GAS TURBINE ENGINE WITH ROTOR CENTERING COOLING SYSTEM IN AN EXHAUST DIFFUSER

摘要

A gas turbine engine (10) having a rotor centering cooling system (12) for cooling struts (14) within an exhaust diffuser (16) and turbine case to reduce tip rub during hot restarts is disclosed. In particular, the rotor centering cooling system (12) may be positioned within struts (14) in the exhaust diffuser (16) downstream from a turbine assembly (18) for limiting thermal gradients between top and bottom struts (20) to prevent the exhaust bearing body (24) from becoming off-center during steady state operation as a result of the top struts (20) becoming hotter than the bottom struts. The rotor centering cooling system (12) may reduce the temperature at the exhaust diffuser (16) and turbine case, thereby reducing the thermal gradient between the top and bottom struts (20, 22) and top and bottom (28, 32) of the turbine case. As such, the exhaust bearing body (24) remains centered, thereby preventing a tighter blade tip clearance at the top (28) of the turbine assembly (18) than at the bottom (28) of the assembly (18).