GB843278A - Improvements in or relating to fluid machines having bladed rotors - Google Patents

Abstract

843,278. Gas turbine plant. ROLLS-ROYCE Ltd. July 2, 1958 [July 18, 1957], No. 22856/57. Class 110 (3). In a fluid machine having a bladed rotor the blades of which are provided with internal fluid-conveying passages, the inlets of the latter open into a manifold space bounded by the rotor and a plate or ring member carried thereby, and stationary nozzles direct jets of gaseous fluid towards inlet ports formed in the plate or ring member. The blades 17, 20, Fig. 1, of a two-stage gas turbine are mounted at the peripheries of rotor discs 15, 18 and are formed with abutting platforms 22 which provide part of the inner wall of the gas passage and the outer wall of tunnels 24 which extend axially between each adjacent pair of blades. The downstream ends of the tunnels are closed by plates 25, and the tunnels communicate with the inner ends of passages 26 formed in the blades. High-pressure rotor 15 is carried by a hollow shaft 16, and low-pressure rotor 18 is carried by a shaft 19 disposed axially within shaft 16. An air inlet pipe 28 passes through a stationary annular diaphragm 29 the inner edge of which is separated by a labyrinth seal 32 from shaft 16 and the outer edge of which carries an inwardly projecting ring 34. Four annular ribs 37 projecting axially from ring 34 co-operate to form a labyrinth seal with four annular ribs 39 projecting axially from an annular plate 31 attached to and spaced from the upstream face of disc 15. Ring 34 is formed in the annular space between the two inner ribs 37 with a series of nozzles 35 which are skewed in the direction of rotation of the rotor and communicate with the chamber 40 between ring 34 and plate 31. The latter is formed with an annular series of holes 41 which communicate with chamber 40. Cooling air from pipe 28 enters the manifold 30 constituted by the space between plates 29 and 31, then passes through the nozzles 35 into the chamber 40, and from the latter through the holes 41. Part of the air then flows outwardly into a manifold space 48 between plate 31 and the roots of blades 17, and from space 48 through the tunnels 24 to the passages 26 in the blades. The remainder of the air flows inwardly between a series of vanes 47 extending radially from plate 31, and passes through holes 50 in disc 15 into the space between shafts 16 and 19. Air is prevented from moving upstream by a labyrinth seal 51, and flows downstream to enter the space 52 between discs 15 and 18. The stationary guide vanes 12 between the blades 17 and 20 carry a ring 54, to the inner edge of which is secured outwardly extending rings 55 and 56, the ring assembly forming labyrinth seals 53 with the rotor discs. The annular space between rings 55 and 56 constitutes a manifold 57 which communicates via nozzles 66 in ring 56 with a chamber 65 formed between ring 56 and an annular plate 59 secured to and spaced from disc 18. Holes 67 in plate 59 connect chamber 65 to a manifold space 60 which communicates with the tunnels 24 between the blades 20 and hence with the cooling passages 26 in the latter. Space 52 communicates with the manifold 57 via holes 58 in ring 56. In a modification, Fig. 4, an air pipe 78 passes through a plate 75 which co-operates with a high-pressure rotor disc 73 to form a chamber 76. An annular plate 80, carried by plate 75, is spaced from the latter to form a chamber 81, and is also spaced, to form the chamber 84, from an annular plate 87 carried by and spaced from disc 73. Chamber 76 communicates via holes 79 in plate 80 with chamber 81, the latter communicating via nozzles 92 in plate 80 with chamber 84 which in turn communicates via holes 91 in plate 87 with a manifold space 90 communicating via tunnels 24 between the blades 74 of disc 73 with cooling air passages 26 in the blades.