Patent ID: 8511969

Claim:
A gas turbine engine comprising: a mid turbine frame (MTF) disposed axially between first and second turbine rotors, the MTF including an annular outer case, an annular inner case and a plurality of load spokes radially extending between and interconnecting the outer and inner cases; an annular inter-turbine duct (ITD) disposed radially between the outer and inner case of the MTF, the ITD including an annular outer duct wall and annular inner duct wall, an annular hot gas path between the outer and inner duct walls, and a plurality of hollow airfoils radially extending between and interconnecting the outer and inner duct walls; a first annular cavity defined between the annular outer case and the outer duct wall, and a second annular cavity defined between the annular inner duct wall and the inner case, the first and second cavities in fluid communication with an inner space in the respective hollow airfoils; each of the hollow airfoils including a double-walled leading edge structure, thereby defining a front chamber in the structure separated from a rear chamber defined in a remaining space within the hollow airfoil, the rear chamber of at least a number of the hollow airfoils accommodating one said spoke to pass therethrough; an annular first seal housing disposed in the first cavity, thereby defining an annular outer front cavity between the first seal housing and an upstream section of the outer duct wall, the outer front cavity being separated from the first cavity; and an annular second seal housing disposed in the second cavity, thereby defining an annular inner front cavity between an upstream section of the inner duct wall and the second seal housing, the inner front cavity being separated from the second cavity, the outer and inner front cavities being in fluid communication with the front chamber of the respective airfoils.