초록 ▼

A turbine airfoil of a gas turbine engine, the airfoil constructed from a spar and shell, in which the spar includes a root with a plurality of spar cooling air supply channels extending toward the tip and having impingement holes formed along the spar to provide impingement cooling to the shell, an

A turbine airfoil of a gas turbine engine, the airfoil constructed from a spar and shell, in which the spar includes a root with a plurality of spar cooling air supply channels extending toward the tip and having impingement holes formed along the spar to provide impingement cooling to the shell, and the shell includes a plurality of shell return channels extending from the tip toward the root to channel the impingement cooling air to collector cavities located in the root. With a plurality of spar supply channels and shell return channels, a serpentine flow cooling circuit with multi-impingement cooling of the shell is produced. The cooling air supplied to the spar is discharged out exit holes in the trailing edge in one embodiment, or out exit holes and leading edge film cooling holes in a second embodiment. The spar and shell are bonded together using a low pressure and high temperature bonding process that includes thin sheets containing boron. The bonds are formed between the platforms and the joints between the return channels and the supply channels.

대표청구항 ▼

What is claimed is: 1. A turbine airfoil for use in a gas turbine engine, the turbine airfoil comprising: a spar forming a rigid structure to support the airfoil; a shell forming the airfoil surface with a leading edge and a trailing edge, and a pressure side and a suction side; the spar including

What is claimed is: 1. A turbine airfoil for use in a gas turbine engine, the turbine airfoil comprising: a spar forming a rigid structure to support the airfoil; a shell forming the airfoil surface with a leading edge and a trailing edge, and a pressure side and a suction side; the spar including a cooling air supply channel extending from the root and through most of the shell; and, the shell including a cooling air return channel extending to the root and in fluid communication with the cooling air supply channel; and, the spar includes three spar cooling air supply channels and the shell includes two cooling air return channels. 2. The turbine airfoil of claim 1, and further comprising: the spar supply channels and the shell return channels forming a five pass serpentine flow cooling circuit in which the first leg is the spar channel in the leading edge of the airfoil. 3. The turbine airfoil of claim 2, and further comprising: the shell includes a plurality of exit holes along the trailing edge. 4. The turbine airfoil of claim 2, and further comprising: the airfoil includes a root with a cooling supply cavity connected the first spar channel, a first collector cavity connecting the first shell return channel to the second spar supply channel, and a second collector cavity connecting the second shell return channel to the third spar supply channel. 5. The turbine airfoil of claim 1, and further comprising: the spar supply channels and the shell return channels two parallel three pass serpentine flow circuits in which the middle spar supply channel forms the first leg for both of the two serpentine flow circuits. 6. The turbine airfoil of claim 5, and further comprising: the shell includes a plurality of exit holes along the trailing edge and a plurality of film cooling holes along the leading edge. 7. The turbine airfoil of claim 5, and further comprising: the airfoil includes a root with a cooling supply cavity connected the second spar channel, a first collector cavity connecting the first shell return channel to the first spar supply channel, and a second collector cavity connecting the second shell return channel to the third spar supply channel. 8. The turbine airfoil of claim 1, and further comprising: the shell includes a crossover duct to connect the spar supply channel to the shell return channel. 9. The turbine airfoil of claim 1, and further comprising: the spar supply channels each include a plurality of impingement cooling holes to provide impingement cooling air for the shell. 10. The turbine airfoil of claim 9, and further comprising: The spar supply channels include blade tip impingement cooling holes on the ends of the spar channels to provide cooling for the shell tip. 11. The turbine airfoil of claim 1, and further comprising: the shell is bonded to the spar by a thin sheet. 12. The turbine airfoil of claim 1, and further comprising: a bond formed between the spar and the shell to hold the shell to the spar during operation. 13. The turbine airfoil of claim 12, and further comprising: the bond is formed between the cooling air supply channel on the spar and the cooling air return channel on the shell. 14. The turbine airfoil of claim 13, and further comprising: the bond also is formed between the platforms on the spar and the shell. 15. The turbine airfoil of claim 12, and further comprising: the bond is a high temperature and low pressure bond so that the bonding parts do not displace. 16. A process for cooling a turbine airfoil having a spar and shell construction, the process comprising the steps of: channeling cooling air through a first spar supply channel; passing the cooling air through impingement holes to provide impingement cooling to the backside of the shell; directing the impingement cooling air into a shell return channel; and, passing the impingement cooling air through the shell return channel; collecting the cooling air from the shell return channel into a collecting cavity; passing the collected cooling air through a second spar supply channel; and, passing the cooling air through impingement holes in the second spar supply channel to provide impingement cooling to the backside of the shell. 17. The process for cooling a turbine airfoil of claim 16, and further comprising the steps of: collecting the impingement cooling air downstream from the second spar supply channel; and, discharging the cooling air through a series of exit holes in the trailing edge of the shell. 18. The process for cooling a turbine airfoil of claim 16, and further comprising the step of: impingement cooling the shell tip with a portion of the cooling air passing through the first spar supply channel.