Turbine blade composite cooling circuit

Claim 1

A gas turbine engine blade comprising: an airfoil having opposite first and second sides joined together at leading and trailing edges, and extending radially from a root to a tip; a serpentine cooling circuit disposed in said airfoil and having a first leg extending from said root toward said tip for channeling cooling air outwardly therethrough, a first reverse bend disposed adjacent to said tip in flow communication with said first leg for redirecting said cooing air therefrom inwardly from said tip toward said root, and a second leg extending inwardly and disposed in flow communication with said first reverse bend for channeling said cooling air inwardly therefrom; a discrete branch cooling circuit disposed in said airfoil adjacent to said serpentine circuit and extending radially from said root to said tip; a plurality of branch metering orifices disposed in flow communication with said serpentine circuit for channeling therefrom to said branch circuit in parallel flow a portion of said cooling air channeled through said serpentine circuit; a plurality of branch discharge holes disposed in flow communication with said branch circuit and extending through said airfoil first side for discharging said cooling air portion from said branch circuit for film cooling said airfoil first side; a plurality of discharge holes for said serpentine circuit disposed in flow communication with said serpentine circuit and extending through said airfoil second side for discharging said cooling air from said serpentine circuit for film cooling said airfoil second side; and wherein said branch metering holes are effective for independently controlling discharge of said cooling air portion from said branch discharge holes on said airfoil first side relative to discharge of said cooling air from said serpentine discharge holes on said airfoil second side.