GB833770A - Hollow turbine or compressor blades - Google Patents

Abstract

833,770. Turbine and compressor blades. DE HAVILLAND ENGINE CO. Ltd. Oct. 14, 1957 [Nov. 1, 1956], No. 33447/56. Class 110 (3). A hollow turbine or compressor blade is provided with a plurality of internal channels through which a fluid medium can be passed, for example for cooling the blades, a distributer block being provided in the root portion of the blade, the distributer having a plurality of passages communicating on the one hand with different internal channels in the aerofoil portion of the blade and on the other hand with a common chamber in a blade-supporting member to which the fluid medium is supplied, the channels being defined in part by at least one insert which is not part of the distributer block but is at least partly supported thereby, the distributer block also striving to retain the blade in the blade-supporting member. The turbine rotor blade shown is formed from a thin-walled metal tube to provide an aerofoil portion 10 and two tongue portions 13, 14 which are tranversely corrugated. An insert 15 comprising a hollow sheet metal body with longitudinally-corrugated sides 16 is inserted loosely into the hollow interior of the blade so as to define therewith a series of longitudinal cooling passages 17a, 17b, 17c, 17d. The lower end of the insert is formed to provide a stem 18 and a root portion 19. The tongue portions 13, 14 of the blade are entered axially into an open-ended groove 21 formed at the periphery of the rotor disc, the sides 22, 23 of the groove being shaped to correspond with the corrugations of the tongue portions. A distributer block is then inserted into the space between the two tongues 13, 14 to hold the blade in position. The distributer block is provided with an open-ended groove 29 in its upper surface, the groove being shaped to correspond with the shape of the root portion 18, 19 of the inert 15 so that as the distributer block is entered the root of the insert is engaged in the groove 29. A pin 30 is then entered into the root 19 whereby the insert is secured in position. The distributer block is formed with a series of passages 25, 26, 27, 28, the passages 25 communicating with the passages 17a in the aerofoil portion, passages 26 communicating with passages 17b, and passages 27 and 28 communicating with passages 17c, 17c, respectively. Cooling fluid is supplied to a groove 31 formed at the bottom of the blade-mounting groove 21, the fluid then flowing through the passages in the distributer block. The cooling fluid may discharge at the open tip of the blade and through apertures formed along the trailing edge. The insert may be formed in two halves with rectangular-shaped corrugations instead of triangular, as shown in Fig. 5. The distributer block may be of either rectangular, parallelogram or arcuate shape in cross-section normal to the axis of the blade.