Patent ID: 8015815

Claim:
A nozzle comprising: an inlet at an upstream end of the nozzle; a discharge outlet at a downstream end of the nozzle; a fluid delivery passage extending between the inlet and the discharge outlet; an internal annular wall bounding one side of the fluid delivery passage along a length thereof, whereby such wall is in heat transfer relation with fluid passing through the fuel delivery passage; an external annular wall interposed between the internal annular wall and ambient conditions, the external and internal walls having downstream tip ends that are relatively longitudinally movable at an interface; and an internal insulating gap interposed between the internal and external walls to insulate the internal wall from ambient temperature conditions external to the nozzle; and wherein one of the internal and external walls has formed therein, proximate the downstream tip ends thereof, at least one labyrinth groove opening toward the other one of the internal and external walls for capturing ambient fluid that may enter into the insulating gap through the interface.