GB1188401A - Cooled Vane Structure for High Temperature Turbines - Google Patents

Abstract

1,188,401. Turbine and like blades. GENERAL ELECTRIC CO. May 5, 1967, No.21135/67. Heading FiT. A cooled turbine or like vane has a plurality of radially extending, axially spaced passageways formed in the body of the vane, one being provided adjacent the leading edge 37 and one adjacent the trailing edge 38, the remainder being intermediate the leading and trailing edges and inter-connected to form two serpentine passages 42, 43, 44 and 45, 46 each having a heat transfer fluid inlet 64, 65, a plurality of radially spaced openings 57, 58 interconnecting the first serpentine passage with the leading edge passageway 40 and the second serpentine passage with the trailing edge passageway 41, and a plurality of outlet passages 70, 72, interconnecting the leading edge passageway 40 with outlet openings in the leading edge region of the vane and the trailing edge passageway 41 with outlet openings in the trailing edge region of the vane. The invention is described with reference to a gas turbine rotor blade but is equally applicable to the vanes of gas turbine nozzle diaphragms and to vanes used in other high temperature turbomachines, such as high pressure compressors. The vane body 33 is aerofoil-shaped and the passageways 40 to 46 are radial holes extending inwardly from the radially outer end 50 of the vane body to the base portion. And end wall plate 52 is located in a recess 51 at the outer end 50 to close, except for bleed openings 53, the outer ends of the passageways 40 to 46. The openings 57 inter-connecting the radial passageways 40, 44 are sized to throttle flow of cooling fluid so as to enhance convection cooling at the leading edge region. Rows of radially spaced passages 70a, 70b inter-connect the leading edge passageway 40 and the convex and concave side wall surfaces 35, 36 respectively, two further rows of such passages 70c inter-connecting the passageway 40 and the leading edge 37. The axes of the passages 70a, 70b form an acute angle, preferably less than 30 degrees, with the surfaces 35, 36 so that the cooling fluid is discharged axially downstream and the axes of the passages 70c form an angle of approximately 30 degrees with the leading edge 37 so that the cooling fluid is discharged radially outward along the leading edge 37. The convection cooling at the leading edge region is supplemented by boundary layer cooling since the angular orientation of the passages 70 causes the discharged cooling fluid to be trapped in the boundary layer, thus insulating the vane body 33 from the hot combustion-products. The cooling fluid is relatively cool compressed air bled from an annular chamber which surrounds the combustion space of the gas turbine.