Patent GB-1230324-A (GB)
IPC: F01D5/18
Filed: 1969-03-05
Abstract: 1,230,324. Gas turbine blades - cooling. GENERAL ELECTRIC CO. March 5, 1969, No.11614/69. Heading F1 T . The invention relates to a means for cooling gas turbine bladed rotor structure in which the rotor disc rim is formed with axially-projecting portions, there being passageways extending through the axially-projecting portions which are in communication with the hollow interior of the blades mounted on the rim. The turbine assembly shown in Fig. 1 comprises a rotor disc 16 formed at its rim with a series of fir-tree grooves 17 in which rotor blades 19 are mounted, each blade comprising a core portion 58 defining a fir-tree root 18, a platform portion 28, and a radially-extending core 58, an aerofoil blade portion 59 being secured around the core 58. The core is formed with ribs 56, 57 which define cooling fluid ducts 53, 54 in the assembly. The platform portions 28 project axially beyond the rim of the rotor disc to define with adjacent stator structure annular gutters 39, 40 to which liquid coolant such as water is supplied from nozzles 29, 31 mounted in members 32, 33 forming part of the stator structure. Four passages 46, 47, 48, 49 are formed through each platform 28 through which coolant passes under centrifugal action from the annular gutters 39, 40 to the passages 53, 54 formed in each blade. The blade tips are inter-connected by a shroud ring 21 formed with circumferential ribs 62, the shroud defining with stator portions 23, 24 an annular chamber 27 into which coolant passing through the blade passages 53, 54 is discharged. Inclined vanes 61 are provided in the annular chamber 27 to re-direct some of the coolant back to the shroud ring. Coolant is supplied to the nozzle 29 through line 64 which passes through a hollow inlet guide vane 65, the guide vanes being cooled by flow of coolant from space 66 through the guide vanes to space 68. In Fig.4 the rim portion 83 of the rotor disc 85 projects laterally at each side, the surface of the rim being formed with annular grooves 88, 89, 91 and ridges 86, the blades 84 being of aerofoil shell form and mounted in appropriately shaped slots formed in the ridges. A cover plate 87 closes the outer sides of grooves 88, 89, 91. The lower surfaces of the rim define annular gutters to which liquid coolant is supplied, the coolant passing through passages 92, 93, 94, 96 to the annular grooves 88, 89, 91 and thence through openings 98, 99 in the blade portions into the cavities 97 defined by the blades 84. Openings (101), (102) Fig. 7 (not shown), may be provided inter-connecting the annular gutters 81, 82 directly with the blade cavities 97. In Fig. 8 (not shown) the blades are formed integrally with platform portions which have inwardly extending flanges (107) to define separate chambers (108) to which liquid coolant is supplied, the coolant passing through passages to the cavities (109) within the blades (106). In Fig. 9 (not shown) spacers (113) are mounted on the blades at an intermediate point, the spacers being formed with flanges (116) which define separate chambers to which liquid coolant is supplied, the coolant passing from the chambers through openings (118) into the cavities (117) within the hollow blades (111). In Fig. 11 (not shown) corrugated strips (123), (124) are disposed within the blade so as to confine the flow of coolant to adjacent the concave and convex walls thereof.