Gas turbine engine with rotor centering cooling system in an exhaust diffuser

A gas turbine engine comprising:

• at least one exhaust diffuser positioned downstream from a turbine assembly, extending circumferentially around a central longitudinal axis of the gas turbine engine and having an increasing cross-sectional area from an upstream edge to a downstream edge;
• at least one strut extending from the at least one exhaust diffuser radially inward to an inner exhaust diffuser housing forming a radially inner surface of the exhaust diffuser;
• wherein the at least one strut includes at least one internal cooling system positioned within an outer wall forming the at least one strut;
• and
• a rotor centering cooling system, comprising:
• an exhaust cooling manifold in communication with the at least one internal cooling system positioned within the outer wall forming the at least one strut for supplying cooling fluid to the at least one internal cooling system in the at least one strut;
• at least one rotor centering cooling channel extending from an inlet in the exhaust cooling manifold, through a turbine casing exhaust flange to an outlet in a shroud cavity upstream from the at least one strut and radially outward from an outer wall forming the at least one exhaust diffuser, wherein the cooling fluid flowing through the at least one rotor centering cooling channel entrains ambient air within the shroud cavity, thereby purging the shroud cavity and cooling the turbine casing exhaust flange;
• and
• at least one exhaust cooling plenum forming a circumferentially extending cooling channel radially outward from the outer wall forming the at least one exhaust diffuser and wherein the exhaust cooling plenum is in fluid communication with the exhaust cooling manifold via at least one metering hole,
• wherein the at least one metering hole is positioned within the turbine casing exhaust flange, thereby providing cooling to the turbine casing exhaust flange.