In the marine gas turbine engine shown in the illustration, the HP turbine 2nd stage nozzle vanes are cooled by which of the following? Illustration GT-0020

Correct Answer: Option C — 13th stage compressor air.

Cooling the high-pressure turbine 2nd stage nozzle vanes requires air at a pressure higher than the local gas path pressure. The 13th stage compressor bleed air provides the necessary pressure differential to ensure effective convective cooling, maintaining the nozzle vanes within their safe operating temperature limits.