A small and medium-sized gas
turbine power turbine rotor air
system relates to the technical field of
gas turbines. The problems that an existing gas
turbine with a
power turbine needs to
bleed air from different positions of an
air compressor, so that the using amount of cooling air is large, and the
cooling efficiency is low are solved. The gas
turbine comprises a front wall, a main flow gas channel, a first-stage
turbine wheel disc, a rear wall and a shaft cavity, a first cavity is formed between the first-stage
turbine wheel disc and the front wall, the first cavity and the shaft cavity communicate with a
gas compressor at the same time, and the first cavity communicates with the main flow gas channel through a first gas outlet, a second gas outlet and a third gas outlet; only one strand of
compressed air is led out from a certain part of the
air compressor, one part of the
compressed air flows into the first cavity, the other part of the
compressed air flows into the shaft cavity and converges into the mainstream
fuel gas channel after passing through the multi-stage blades, and the compressed air is shunted, so that the effects of cooling the wheel disc, sealing the disc cavity and sealing and pressurizing the bearing cavity can be completed, and the
cold air consumption can be saved; the gas turbine unit efficiency is improved.