GB1437617A - Gas turbine - Google Patents

Abstract

1437617 Gas turbine rotor blades - cooling GENERAL ELECTRIC CO 16 Aug 1973 [1 Sept 1972] 38822/73 Heading FIT The invention relates to a gas turbine rotor and blade assembly in which the blades are formed with passages for flow of liquid coolant, means being provided for discharge of the coolant from the blades whereby it may impart a useful torque on the blades. The blade shown in Fig. 1 comprises a core portion 12 and an outer skin 11, the core being formed with a series of longitudinallyextending grooves 13a whereby a series of coolant passages 13 are formed between the core and the skin. Each blade carries a blade platform at its inner end and a shroud portion 16 at its outer end. Manifold grooves 17, 17a are formed adjacent the shroud 16 and passages 21, 21a extend from the manifolds to a chamber 22 formed in the shroud, a convergent-divergent discharge nozzle 23, 24, 26 extending from the chamber. The discharge nozzle is aligned with an opening 18 formed in the stator casing 19. Thus coolant liquid supplied at the inner ends of the passages 13 flows radially outwardly therethrough, thence through the manifolds 17, 17a to discharge through the nozzle 26 into the discharge passage 18, the liquid exerting tangential thrust, also radial inward force on the blade. The shroud is formed with seal ribs 28, 29 and coolant liquid discharging from the passages 13b, 13c adjacent the leading and trailing edges of the blade acts as sealing fluid as it discharges past the seal ribs. The blade root comprises a series of tines 31 which are received in circumferential grooves 34 formed at the periphery of the rotor disc 33, the disc being formed with inwardly facing annular grooves 41, 41a to which coolant liquid is supplied and from which it passes through bores 43, 43a to passages 38 formed on the inner surface of the platform 37, the liquid flowing from the passages 38 to the blade passages 13. In Fig. 4 no blade shroud is fitted, there being manifold grooves 51, 5 1a formed adjacent the blade tip, the coolant passages 13 opening into the grooves; the groove 5 1a connects with the groove 51 at 52 and the groove 51 then opens to a convergent-divergent coolant discharge nozzle 53 which opens at the blade trailing edge. Coolant discharges from the nozzle to a passage 54 formed in the stator casing, the discharge comprising tangential and axial components.