Patent GB-1345884-A (GB)
Title: Gas turbine installations
IPC: F02C6/20
Filed: 1971-06-02
Abstract: 1345884 Gas turbine plant DAIMLER-BENZ AG 2 June 1971 [3 June 1970] 18660/71 Heading F1G The invention relates to a gas turbine engine comprising an LP compressor, an HP compressor, a heat exchanger, a combustion chamber, a compressor-drive turbine and a power turbine with reduction gearing, in which the rotary units are divided into at least two groups the axes of which are parallel to one another. The engine shown in Fig.1 comprises an axial flow LP compressor 1, a radial-flow HP compressor 2 and a compressor-drive turbine 5 all disposed on one axis 18, a heat exchanger 3, combustion equipment 4 disposed on a second axis 20 parallel to the axis 18, and a power turbine 6 disposed on a third axis 19 parallel to the two axes 18, 20. The power turbine 6 drives an output shaft 9 through reduction gearing indicated. The engine is provided with means whereby it may be operated in series flow or parallel flow, the means comprising change-over members indicated at 10 and 14. In series flow operation air enters the LP compressor 1 through inlet 12 and discharges to the HP compressor 2 from which it discharges to the heat exchanger 3. After preheating, the air passes to the combustion equipment, gases from which pass to the compressor-drive turbine 5, the gases then passing to the power turbine 6 from which they discharge through the heat exchanger 3 to atmosphere. In the parallel-flow mode of operation air passes into the LP compressor 1, also directly to the compressor 2; air delivered by the two compressor passes in parallel to the heat exchanger and then to the combustion equipment. Gases from the combustion equipment flow in parallel to the compressor drive turbine 5 and to the power turbine 6, the gases discharging from the two turbines passing to the heat exchanger 3. In Fig.3 the axial-flow LP compressor 32 and the radial flow HP compressor 33 are mounted on one axis 35 and the combustion equipment 39, the compressor drive turbine 36 and the power turbine 37 are mounted on a second axis 40 disposed below and parallel to the axis 35, the compressor-drive turbine driving the compressors 32, 33 through gearing. The heat exchanger comprises a pair of headers 75 each disposed at one side of the engine with its axis parallel to the axes 35, 40 and the tubes 73 extending substantially vertically, see Figs.4, 5, 6, 7. The engine is arranged for series flow and parallel flow operation and for this comprises change-over devices 34 and 38. In the series flow mode of operation air enters the LP compressor 32 and then passes to the HP compressor 33 discharging therefrom through ducts 43 to the inlet manifolds 75 of the heat exchanger, see Figs.6 and 7. After preheating, the air passes to the combustion equipment 39, the gases from which pass through outlet 47 to the compressor-drive turbine 36, the gases then passing to the power turbine 37, the exhaust gases discharging through ducts 50 and across the tubes 73 of the heat exchanger. In the parallel flow mode of operation air enters the compressor 32 and also through inlet 45 the compressor 33, air from the two compressors discharging through ducts 44, 43 to the heat exchanger inlet manifolds 75. The preheated air passes to the combustion chamber 39, gas discharging therefrom through outlet 47 to the  compressor-drive turbine 36 discharging therefrom through duct 46 to flow across the heat exchanger tubes 73; gas also discharges from the combustion chamber through outlet 48 directly to the power turbine 37 the gases discharging therefrom through outlet 50 to flow across the tubes 73 of the heat exchanger.