DOC AIRBUS | AMM A320FNACELLE COMPARTMENT AND ACCESSORY COOLING - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The nacelle compartment and engine accessories are air cooled.
The cooling air is taken from the air flowing in and around the nacelle cowls.
There are three cooling systems:
Fan and core compartments.
Engine gearbox breather vent.
Air cooled oil cooler vent.
The nacelle cooling and ventilation systems provide the following functions:
Sufficient airflow to offset the effects of engine case heat rejection and engine flange air leakage, thereby maintaining an acceptable compartment temperature level.
Cooling of temperature critical components.
Ventilation of compartment during engine shutdown.
Ventilation of combustible fluid vapors to preclude fire.
** ON A/C NOT FOR ALL The nacelle compartment and engine accessories are air cooled.
The cooling air is taken from the air flowing in and around the nacelle cowls.
There are three cooling systems:
Fan and core compartments.
Engine gearbox breather vent.
Air cooled oil cooler vent.
The nacelle cooling and ventilation systems provide the following functions:
Sufficient airflow to offset the effects of engine case heat rejection and engine flange air leakage, thereby maintaining an acceptable compartment temperature level.
Cooling of temperature critical components.
Ventilation of compartment during engine shutdown.
Ventilation of combustible fluid vapors to preclude fire.
2. Description
A. Fan and Core Compartments Cooling
Fan Case and Core Compartments - Ventilation Paths(1) Fan case compartment accessories are cooled by air which enters through a scoop in the air intake cowl. A duct from this scoop goes to a Y-shaped outlet duct on the cowl aft bulkhead. The air comes out of this duct into the fan compartment.
(2) The air in the fan compartment is vented overboard through two outlet vents in the bottom of the fan cowl (one in each fan cowl door).
(3) Core compartment ventilation is provided by fan air through holes in the inner wall of the "C" ducts. Air circulates through the core compartment and exits through the exhaust orifice located in the lower bifurcation of the "C" ducts. This is supplemented by air exhausting from Active Clearance Control System around the turbine area.
(4) During ground running local pockets of natural convection provide some ventilation of the fan case zone.
(5) The fan compartment is sealed to keep the air in. Seals are installed at the following locations:
- Air intake cowl to fan cowl junction.
- Fan cowl door split line.
- Fan cowl to thrust reverser C-ducts junction.
- Gearbox breather to right fan cowl junction.
- ACOC outlet vent to right fan cowl junction.
(6) The maximum permitted air temperatures are:
- 230 degrees F (110 degrees C) at the top of the fan compartment
- 255 degrees F (124 degrees C) at the bottom of the fan compartment.
- 797 degrees F (425 degrees C) in the core compartment.
B. Engine Gearbox Breather Vent System
(1) The engine gearbox breather lets the gas from the gearbox go overboard from the nacelle. The gas goes through a breather duct on the gearbox and then a duct in the right hand side fan cowl. A seal is installed at duct junction.
(1) The air cooled oil cooler (ACOC) is cooled with air from the fan duct. The hot air goes overboard from the cooler through an outlet grille in the right fan cowl.