Patent ID: 6981841

Claim:
A turbofan engine comprising: a first fan, a second fan, and a multistage compressor joined in serial flow communication for pressurizing air; a combustor disposed at a discharge end of said compressor for mixing fuel with said pressurized air to form combustion gases; a first turbine following said combustor and joined by a first shaft to said compressor; a second turbine following said first turbine and joined to said second fan by a second shaft; a third turbine following said second turbine and joined to said first fan by a third shaft; a first cooling circuit joined to an intermediate stage of said compressor for channeling first-pressure air through the center of said first turbine; a second cooling circuit joined to another intermediate stage of said compressor for channeling second-pressure air to the aft side of said first turbine; a third cooling circuit joined to said discharge end of said compressor for channeling third-pressure air to the forward side of said first turbine; and wherein said first, second, and third cooling circuits are joined to sequential stages of said compressor for extracting therefrom said first-pressure air, said second-pressure air, and said third-pressure air at correspondingly increasing pressure and temperature.