GB737245A - Improvements relating to the compressor intakes of gas turbine engines - Google Patents

Abstract

737,245. Gas turbine plant; turbine blades. GENERAL MOTORS CORPORATION. Oct. 17, 1953, No. 28692/53. Class 110 (3). A gas turbine compressor intake member comprising inner and outer shells connected by radial struts having radial passages formed adjacent their leading edges, has the inner ends of the passages connected by an annular manifold and axial hot gas supply ducting connected to the outer ends of a minority only of said radial passages, so that the hot gas flows radially inward through the minority of radial passages and then by way of the manifold flows radially outward through the remaining radial passages. The compressor air intake member 10 shown comprises an inner wall 12 and outer wall 11 connected by a plurality of struts 13, 14. The discharge end of the intake member is provided with an annular row of vanes 18 which impart swirl to the air entering the compressor. The inner wall 12 supports a roller bearing 27 in which a stub shaft 20, attached to the compressor rotor disc 19, rotates, and a ballbearing 29 in which a shaft 32 which drives engine auxiliaries or supplies useful power, rotates. The shaft 32 has splines which engage internal splines in the stub shaft 20. During operation, ice is likely to form on the leading edges of the struts 13, 14 and the inlet guide vanes 18, and to prevent this, hot air, which may be drawn from an intermediate or late stage of the compressor, is led through two passages 38, in the compressor casing 24 to the passages 39 in the air intake member 10. This air then passes through the passages 40 in the leading edge of the struts 13 to an annular manifold 42 formed by a groove in the outer surface of a bearing support ring 28. From the manifold 42 the air is distributed through passages in the leading edges of the struts 14. Each strut 14 has a radial bore 43 extending from the manifold to the exterior surface of the intake member 10 which is closed at its outlet end by a plug 44. Each plug 44 carries a tube 46 which extends to the inner end of the bore 43 and which has an annular collar 47 which is a sliding fit in the bore approximately at the middle of its length. A broken collar is, or projections 48 are, fixed to the tube 46 at its inner end. A part of the heating fluid from the manifold 42 flows through the tube 46 to ports 49 from which it flows inwardly and is discharged through small openings 51 in the side walls of the strut 14 into the air stream flowing into the compressor. The remainder of the heating fluid passes through the openings 52 in the collar 48 and flows through the annular passage outside the tube 46 to openings 53 in the side walls of the strut 14. The collar 47 separates the two flows. The size of the openings 49, 51, 52 and 53 determines the rate of flow and the balance of flow between the inner and outer ends of the struts. The inlet guide vanes 18 are attached to inner and outer shroud rings 61, 60. The outer shroud ring 60 is retained in position by the forward face of the compressor casing 24 and forms with the outer wall 11 of the air intake member 10 a manifold 72. The inner shroud ring 61 is spigoted on to the inner wall 12 of the air intake and is retained in position by a ring 63 bolted to the inner wall. Rivets 67 fixed in the flange 62 of the inner shroud ring 61 fit in radial slots in the ring 63 and prevent rotation of the vane assembly. A hot air manifold 71 is formed between the inner wall 12 and the shroud ring 61. The manifolds 71, 72 are sealed by 0-rings 73, 68, 69. A short passage 74 connects the passage 39 with the manifold 72. A radial passage 76 in the strut 13 leads hot air from the passage 39 to a passage 77 leading to the manifold 71. The guide vanes 18 are of aerofoil shape, Fig. 7, and comprise a body 80 to which a sheet metal facing 81 is brazed at 82. The facing 81 forms a radial air passage 83 at the leading edge of the vane and is spaced from the concave face of the vane by ribs 85 so that hot air from the passage 83 can be exhausted from the blade at the trailing edge 86. The vanes are welded to the outer shroud ring so that the passages 83, which are aligned with holes 84 in the shroud ring 60, project through the inner shroud ring. Hot air is thus supplied to the passages 83 from both of the manifolds 71, 72.