Why does a duplex fuel nozzle usually require a dual fuel manifold?

Why does a duplex fuel nozzle usually require a dual fuel manifold?

• A. To provide redundancy in case of valve failure.
• B. To reduce weight and complexity.
• C. To divide primary and secondary (main) fuel flow.
• D. To improve spray pattern.

Answer: (C)

Having two separate fuel circuits in a duplex nozzle means the fuel for the ignition/primary portion and the fuel for the main (secondary) portion must be fed independently. This requires a dual fuel manifold so each circuit can be metered and delivered separately, ensuring the right amount of fuel reaches the primary passages for reliable starting and ignition, while the main circuit supplies the bulk of fuel for stable, efficient combustion at higher power settings. The separate manifolds prevent cross-flow between circuits and allow each path to be tuned for its specific role, which is why dividing primary and secondary fuel flow is essential.

Having two separate fuel circuits in a duplex nozzle means the fuel for the ignition/primary portion and the fuel for the main (secondary) portion must be fed independently. This requires a dual fuel manifold so each circuit can be metered and delivered separately, ensuring the right amount of fuel reaches the primary passages for reliable starting and ignition, while the main circuit supplies the bulk of fuel for stable, efficient combustion at higher power settings. The separate manifolds prevent cross-flow between circuits and allow each path to be tuned for its specific role, which is why dividing primary and secondary fuel flow is essential.