air leakage, thereby maintaining an acceptable compartment temperature level.
- Cooling of temperature critical components.
- Cowling pressure load limiting in the event of pneumatic duct failures.
- Ventilation of compartment during engine shutdown.
- Ventilation of combustible fluid vapors to preclude fire.
2. Description
The fan compartment ram air scoop and vent ports are of a low pressure load flush design. The 7 core compartment air inlets are located in the core cowl and provide fan air to obtain the necessary cooling. LPT case cooling air also contributes to compartment ventilation. Fan discharge air is drawn through the LPT ram air scoop mounted on the fan thrust reverser core cowl, routed through engine mounted ducting, and discharged on the engine LPT case. An engine mounted valve controls the LPT cooling air flow. The LPT and core compartment cooling air passes through the compartment and is discharged out of an annular opening between the fan thrust reverser and the core nozzle.
** ON A/C NOT FOR ALL The fan compartment ram air scoop and vent ports are of a low pressure load flush design. The 7 core compartment air inlets are located in the core cowl and provide fan air to obtain the necessary cooling. LPT case cooling air also contributes to compartment ventilation. Fan discharge air is drawn through the LPT ram air scoop mounted on the fan thrust reverser core cowl, routed through engine mounted ducting, and discharged on the engine LPT case. An engine mounted valve controls the LPT cooling air flow. The LPT and core compartment cooling air passes through the compartment and is discharged out of an annular opening between the fan thrust reverser and the core nozzle.
3. Engine and Aircraft Accessory Cooling
The aircraft installation is designed to provide cooling and ventilation air for aircraft engine accessories mounted on the fan and core casing.
The distribution and circulation of the air in the compartments are such that the temperature limit for specific components is not exceeded. These limits ensure long life and provide good fire safety margins.
The aircraft installation is designed to provide cooling and ventilation air for aircraft engine accessories mounted on the fan and core casing.
The distribution and circulation of the air in the compartments are such that the temperature limit for specific components is not exceeded. These limits ensure long life and provide good fire safety margins.