FR2485632A1 - IMPROVEMENT TO VENTILATION SYSTEMS OF TURBINE BLADES AND DISKS - Google Patents

Abstract

IMPROVEMENT OF THE VENTILATION SYSTEMS OF THE BLADES AND TURBINE DISCS, EACH VANE INCLUDING A FOOT ENGAGED IN ONE OF THE AXIAL ALVEOLES HOUSED AT THE PERIPHERY OF THE DISC. THE FOOT 3 OF THE DAWN SHOWS AT ITS LOWER FRONT PART A LEG OR SPOILER 7 ENSURING THE AXIAL LOCKING TOWARDS THE REAR BUTTING AGAINST THE UPPER FACE 1A OF THE TURBINE DISK 1, THE SAID LEG 7 WITH AN OPENING 8 FOR THE PASSAGE COOLING AIR IN AN ENCLOSURE 9 PROVIDED BETWEEN THE BOTTOM OF THE ALVEOLE AND THE LOWER FACE OF THE FOOT 3. THE INVENTION IS USED FOR VENTILATION OF THE BLADES AND TURBINE DISCS OF THE TURBORACTORS.

Description

Improvement to the ventilation systems of the blades and disks of

  The present invention relates to an improvement to the

  ventilation systems for blades and turbine disks.

  The air supply for cooling the foot of the turbine blades and the walls of the cells of the disk is generally provided from a capacity between the flange and the front face of the disk. The flange is bolted to the lower part of the disc and is supported, either on the front face of the disc teeth and on the blade root, or only on the front edge of the platforms

blades.

  It is also known to use plates mounted in circular grooves provided respectively in the blade platforms and in the disk, ports being

  provided in-plates for the-passage of air ..

  In these known devices, the seal between flange, blades and discs is not perfect and the games created by

many sources of leakage.

  It is therefore difficult to accurately assess the flow

  cooling air, resulting in a risk of over-

  heating of the disc teeth and feet of tines.

  According to the present invention, the foot of the blade provided at its front lower part has a lug or spoiler providing axial locking rearward, abutting against the upstream face of the turbine disc, said tab having an opening for the passage of the cooling air in a chamber formed between the bottom of the cell and the lower face of the foot, the axial locking to the front being provided by a flange fixed on the

  disc and against which comes a part of the dawn.

  The present invention thus allows a good seal between the flange, the blades and the disk by means of a very simple device ensuring both the cooling air supply of the foot of the. blades and their axial locking

rearward.

  Other features and advantages of the invention will be

  better understood by reading the description that follows

  of several embodiments and with reference to the accompanying drawings, in which Figure 1 is an axial sectional view of a blade of

  improved turbine according to the invention.

  FIG. 2 is a view of the front face of the blade

shown in Figure 1.

  FIG. 3 is a view in axial section of another mode

  embodiment of a turbine blade.

  FIG. 4 is a view of the front face of the blade

shown in Figure 3.

  FIGS. 1 and 2 show a rotor disc 1 in which axial cavities are formed at its periphery;

  2 each receiving a foot 3 of a turbine blade 4 which

  carries a platform 5 and a profiled portion 6 extending

  radially from each platform.

  The foot of the blade 3 has at its front lower part a lug or spoiler 7 abutted against the upstream face of the turbine disc, said lug having an opening 8

  for the passage of air-cooling in a

  girdle 9 formed between the bottom of the cell 2 and the face

lower 3a of the foot 3.

  The lower face of the foot 3 of the blade also has at the front a recess 12 to facilitate the passage of air. The enclosure 9 opens towards the downstream face of the disk by an orifice 10 so that the air escapes rearwardly deflected along the arrow F where it joins the

  vein between the mobile stage of the blades 4 and a reduced floor

11.

-

  The lug or spoiler 7 ensures the axial locking of the blade 4 to the rear while the locking is obtained by means of a flange 13 which comes to bear on the

5 'platform of the blades 4o -.

  The forward locking can also be obtained by means of the flange 13 which is borne simultaneously on the front face of the foot 3 of the blade and on the teeth 1b of the blade.

disk 1.

  In FIGS. 3 and 4, a variant embodiment is shown.

  sation in which the enclosure 9 between the bottom of the cell 2 and the underside of the foot 3 of the blade is closed to the downstream face of the disk by an elastic ring 14 engaged under a downstream spoiler 15 of the disk in which the

  ring 14 is maintained by elasticity on the one hand, but

everything by the centrifugal force.

  In the middle part of the foot 3, there is provided a conduit 16 connecting the enclosure 9 with the cavity 17 formed inside the profiled part 6 of the blade 4, said cavity 17 being in communication with the outside by ducts 18 and provided respectively in the leading edge and in the trailing bor.e. In this way the air cools the profiled part 6 of the dawn itself which is joined by well known means of

air circulation.

2 485632

  Naturally, various modifications may be made by those skilled in the art to the devices or processes which have just been described solely by way of nonlimiting examples.

  without departing from the scope of the invention.

- - -

Claims (7)

  1. Improvement to the ventilation systems of the blades and turbine discs, each blade comprising a foot (3) engaged in one of the axial recesses (2) formed at the periphery of the disc and a shaped part extending radially from each platform, characterized in   what the foot (3) of the dawn (4) has in its inferior part   a path or spoiler (7) ensuring the lock   axial lenght aft abutting against the upstream face (la) of the turbine disk, said tab having   an opening (8) for the passage of cooling air   in an enclosure (9) arranged between the bottom of   the cell (2) and the underside (3a) dou foot, the ver-   forward axial rusting being ensured by a flange (13) fixed on the disc and against which a part of dawn.   2. Improvement to vanes ventilation systems   and turbine disks according to claim 1, characterized   risé in that the enclosure (9) formed between the bottom of the cell (2) and the lower face (3a) of the root of the blade opens to the downstream face of the disk, so that the air s escapes rearwardly deflected into the air stream between a moving stage and a rectifier stage (11), 3. Improvement to vanes ventilation systems   and turbine disks according to claim 1,   characterized in that the enclosure (9) formed between the bottom of the cell (2) and the underside of the foot (3) of the blade is closed towards the downstream face of the disk and opens into a cavity (17) the profiled portion (6) of the blade (4) by a conduit (16) formed in the root of the blade, said cavity (17) of the profiled portion (6) of the blade comprising   orifices (18, 19) opening outwards.   4. Improvement to vane ventilation systems   and turbine disks according to claim 3,   characterized in that the enclosure (9) formed between the bottom of the cell and the inferior surface of the root of the blade is closed towards the downstream face of the disk by an elastic ring (14)   engaged under a tooth (15) of the dawn (4).   5. Improvement to vanes ventilation systems   and turbine disks according to claim 1 characterized   the lower face of the foot (3) of the blades (4) has at the front a recess (12) to facilitate the passage of the air.   6. Improvement to the ventilation systems and turbine disks according to the claim risé in that the forward locking is the flange (13) against which bears the of the platform (5) of the dawn (4).   7. Improvement to the ventilation systems and turbine disks according to the claim ized in that the forward locking is the flange (13) against which rests the (5) of the foot (3) of the blade (4). ) and the teeth (1b) (1). dawns 1, characteristics provided by the front edge of the blades 1, characteristics insured by the front of the disc