Cast steel frame for gas turbine engine

Abstract

A gas turbine engine comprises a first turbine module, a second turbine module, and a frame interconnecting the first turbine module with the second turbine module. The frame includes a plurality of circumferentially distributed struts extending radially between an inner hub and an outer case, and is formed from a single steel sand casting.

1 . A gas turbine engine comprising:
 a first turbine module;   a second turbine module;   a frame interconnecting the first turbine module with the second turbine module, the frame comprising a single, unified steel casting which includes a plurality of circumferentially distributed struts extending radially between an inner hub and an outer case.   
     
     
         2 . The engine of  claim 1 , wherein the single unified steel casting has a minimum radial dimension measuring at least about 60 inches (about 1.5 meters). 
     
     
         3 . The engine of  claim 1 , wherein the single unified steel casting has a minimum radial dimension measuring at least about 80 inches (about 2.1 meters). 
     
     
         4 . The engine of  claim 1 , wherein the frame includes a radially extending cooling passage formed through each of the plurality of struts. 
     
     
         5 . The engine of  claim 4 , wherein the radially extending cooling passages are machined through solid cast struts. 
     
     
         6 . The engine of  claim 1 , further comprising:
 a fairing assembly including at least one fairing segment secured over a plurality of annular frame surfaces between the inner case and the outer hub, the fairing assembly defining a main gas flow passage through the frame.   
     
     
         7 . The engine of  claim 6 , further comprising:
 a heat shield assembly including at least one heat shield segment disposed between the at least one fairing segment and an annular frame surface.   
     
     
         8 . The engine of  claim 1 , wherein the first module comprises a low pressure turbine module and the second module comprises a power turbine module. 
     
     
         9 . A turbine exhaust case (TEC) assembly for a gas turbine engine, the TEC assembly comprising:
 a frame comprising a single unified steel casting, the frame including a plurality of circumferentially distributed struts extending radially between an inner hub and an outer case; and   a fairing assembly including at least one fairing segment secured over a plurality of annular frame surfaces between the inner case and the outer hub, the fairing assembly defining a main gas flow passage through the frame.   
     
     
         10 . The assembly of  claim 9 , wherein the single unified steel casting has a minimum radial dimension measuring at least about 60 inches (about 1.5 meters). 
     
     
         11 . The assembly of  claim 9 , wherein the single unified steel casting has a minimum radial dimension measuring at least about 80 inches (about 2.1 meters). 
     
     
         12 . The assembly of  claim 9 , wherein the frame includes a ballistically machined cooling passage formed through each of the plurality of struts. 
     
     
         13 . The assembly of  claim 9 , wherein the single unified steel casting comprises at least about 11 wt % chromium and at least about 3 wt % nickel. 
     
     
         14 . A gas turbine engine frame comprising:
 an outer case;   an inner hub; and   a plurality of struts distributed circumferentially around the frame and extending radially between the inner hub and the outer case, the outer case, the inner hub, and the plurality of struts formed as a single unified steel casting.   
     
     
         15 . The frame of  claim 14 , wherein a radial dimension of the frame measures at least about 60 inches (about 1.5 meters). 
     
     
         16 . The frame of  claim 14 , wherein a radial dimension of the frame measures at least about 80 inches (about 2.1 meters). 
     
     
         17 . The frame of  claim 14 , wherein the single steel sand casting includes a plurality of solid cast strut bars. 
     
     
         18 . The frame of  claim 17 , further comprising:
 a radial cooling passage ballistically machined through each of the struts, each passage extending between the outer case and the inner hub.   
     
     
         19 . The frame of  claim 18 , further comprising:
 a cooling hole providing fluid communication between the passage and an outer surface of the strut.   
     
     
         20 . The frame of  claim 14 , wherein the single steel sand casting comprises at least about 11 wt % chromium and at least about 3 wt % nickel.