Simple low cost fuel nozzle support

摘要

The invention relates to a simple low cost fuel nozzle support stem that can be manufactured to meet extremely close tolerances with enhanced structural rigidity through use of a cylindrical stem body machined from solid bar stock. Superior thermal control to regulate thermal displacement of the stem body and to prevent fuel coking is provided by a concentric secondary fuel bore and a primary fuel tube disposed within the bore. The low pressure secondary fuel flow encircles the high pressure primary flow tube and serves to cool the fuel tube and cylindrical stem body in a uniform symmetric manner. An outer cylindrical insulating sleeve mounted on shoulders extending from the cylindrical body of the stem defines an elongate annular insulating air gap between the sleeve and cylindrical stem body. The support stem includes a dual fuel spray nozzle and a fuel adapter/mounting flange that are mounted to the stem body with simple cylindrical sockets. Therefore, the support stem has a modular construction based on a simple cylindrical easily machined stem body with concentric primary and secondary fuel channels, a fuel adapter/mounting flange with cylindrical socket brazed to an outer end of the stem body, and a replaceable nozzle with cylindrical socket brazed to an inner end of the stem body.