DOC AIRBUS | AMM A320FFUEL DISTRIBUTION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
Incoming fuel from the A/C APU fuel supply system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the BCV-actuator. Returned fuel from the actuators is routed back into the FCU fuel inlet.
The FCU also pressurizes and meters the fuel destined for APU operation. The fuel is ducted via a supply line to the flow divider, which distributes the fuel, depending on APU operating conditions, to the pilot and/or main fuel manifold. These deliver the fuel to the 3 pilot fuel injectors and/or the 6 main fuel injectors, located around the circumference of the combustion chamber. There the fuel is atomized.
** ON A/C NOT FOR ALL Incoming fuel from the A/C APU fuel supply system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the BCV-actuator. Returned fuel from the actuators is routed back into the FCU fuel inlet.
The FCU also pressurizes and meters the fuel destined for APU operation. The fuel is ducted via a supply line to the flow divider, which distributes the fuel, depending on APU operating conditions, to the pilot and/or main fuel manifold. These deliver the fuel to the 3 pilot fuel injectors and/or the 6 main fuel injectors, located around the circumference of the combustion chamber. There the fuel is atomized.
2. Component Location
** ON A/C NOT FOR ALL 
Fuel Distribution - Component Location| ------------------------------------------------------------------------------- |
| FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA |
| | | | | DOOR | REF. |
| ------------------------------------------------------------------------------- |
| 8020KM MANIFOLD - MAIN FUEL 315/ 315AL/ 49-31-41 |
| 316 316AR |
| 8021KM MANIFOLD - PILOT FUEL 315/ 315AL/ 49-31-42 |
| 316 316AR |
A. Pilot Fuel Nozzle
Three pilot fuel nozzles are installed in the combustor housing assembly at 120 degree intervals.
Three pilot fuel nozzles are installed in the combustor housing assembly at 120 degree intervals.
B. Main Fuel Nozzle
Six main fuel nozzles are installed around the circumference of the combuster housing assembly. The nozzles are equally spaced at 60 degree intervals.
Six main fuel nozzles are installed around the circumference of the combuster housing assembly. The nozzles are equally spaced at 60 degree intervals.
C. Pilot Fuel Manifold
The flexible pilot fuel manifold connects to the pilot fuel nozzles. Fuel is supplied to the pilot fuel nozzles by the pilot fuel manifold once the fuel flow divider cracking pressure is reached.
The flexible pilot fuel manifold connects to the pilot fuel nozzles. Fuel is supplied to the pilot fuel nozzles by the pilot fuel manifold once the fuel flow divider cracking pressure is reached.
D. Main Fuel Manifold
The flexible main fuel manifold connects to the main fuel nozzles. Fuel is supplied to the main fuel nozzles by the manifold during all phases of engine operation.
The flexible main fuel manifold connects to the main fuel nozzles. Fuel is supplied to the main fuel nozzles by the manifold during all phases of engine operation.
4. Interface
The fuel distribution system has interfaces with:
** ON A/C NOT FOR ALL The fuel distribution system has interfaces with:
- the APU fuel control (Ref. AMM D/O 49-32-00-00),
- the APU fuel pump system (Ref. AMM D/O 28-22-00-00),
- the APU LP fuel shutoff system (Ref. AMM D/O 28-29-00-00).
A. Pilot Fuel Nozzle and Manifold
(1) The pilot fuel manifold is insulated flexible line. The fittings connect the manifold to the flow divider assy and to the fuel nozzles.
The flexible lines are made from teflon tubes and a single layer of steel braid makes them stronger. The fuel-tight steel fittings have conical contact faces. Rubber sheaths protect the braids.
The flexible lines are made from teflon tubes and a single layer of steel braid makes them stronger. The fuel-tight steel fittings have conical contact faces. Rubber sheaths protect the braids.
(2) The fuel nozzles have one flow path. The nozzle housing goes into the air shroud. The air shroud protects the nozzle housing against the heat in the combustion chamber and guides air to the nozzle orifice. The air helps to atomize the fuel and makes a mixture with it.
B. Main Fuel Nozzle and Manifold
(1) The main fuel manifold is insulated flexible lines. The fittings connect the manifold to the flow divider assy and to the fuel nozzles.
The flexible lines are made from teflon tubes and a single layer of steel braid makes them stronger. The fuel-tight steel fittings have conical contact faces. Rubber sheaths protect the braids.
The flexible lines are made from teflon tubes and a single layer of steel braid makes them stronger. The fuel-tight steel fittings have conical contact faces. Rubber sheaths protect the braids.
(2) The fuel nozzles have one flow path. A filter is installed in the flow path. The nozzle housing goes into the air shroud. The air shroud protects the nozzle housing against the heat in the combustion chamber and guides air to the nozzle orifices. The air helps to atomize the fuel and makes a mixture with it.
6. Operation/Control and Indicating
A. APU Start
All fuel from the flow divider flows to the pilot fuel manifold. When the pressure increases to 20 psi (1.3790 bar) the pilot fuel manifold then distributes the fuel to the 3 pilot fuel nozzeles through the flexible lines.
When the fuel pressure is more than 200 psi (13.7895 bar) the fuel from the flow divider also flows to the main fuel manifold. The main fuel manifold then distributes the fuel to the 6 main fuel nozzeles through the flexible lines.
All fuel from the flow divider flows to the pilot fuel manifold. When the pressure increases to 20 psi (1.3790 bar) the pilot fuel manifold then distributes the fuel to the 3 pilot fuel nozzeles through the flexible lines.
When the fuel pressure is more than 200 psi (13.7895 bar) the fuel from the flow divider also flows to the main fuel manifold. The main fuel manifold then distributes the fuel to the 6 main fuel nozzeles through the flexible lines.
B. APU Normal Operation
The fuel from the flow divider flows through the pilot and main manifold to the pilot and main fuel nozzles.
The fuel from the flow divider flows through the pilot and main manifold to the pilot and main fuel nozzles.
C. APU Shutdown
When the APU shuts down, the flow divider purges with the combustion chamber pressure the remaining fuel in the main manifold to the exhaust system.
When the APU shuts down, the flow divider purges with the combustion chamber pressure the remaining fuel in the main manifold to the exhaust system.