A mid-turbine frame (MTF), and particularly a turning mid-turbine frame (TMTF) is positioned between a high pressure turbine stage and a low pressure turbine stage of a gas turbine engine. The MTF supports multiple bearings and transfers bearing loads from an inner portion of the gas turbine engine to an outer engine frame.
The MTF also serves to route air from a high pressure compressor to one or both of a high pressure turbine stage and a low pressure turbine stage. Existing MTF designs route air through a purge air section of the MTF, causing the air to become heated via exposure to a gas path passing through the MTF.
When the air exiting the MTF and entering the turbine stages is an excessively high temperature, turbine components, such as rotor discs and rotor blades, can have a reduced lifespan. The reduced lifespan can result in increased maintenance frequency, increased maintenance costs, and increased manufacturing costs when higher lifespan components are used.