Turbine blade tip with tip shelf diffuser holes

摘要

A turbine blade having a tip including a tip shelf through which pass one or more diffuser cooling holes, the diffuser cooling holes directing the flow of cooling gas along the tip shelf, spreading the flow of cooling gas more evenly along the tip shelf and enhancing the formation of a curtain of cooling air along the tip shelf, leading to lower blade tip temperatures, reduced diversion of cooling air, and greater turbine blade life.

主权项

1. A gas turbine engine blade comprising:
an airfoil including a first side joined to a second side at spaced apart leading and trailing edges to define therein a flow channel for channeling cooling air through said airfoil to cool said airfoil from combustion gases flowable over said first side and second side, said airfoil having a tip; said tip comprising: a tip floor extending between said first side and second side and between said leading and trailing edges for enclosing said airfoil for containing said cooling air in said flow channel; a first tip wall extending from said tip floor at said airfoil first side to form an extension thereof; a second tip wall extending from said tip floor at said airfoil second side to form an extension thereof and spaced in part from said first tip wall to define therebetween an outwardly facing tip plenum; said first tip wall being recessed at least in part from said airfoil first side to define an outwardly facing tip shelf extending between said leading and trailing edges to provide a discontinuity in said airfoil first side, said first tip wall and said outwardly facing tip shelf defining therebetween a trough; and a plurality of diffuser cooling holes extending through said tip shelf in flow communication between said flow channel and said trough for channeling a portion of said cooling air into said trough for cooling said tip, wherein said plurality of diffuser cooling holes comprise a diffuser portion comprising a generally conical shape comprising side walls that flare outwardly at an angle relative to a longitudinal axis of said diffuser cooling holes and wherein said plurality of diffuser cooling holes further comprise a generally straight section in flow communication with said flow channel for channeling cooling air and wherein said plurality of diffuser cooling holes comprise a pair of slots in said diffuser portion, one said slot extending along said tip shelf in a substantially forward direction and the other said slot extending along said tip shelf in a substantially aft direction along said tip shelf.