Turbine wheel having internally cooled rim and rated breaking points

A turbine wheel comprising:

• a disc including a central portion and a rim portion around the periphery of said central portion, and blades spaced apart around the periphery of said rim portion,
• b. a plurality of through holes in said disc spaced apart circumferentially, said holes providing communication for cooling air flow between the opposite sides of the turbine wheel,
• c. cooling air flow guide means on each side of the disc, said guide means defining a high pressure chamber on one side of said disc and a low pressure chamber on the opposite side of said disc, both of said chambers communicating with said through holes, and said guide means defining an entry passage through which cooling air can flow into said high pressure chamber and an exit passage through which cooling air can flow out of said low pressure chamber, said entry passage being located radially inwardly of said exit passage, and
• d. a generally tubular baffle in each of said through-holes, said baffle being spaced from the wall of said through-hole along at least a portion of the length of the baffle, said baffle being open at its end facing said high pressure chamber to receive cooling air therefrom, means for preventing flow of air to the other end of the baffle, and a plurality of holes in the wall of the baffle for directing cooling air radially against the wall of the through-hole, said baffles being flared at their opposite ends to maintain a spacing between the remainder of each baffle and its respective through hole wall, and said means for preventing flow of air being a bent tab arranged at the closed end of each baffle, said tab preventing axial movement of said baffle within its respective through hole,
• e. in combination with a stator at one side of the turbine wheel, said stator having a series of passageways through which cooling air flows toward the through holes in the turbine wheel.