Patent ID: 8584469

Claim:
A gas turbine engine comprising: a supply of cooling fluid; a rotatable shaft; shaft cover structure; blade disc structure coupled to said shaft having at least one bore for receiving cooling fluid; a pre-swirl structure disposed about said shaft, said pre-swirl structure comprising: radially inner wall structure coupled to said shaft cover structure, said inner wall structure extending about said shaft; radially outer wall structure spaced from said inner wall structure, said outer wall structure coupled to said shaft cover structure and extending about said shaft, said inner and outer wall structures defining a flow passage therebetween, said flow passage including an inlet and an outlet and receiving a first portion of cooling fluid from said supply of cooling fluid; and a plurality of swirl members extending in said flow passage between said inner and outer wall structures, said swirl members each including a leading edge at said flow passage inlet and a trailing edge at said flow passage outlet and offset from said leading edge in the circumferential direction; a plurality of bypass passages associated with said shaft cover structure, said bypass passages in fluid communication with said supply of cooling fluid for supplying a second portion of cooling fluid from said supply of cooling fluid to a turbine rim cavity defined between said blade disc structure and an upstream stator support structure, said plurality of bypass passages including a first set of bypass passages and a second set of bypass passages, the first and second sets of bypass passages having inlets that are located respectively in separate chambers of the gas turbine engine and in different radial locations; and a static metering structure associated with an outlet of each said bypass passage, said metering structure comprising at least one flow passageway formed therein for permitting the second portion of cooling fluid in each said bypass passage to pass into the turbine rim cavity; wherein said supply of cooling fluid supplies the first portion of cooling fluid to said pre-swirl structure such that the cooling fluid exiting said flow passage outlet has a velocity component in a direction tangential to the circumferential direction; wherein a swirl ratio defined as the velocity component in the direction tangential to the circumferential direction of the first portion of cooling fluid to a velocity component of said shaft in the direction tangential to the circumferential direction is greater than one as the cooling fluid exits said flow passage outlet and the swirl ratio is about one as the first portion of cooling fluid enters said at least one bore formed in said blade disc structure; and wherein an annular cavity extends between said flow passage outlet and said at least one bore formed in said blade disc structure.