GB946959A - Improvements in or relating to plant including a pressure exchanger and a gas turbine - Google Patents

Abstract

946,959. Gas turbine plant; pressure exchangers. POWER JETS (RESEARCH AND DEVELOPMENT) Ltd. Sept. 6, 1962 [Sept. 7, 1961], No. 32116/61. Headings FIG and FIN. In a plant which includes a gas turbine, a pressure exchanger and a combustion chamber, the outlet of the latter communicates through ducting with the pressure exchanger and the gas turbine and the ducting communicating with the turbine is surrounded, at least in part, by a casing communicating with a source of fluid at a temperature lower than the temperature of the combustion gases, and apertures in that part of the ducting within the casing serve to admit fluid from the casing whereby the combustion gases can be rendered acceptable to the gas turbine. Compressed air from the outlet 19 of a pressure exchanger flows through a conduit 33, the cold pass 34 of a heat exchanger 35 and a conduit 36 to a reverseflow combustion chamber 37. The resulting hot gases pass through a conduit 40 to a volute 41 where they split to supply a two-stage high-speed turbine 42, provided with a reduction gear 49, and an inlet conduit 27 of the pressure exchanger. Some of the air bypasses the heat exchanger 35 through a conduit 47 into a casing 43, 44 surrounding the volute 41. This air, which is substantially at the same pressure as, but is cooler than, the hot gases, passes through apertures 48A into the hot gases to cool the latter and also to balance the pressure in the volute 41 and conduit 27. Instead of apertures 48A slots may be provided which are so directed as to produce a layer of cooler air at the tips and roots of the turbine blades. The rotor of the pressure exchanger is provided with outer and inner cell rings 1 and 2, and is secured to stub-shafts 11 supported in bearings 12 carried by end members 13 and 14 extending from which are ducts associated with cells 3 and 4 of rings 1 and 2. Fig. 2 shows a developed view of the pressure exchanger, the cells 4 and associated ducts being represented by chain lines. A fan 17A, which may be driven by an extension of the rotor shaft, supplies air to the cells 3 through the pressure exchanger inlet 17, which inlet may be a cylindrical duct of the same diameter as the rotor. The rotor rotates in the direction of arrow 50 and when a cell 3 overlaps conduit 21, intermediate pressure gas compresses the air into conduit 29, the gas in the cell 3 eventually being exhausted through conduit 25 to join with the exhaust gases from the turbine 42 and pass through the hot pass 38 of the heat exchanger 35. The intermediate pressure air in conduit 29 passes through conduit 31 to one of the cells 4, and when the cell overlaps conduit 27 high pressure gas from the combustion chamber 37 compresses the air through the outlet 19, the gas in the cell 4 eventually being transferred to an intermediate pressure gas inlet conduit 23. The ends of the cell walls in either or both rings 1 and 2 are curved (not shown) in the manner of a turbine blade so that the rotor is self-driving. The rotor speed is controlled in accordance with the throttle setting of the turbine by arranging the rotor to develop surplus power which is absorbed by a friction brake governor, the speed selector of which is connected to the throttle. According to the Provisional Specification the outer casing 15 of the pressure exchanger is formed of two mutually telescoping tubes which facilitate thermal expansion.