Fuel injector nozzles for gas turbine engines

A nozzle comprising:

• an inlet at an upstream end of the nozzle;
• a discharge outlet at a downstream end of the nozzle;
• an first annular wall bounding one side of a fuel passage extending between the inlet and the discharge outlet along a length thereof, whereby such wall is in heat transfer relation with fluid passing through the fuel passage;
• a second annular wall radially spaced from the first annular wall and interposed between the first annular wall and ambient conditions, the second and first walls having downstream tip ends that are relatively longitudinally movable at an interface;
• an internal insulating gap interposed between the first and second walls to insulate the first wall from ambient temperature conditions exterior to the nozzle;
• and
• an annular bellows internal to the nozzle and located in the insulating gap, the bellows having an upstream end sealingly attached to an upstream portion of one of the first and second walls, and a downstream end sealingly attached to a downstream portion of the other of the first and second wall to fluidly separate a thereby isolated portion of the insulating gap from any ambient fluid entering into the gap through the interface.