Thermal gradient dispersing heatshield assembly

Abstract

An airblast fuel nozzle has an injector head with an outer air flow through an outer air flow swirler, an intermediate fuel flow through an intermediate fuel swirler, and an inner air flow through an inner air swirler. A heatshield assembly protects the intermediate fuel swirler from hot air passing through the inner air swirler. The heatshield assembly includes an inner heatshield extending from the inlet end of the fuel swirler to the outlet end of the fuel swirler, and an intermediate heatshield disposed between the inner heatshield and the fuel swirler. According to one embodiment, the inner heatshield is connected, such as by brazing, at its downstream end to the intermediate heatshield, and at its upstream end to the fuel swirler. The upstream connection to the fuel swirler is preferably at or downstream from the midpoint of the fuel swirler. An air gap is provided between the inner heatshield and the intermediate heatshield, and between the intermediate heatshield and the fuel swirler. According to a second embodiment, the intermediate heatshield is connected at its downstream end to the downstream end of the fuel swirler, and at its upstream end to the inner heatshield, at a location at or downstream from the midpoint of the inner heatshield. An air gap is also provided between the inner heatshield and the intermediate heatshield, and between the intermediate heatshield and the fuel swirler. The intermediate heatshield allows axial and radial expansion of the inner heatshield without affecting the fluid flow through the fuel passage or the inner air passage, has reduced stress concentration at the connection point, and has increased cycle life without fatigue failure.

Dependencies are inferred from the claim text.