Modulated flow turbine nozzle

A gas turbine engine comprising:

• a compressor joined to a turbine for being powered thereby;
• said turbine including a nozzle having a row of hollow vanes extending radially between outer and inner bands;
• each of said vanes having an internal cooling plenum, and a bypass tube extending through said outer and inner bands;
• a first manifold surrounding said outer band and disposed in flow communication with said plenums of said vanes;
• a second manifold surrounding said first manifold and disposed in flow communication with said bypass tubes of said vanes;
• a bleed circuit disposed in flow communication between said compressor and first and second manifolds for channeling pressurized air therebetween;
• and
• a control valve disposed between said bleed circuit and first manifold for modulating flow of said pressurized air into said vane plenums.

A method of cooling a turbine nozzle in a gas turbine engine having a row of hollow nozzle vanes extending radially between outer and inner bands and disposed axially between first and second turbine rotor disks comprising:

• channeling pressurized purge air from a compressor in said engine radially through said vanes to purge forward and aft cavities located between said nozzle inner band and said first and second disks, respectively;
• channeling pressurized cooling air from said compressor and inside said vanes to cool said vanes independently from said purge air;
• and
• modulating flowrate of said cooling air inside said vanes without modulating flowrate of said purge air through said vanes.