FUEL Nozzle
- The final components of the fuel system are the fuel nozzles, which have as their essential function the task of atomizing or vaporizing the fuel to ensure its rapid burning.
- PT6 typical maintenance interval to clean 400hours, for new operators it’s recommended to start with an interval 200 hours. Fuel quality plays a significant role in fuel nozzle cleanliness.
- There are two types of fuel nozzles on PT6 engines simplex and duplex.
- With simplex fuel nozzles, primary and secondary.
- Each nozzle has a single orifice.
- Simplex nozzles are typically set up as either all primary (in some engines) or in a ratio of 7 to 7 or 10 to 4 primary to secondary.
- The configuration depends on the engine model and configuration status of the engine.
- Upon startup, fuel is distributed to the primary nozzles only. At a given N1, the secondary nozzles kick in.
- With duplex nozzles, fuel is introduced in a similar way as with a simplex nozzle system in two stages with primary spray upon startup and secondary kicking in as the engine spools up. The difference is that in a duplex nozzle system, all of the nozzles are identical. Each one has two passages and two concentric ports in the tip that spray fuel.
