Gas turbine engines

Claim 1

A compact, medium output gas turbine engine, comprising compressor means for compressing inlet air, said compressor means comprising at most three stages, including one centrifugal-type compressor stage, all mounted on a common shaft, at least the final one of said stages being constituted by an axial compressor portion of an integral axial compressor/axial compressor-turbine unit including a turbine disk carrying a row of blades in the form of two concentric arrays of blades the inner array of which constitutes said axial compressor portion and the outer array of which constitutes an axial compressor-turbine portion of said integral axial compressor/axial compressor-turbine unit, combustion means for burning fuel in mixture with the compressed air produced by said compressor means to provide hot gases, output-power generating means located downstream of said combustion means and operated responsive to said hot gases, first means for directing said hot gases from said combustion means to said axial compressor-turbine portion of said integral axial compressor/axial compressor-turbine unit for driving the same and therethrough said axial compressor portion of said integral axial compressor/axial compressor-turbine unit and therewith the preceding stage or stages of said compressor means, second means for directing the compressed air which is produced by said preceding stage or stages of said compressor means to said final stage thereof prior to mixing of that compressed air with fuel, for thereby cooling said row of blades of said integral axial compressor/axial compressor-turbine unit, both said first and second directing means being constructed and arranged for guiding the compressed air and said hot gases to flow solely in the interior of the engine and in the same direction through said integral axial compressor/axial compressor-turbine unit, and heat exchanger means intercalated between said integral axial compressor/axial compressor-turbine unit and said output-power generating means, said integral axial compressor/axial compressor-turbine unit being arranged for direct flow of said compressed air and said hot gases from the respective portions of said unit into said heat exchanger means, said heat exchanger means serving for transferring heat from said hot gases to said compressed air as said hot gases leave said axial compressor-turbine portion of said integral axial compressor/axial compressor-turbine unit and flow therefrom to said output-power generating means and as said compressed air leaves said axial compressor portion of said integral axial compressor/axial compressor-turbine unit and flows therefrom to said combustion means.