GB880069A - Improvements in or relating to turbine or like blades and rotors incorporating such blades - Google Patents

Abstract

880,069. Turbine and compressor blades. ROLLS-ROYCE Ltd. May 27, 1959 [Aug. 28, 1958], No. 27729/58. Class 110 (3). A turbine or compressor blade is formed with internal fluid-flow passages to carry cooling or heating fluid and there is at least one passage having two passes extending lengthwise through the blade and into the root, one pass leading from an inlet in a surface of the root other than a circumferentially facing surface and the second pass leading to an outlet in a circumferentially-facing surface of the root, the passes being joined in series from the inlet to the outlet, there being provided also at least one single pass passage leading from an inlet in a circumferentially-facing surface of the root to an outlet in the blade tip. In the bladed turbine rotor shown, the blade comprises an aerofoil portion 13, a root and a tip shroud 14, the root itself comprising an attachment portion 15, a platform 16 and a circumferentiallynarrow stem portion 17 therebetween. The blade is mounted by entering its attachment portion 15 in a correspondingly-shaped recess formed in the rim 11 of the rotor disc 10, a shallow recess 20 in the rotor disc co-operating with a recess 21 at the bottom of the attachment portion 15 to form a chamber to which fluid such as high-pressure air is supplied from space 18 through bores 19. Three bores 22, 23, 24 communicate with the chamber 20, 21 and extend through the attachment portion 15 and stem 17. The bore 22 leads to a pair of two-pass passages formed side-by-side in the blade, each passage comprising a pass 25 through which fluid flows radially-outwardly and a pass 26 through which fluid flows radiallyinwardly. The passes 25, 26 of each passage are connected by a transfer passage 27 formed in the tip shroud 14 and closed by a plate 28 welded to the tip shroud. The passes 26 communicate with a fluid outlet orifice 30 formed in one of the circumferentially-facing surfaces of the stem 17. Two single-pass passages 33 disposed side-by-side also extend through the blade from an inlet orifice 34 in the other circumferentially-facing surface of the blade stem 17 to outlets in the tip shroud. The bores 23, 24 communicate with further single-pass passages 31, 32 respectively extending through the leading and trailing edge portions of the blade, the passages having outlets through the tip shroud 14. The spaces between adjacent blade stems 17 are closed at their ends by sealing plates 36 whereby fluid discharging through an outlet 30 in one blade after flowing through the passages 25, 26 then enters the inlet 34 of the adjacent blade to flow through the passages 33.