2.
 Component Location

__________________
 (Ref. Fig. 001)

 -------------------------------------------------------------------------------FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA | | | | DOOR | REF. -------------------------------------------------------------------------------MANIFOLD - PRIMARY FUEL 315/ 315AL/ 49-31-41 316 316AR MANIFOLD - SECONDARY FUEL 315/ 315AL/ 49-31-42 316 316AR NOZZLES - PRIMARY FUEL 315/ 315AL/ 49-31-41 316 316AR NOZZLES - SECONDARY FUEL 315/ 315AL/ 49-31-42 316 316AR

 Fuel Distribution - Component Location
 Figure 001

 CES  3. System Description

__________________
 (Ref. Fig. 002)

 A. Fuel Atomizers and Manifolds
 (1) The APU has 6 dual orifice fuel-nozzles. They are installed in equal distances around the outer case of the combustion chamber. This makes sure that the temperature in the combustion chamber is equally divided. Each fuel nozzle has a primary and a secondary fuel orifice. The primary orifices give accurate fuel atomization at low fuel quantity and pressure. They get a controlled fuel supply from the FCU through the flow divider and drain valve assembly (FDDVA). This is controlled by the ECB 59KD logics, during start, operation and shutdown. The secondary orifices get the fuel when the start sequence valve is open, they provide accurate fuel atomization at high fuel consumption.
 4. Interface
_________
 The fuel distribution system has interfaces with:

 -
the APU drain system (Ref. 49-17-00),

 -
the APU fuel control (Ref. 49-32-00),

 -
the APU fuel pump system (Ref. 28-22-00),

 -
the APU LP fuel shutoff system (Ref. 28-29-00).

 5. Component Description
_____________________
 (Ref. Fig. 003)

 A. Primary and Secondary Fuel Nozzle and Manifolds
 (1)
 The primary and the secondary fuel manifolds are insulated, flexible lines. The fittings connect the manifolds to the flow divider assy and to the fuel nozzles.

 (a) 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 two flow paths. The orifices of the primary and the secondary flow paths are concentric.

 (a) The connectors to the fittings of the manifold are of different diameters. Filters are installed in the flow paths. The nozzle housing goes into the air shroud. The air shroud protects the atomizer 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.

 APU Fuel Distribution - Block Diagram
 Figure 002

 CES

 Dual Orifice Fuel Nozzle
 Figure 003

 CES

 6. Operation/Control and Indication________________________________ (Ref. Fig. 002)
 A. APU Start The fuel from the FDDVA flows to the primary fuel manifold. The primary fuel manifold then distributes the fuel to the primary fuel nozzles through the flexible lines. When the fuel flow is approximatly 44 lb (19.9580 kg) the fuel from the FDDVA also flows to the secondary fuel manifold. The secondary fuel manifold then distributes the fuel to the secondary fuel nozzles through the flexible lines.
 B. APU Normal Operation All fuel from the FDDVA flows through the primary and secondary manifolds to the primary and secondary fuel nozzles.
 C. APU Shutdown When the APU shuts down, the FDDVA purges with the combustion chamber pressure the remaining fuel in the primary and secondary manifold to the APU drain system.

 FUEL DISTRIBUTION - DESCRIPTION AND OPERATION
_____________________________________________
 1. General_______
 A. Fuel Distribution Incoming fuel from the A/C fuel system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the SCV. Returned fuel is routed back into the FCU. The FCU also pressurizes and meters the fuel for APU operation. The fuel is passed through the flow divider assy to the primary and/or secondary fuel manifold. These deliver the fuel to the 10 dual-orifice fuel nozzles, located around the circumference of the combustion chamber. There the fuel is atomized.
 2. Component Location__________________ (Ref. Fig. 001)
 -------------------------------------------------------------------------------FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA | | | | DOOR | REF. -------------------------------------------------------------------------------MANIFOLD - PRIMARY FUEL 315/ 315AL/ 49-31-43 316 316AR MANIFOLD - SECONDARY FUEL 315/ 315AL/ 49-31-44 316 316AR NOZZLE - PRIMARY AND SECONDARY FUEL 315/ 315AL/ 49-31-45 316 316AR
　
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