US Patent 6929445 Split flow turbine nozzle

A turbine nozzle includes a hollow vane having opposite pressure and suction sides extending in span between outer and inner bands. The vane includes a forward flow channel behind the leading edge, an aft flow channel in front of the trailing edge, and a middle flow channel disposed therebetween. The three flow channels are disposed in flow communication with an outer plenum outside the outer band for receiving cooling air therefrom. The forward and middle channels are also disposed in flow communication with an inner plenum below the inner band for discharging the air. The aft channel discharges air through the inner band outside the inner plenum in split flow at different pressures.