Patent GB-1340363-A (GB)
Title: Gas turbine power plants
IPC: F02C7/04
Filed: 1971-01-11
Abstract: 1340363 Homopolar machines SOC NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION 11 Jan 1971 [15 Jan 1970] 1160/71 Heading H2A [Also in Division F1] A gas turbine engine comprises a compressor and a turbine, the turbine driving at least one homopolar electrical generator and the compressor being driven by at least one homopolar motor supplied with current from the generator. A number of different homopolar machine constructions are described. First embodiment (Fig. 2).-A number of homopolar motors each driving one stage of a compressor are carried by a stationary shaft structure 5 comprising a centre shaft 11, an intermediate shaft 16 and an outer cylinder 44. The first stage of the compressor comprises blades 120 mounted on a rotor disc 124, 126, 128, the part 128 constituting the armature of a homopolar motor through which current flows axially as indicated by arrow I. The armature is rotatably supported on the shaft 16 by means of films of liquid metal disposed at the surfaces 130, 131, a member 134 being secured on the shaft 16 but electrically insulated therefrom. The films of liquid metal permit the passage of the current I. Superconducting field coils 36, 136 are disposed between the shafts 11 and 16 within a casing 45 having an inlet and outlet 46, 48 for the flow of liquid helium and generate a magnetic flux as indicated by arrows B. The second stage 222 is similar to the first stage except that the magnetic field generated by the field coils 136, 236 flows radially outwardly through the armature 228 whereby the second stage rotates in the opposite direction to the first stage. The remaining compressor stages are similar. Second embodiment (Fig. 3).-A homopolar generating arrangement comprises two rotors 154, 254 driven by respective contra-rotating turbines, as 150, and mounted on the shaft 16 and on a ring member 54 secured on the shaft by means of films, as 161, 162, of liquid metal which allow the flow of current as indicated by arrows I. The superconducting field coils 60, 160, 260, 164, 264 create a magnetic field as indicated by arrows B, and are each disposed within a casing 70 through which liquid helium flows. Third embodiment (Fig. 12).-Rotor members 1124 of a homopolar motor drive a drum 1120 which is rotatably mounted in bearings 1121, 1122 and which supports compressor blades 1119. The stator members 1123 of the motor are mounted on the stationary shaft structure 1128, 1129, 1130, the portion 1130 on which the stator members are mounted being non-conducting. Liquid metal films 1127 are provided between the rotor and stator members and the current flows as indicated by arrows I through the stationary shaft 1129, through the rotor and stator members 1124, 1123, through the stationary shaft 1128 and back through the stationary inner shaft 1111. The field coil which is a superconductor 1125 is mounted on stator structure 1126 and creates a magnetic field as indicated by arrow B. Fourth embodiment (Fig. 13).-Rotor discs 1224 of a homopolar motor carry compressor blades 1219 and are rotatably mounted on a fixed shaft member 1211. Disc members 1223 are fixedly mounted on the shaft and carry superconducting field coils 1225 which generate a magnetic field B; the coils 1225 are disposed within casings 1225a through which liquid helium is circulated. Alternate members 1223 form supports for the rotor discs 1224 by means of rings 1227b of liquid metal which also allow passage of current I. The discs are also supported on the stationary shaft 1211 or central flanges of the dises 1223 by means of rings 1227a of liquid metal. Current flows through the outer stationary shaft member 1212, rotor discs 1224 and stator discs 1223a and 1223b as indicated by arrows I, the current returning through stationary shaft 1211. The stator discs 1223a, 1223b are insulated from the shaft 1211 by a layer of alumina. The current flows in opposite radial directions in adjacent rotor discs and the discs therefore are driven in opposite directions. Fifth embodiment (Fig. 15).-A homopolar generator 14c driven by a compressor supplies power to a homoplar motor 15c driving a fan 1c. The generator comprises a disc 16c connected to an extension 19c of the compressor shaft 20c, the extension being mounted in a bearing 21c. The motor comprises a disc 17c secured to a shaft 23c which is connected at its forward end 22c to the fan rotor 1c; the bearing 25c being supported in fixed structure 27c and the bearing 26c being located within the shaft extension 19c in the plane of the bearing 21c. The field winding 33c is a superconductor.