What is the purpose of a duplex fuel nozzle?

The purpose of a duplex fuel nozzle is to provide two discharge spray patterns. In jet engines, this design allows for better atomization of the fuel, which helps optimize the combustion process. By having two spray patterns, the nozzle can adjust the fuel delivery based on the engine's operational conditions, such as varying power settings or altitude changes. This enhances fuel efficiency and performance, ensuring more complete combustion and reducing emissions.

The other options do not accurately describe the specific function of a duplex fuel nozzle. For example, while the mixing of fuel and air is an important process in combustion, it is not the primary purpose of a duplex fuel nozzle. Similarly, measuring fuel quantity and preventing fuel vapor lock pertain to different components and mechanisms within fuel systems, rather than the role of the nozzle itself.