Cooled purging fuel injectors

摘要

A fuel injector includes a main fuel nozzle (59) with a main nozzle fuel circuit and a pilot nozzle fuel circuit in fuel supply communication with a pilot nozzle (58). The injector further includes a purge means (216) for purging the main nozzle fuel circuit while the pilot nozzle fuel circuit supplies fuel to the pilot nozzle (58) and a purge air cooling means (340) for supplying a cooled portion (342) of purge air to the main nozzle fuel circuit during purging. The cooled portion (342) is cooled with fuel that flows through the pilot nozzle fuel circuit. The purge air cooling means (340) may include a purge air cooling path (344) in thermal conductive communication with the pilot nozzle fuel circuit and operable to flow the cooled portion (342) therethrough to the main nozzle fuel circuit during purging. The purge air cooling path (344) may be in thermal conductive communication with at least one annular pilot leg of the pilot nozzle fuel circuit.