Patent GB-666062-A (GB)
Title: Gas turbine power plant
IPC: F02K3/11
Filed: 1948-01-16
Abstract: 666,062. Gas turbine plant. LYSHOLM, A. Jan. 16, 1948 [Feb. 28, 1947; Feb. 28, 1947], Nos. 1434/48, and 1435/48. [A Specification was laid open to inspection under Sect. 91 of the Acts, July 19, 1948.] Class 110 (iii). [Also in Groups XI and XXXIII] In an aircraft jet propulsion engine having two jet propulsion aggregates, a main aggregate comprising a compressor, a combustion chamber, a gas turbine driving the compressor and a jet nozzle and a supplementary aggregate comprising a compressor, a combustion chamber and a jet nozzle separate from the jet nozzle of the main aggregate, the supplementary compressor being driven from the main aggregate and arranged so that the inlet thereof is located within the radial confines of the complete jet propulsion engine, the area of the jet nozzle of the supplementary aggregate is made variable. The plant shown has two compressors, namely, a single stage compressor 1 and a two stage centrifugal compressor 2, 3. The compressor 1, provided with adjustable inlet guide vanes 5, discharges through a plurality of conduits 6 into a combustion chamber 7 which exhausts through an annular nozzle 8. The compression ratio of the compressor 1 should be at least 1À5 and preferably be 2À0 and 2À5. The compressor 2, 3 sucks air through an annular opening 10 and discharges it through the combustion chamber 16, the turbine 19, the annular exhaust nozzle 20 and the propulsion nozzle 21. The passage between the opening 10 and the guide vanes 12 crosses the discharge conduits 6 from the compressor 1. The area of the nozzle 21 can be adjusted by the member 22 and that of the nozzle 8 by flaps 27 controlling the additional discharge openings 26. To control the operating conditions of the plant, air bleed openings 35, 36 are provided. The openings 35, which face rearwardly, increase the propulsion effect and at the same time blow off the boundary layer. The openings 36, which are controlled by flaps, are forwardly directed so that they may be used to brake the aircraft. A fan 53, which sucks air through the slot 54 and discharges it through conduits 30 is provided to reduce the boundary layer on the nacelle. The combustion chamber 16 is provided with an annular V-shaped screen or baffle 37 so as to divide the compressed air into two streams. One stream passes radially inwards through the slot 38 whilst the other stream flows axially through the passage 39 and is discharged into the chamber through the opening 42. Part of the second stream enters the chamber through the slot 43. The shape of the combustion chamber and the location of the air inlet openings, cause a turbulent zone behind the baffle 37 into which fuel is injected through a pipe 44. To reduce losses, the air inlet and gas outlet are arranged at the same axial end of the chamber. A substantial part of the air passing through the slot 38 passes direct to the turbine and cools the inner ends of the blades. The combustion chamber 7 is of similar construction to the combustion chamber 16. The air from the conduits 6 is divided into three streams. One stream passes radially inwards through a passage 45, a second stream enters the combustion chamber through an annular 47 and the third stream enters the chamber through an annular slot 48. The stream passing through the passage 45 enters a passage between the exhaust passage 20 and an internal wall 49. A part of this stream is deflected into the combustion chamber by a U-shaped deflector 52. Fuel is injected through a pipe 51 into a turbulent region behind the annular screen 50. A part of the third stream of air passes direct to atmosphere through the annular slot 55 after passing through the passage formed between the internal wall 46 and the engine casing Specification 583,111 is referred to. The Specification as open to inspection under Sect. 91 comprises also a modification in which the compressor wheel 1 is dispensed with and the wheel 2 provided with a partition so as to form two passages, one of which feeds air direct to the reheat chamber and the other feeds to the second stage 3. This subject-matter does not appear in the Specification as accepted.