Robust insulated fuel injector for a gas turbine engine

Abstract

A fuel injector for a combustor of a gas turbine engine is disclosed. The fuel injector includes a flange, a fitting boss, a stem, a gas fuel passage, a gas fuel fitting, and a gas heat shield. The fitting boss protrudes from the flange. The stem extends from the flange. The gas fuel passage extends through the stem. The gas fuel fitting is joined to the fitting boss. The gas heat shield extends from the gas fuel fitting at least partially through the gas fuel passage. The gas heat shield is sized to form a gas heat shield gap between the gas heat shield and the stem at the gas fuel passage.

What is claimed is: 
     
         1 . A fuel injector for a combustor of a gas turbine engine, the fuel injector comprising:
 a flange including mounting holes;   a fitting boss protruding from the flange;   a stem extending from the flange in a direction opposite the fitting boss;   a gallery portion at an end of the stem distal to the flange;   a gas fuel passage extending from the fitting boss to the gallery portion through the stem;   a gas fuel fitting joined to the fitting boss at the gas fuel passage;   a gas heat shield in fluid communication with the gas fuel fitting and extending from the gas fuel fitting at least partially through the gas fuel passage, the gas heat shield being sized to form a gas heat shield gap between the gas heat shield and the stem in the gas fuel passage, the gas heat shield gap; and   a barrel assembly joined to the gallery portion, the barrel assembly being in fluid communication with the gas heat shield.   
     
     
         2 . The fuel injector of  claim 1 , wherein the gas fuel passage has a horizontal cylindrical segment shape and the gas heat shield has a hollow horizontal cylindrical segment shape. 
     
     
         3 . The fuel injector of  claim 1 , wherein the gas heat shield gap is from 5 mils to 15 mils. 
     
     
         4 . The fuel injector of  claim 1 , wherein the gas heat shield gap is not in fluid communication with the gas heat shield. 
     
     
         5 . The fuel injector of  claim 1 , wherein the gas heat shield is metallurgically bonded to the gas fuel fitting. 
     
     
         6 . The fuel injector of  claim 1 , wherein the gas heat shield is from 65 to 85 percent of a length of the gas fuel passage. 
     
     
         7 . The fuel injector of  claim 1 , wherein the gas heat shield is from 70 to 80 percent of a length of the gas fuel passage. 
     
     
         8 . A fuel injector for a combustor of a gas turbine engine, the fuel injector comprising:
 a flange including mounting holes;   a fitting boss protruding from the flange;   a stem extending from the flange in a direction opposite the fitting boss;   a gallery portion at an end of the stem distal to the flange;   a liquid fuel passage extending from the fitting boss to the gallery portion through the stem;   a cap joined to the fitting boss at the liquid fuel passage;   a liquid heat shield extending from the cap towards the gallery portion within the liquid fuel passage, the liquid heat shield being sized to form a liquid heat shield gap between the liquid heat shield and the stem at the liquid fuel passage; and   a barrel assembly joined to the gallery portion, the barrel assembly being in fluid communication with the liquid heat shield.   
     
     
         9 . The fuel injector of  claim 8 , wherein the liquid fuel passage has a right circular cylinder shape and the liquid heat shield has a hollow cylinder shape. 
     
     
         10 . The fuel injector of  claim 8 , wherein the liquid heat shield gap is from 5 mils to 15 mils. 
     
     
         11 . The fuel injector of  claim 8 , wherein the liquid heat shield gap is not in fluid communication with the liquid heat shield. 
     
     
         12 . The fuel injector of  claim 8 , wherein the liquid heat shield is metallurgically bonded to the cap. 
     
     
         13 . The fuel injector of  claim 12 , wherein the liquid heat shield extends to the gallery portion. 
     
     
         14 . The fuel injector of  claim 8 , further comprising:
 a gas fuel passage extending from the fitting boss to the gallery portion through the stem;   a gas fuel fitting joined to the fitting boss at the gas fuel passage; and   a gas heat shield extending from the gas fuel fitting at least partially through the gas fuel passage, the gas heat shield being sized to form a gas heat shield gap between the gas heat shield and the stem at the gas fuel passage.   
     
     
         15 . A dual fuel injector for a combustor of a gas turbine engine, the dual fuel injector comprising:
 a flange including mounting holes;   a fitting boss protruding from the flange;   a stem extending from the flange in a direction opposite the fitting boss;   a gallery portion at an end of the stem distal to the flange, the gallery portion including a first hollow cylinder shape;   a liquid fuel passage extending from the fitting boss to the gallery portion through the stem;   a gas fuel passage extending from the fitting boss to the gallery portion through the stem, wherein at least one of the liquid fuel passage and the gas fuel passage is non-symmetrically located within the stem;   a cap joined to the fitting boss at the liquid fuel passage;   a gas fuel fitting joined to the fitting boss at the gas fuel passage;   a liquid heat shield extending within the liquid fuel passage, the liquid heat shield including a first liquid heat shield end joined to the cap and a second liquid heat shield end adjacent the gallery portion;   a gas heat shield extending within the gas fuel passage, the gas heat shield including a first gas heat shield end joined to the gas fuel fitting and a second gas heat shield end distal to the gas fuel fitting; and   a barrel assembly joined to the gallery portion.   
     
     
         16 . The dual fuel injector of  claim 15 , wherein the liquid heat shield is sized to form a liquid heat shield gap from 5 to 15 mils between the liquid heat shield and the stem at the liquid fuel passage, and the gas heat shield is sized to form a gas heat shield gap from 5 to 15 mils between the gas heat shield and the stem at the gas fuel passage. 
     
     
         17 . The dual fuel injector of  claim 15 , wherein the gas heat shield is metallurgically bonded to the gas fuel fitting. 
     
     
         18 . The dual fuel injector of  claim 15 , wherein the liquid heat shield is metallurgically bonded to the cap. 
     
     
         19 . The dual fuel injector of  claim 15 , wherein the gas heat shield is from 65 to 85 percent of a length of the gas fuel passage. 
     
     
         20 . The dual fuel injector of  claim 15 , wherein the gas fuel passage has a horizontal cylindrical segment shape and the gas heat shield has a hollow horizontal cylindrical segment shape.