FR2484015A1 - ROTOR DARK COMPRISING A HAT OF STACKED PLATES CONSTITUTING THE HEAD OF THE DAWN - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS A ROTOR VANE INCLUDING A CAP OF STACKED PLATES CONSTITUTING-1A AS A DAWN HEAD. THE HAT OF THE DAWN'S HEAD IS MADE FROM A PLURALITY OF PLATES ARRANGED IN THE DIRECTION OF THE ROPE. THE OUTSTANDING PLATE 30 INCLUDES A LIP 26 SURROUNDING THE PERIPHERY OF THIS PLATE. THE INTERNAL PLATES 32 INCLUDE SIDE PASSAGES SHAPED BETWEEN THE ADJACENT PLATES AND MADE ACCORDING TO A PPE MODEL TO ESTABLISH A ZONE IN ONE PLAN, SENSITIVELY UNIFORM COOLING BY CONVECTION IN DAWN.

Description

The present invention relates to a rotor blade comprising a cap of

  platesemafiis constituting the head of the dawn and refers to the blades of rotary machines with axial flow. The principles have been developed in the industry

  gas turbine engines for use in the

  engines, but are applicable to other

  rotary machines operating at high temperature.

  In gas turbine engines, very high temperature working gases are produced in a combustion chamber and pass through the downstream turbine section. At the upstream end of the turbine part, the working gases have characteristic temperatures of the order of 13700C or more. The temperature of the working gases in many cases exceeds the resistance capabilities of the materials from which the turbine components are made and such elements are cooled with lower temperature air to prevent

  deterioration or destruction of these elements.

  The blades of the rotor at the end upstream of the

  part of the turbine are usually

  say. The vanes extend outwardly over the engine rotor across the working gas path and are opposed at their outer ends to a bandage surrounding them, applied to the motor stator. The game between the blade heads and the bandages is necessarily rendered

  small to discourage leakage of working gases from

  above the heads and avoid a decrease in aerodynamic efficiency that results. With such small games to

  heads of the blades, in particular during

  engine operation, the occasional blades

  Then rub against the bandage around it. A possibility of destructive interaction exists during such friction both by the fact. a mechanical deformation of the blade or the bandage and the fact of the formation of thermal tensionsexcessives during the moment of the friction. The blade heads are usually cooled as shown in US Patent Nos. 3,899,267,

3,994,622 and 4,010,531.

  The bandages surrounding the vanes are usually formed of abrasion-abradable or deformed materials designed to accommodate frictional contact with the vanes without destructive interaction. US Patent Nos. 3,042,365, 3,854,842, 3,817,719, 3,879,831 and

  3,918,925 show examples of such structures.

  Despite the structures and subject systems developed in the past, scientists and engineers in the industry continue to look for improved blades and bandages. Rotor blades having a high resistance to destructive deformation and which are cooled

  effectively in the area of their heads are particular goals.

sought after.

  According to the present invention, a head is made

  rotor blade having a substantial capacity for trans-

  convection heat near the surfaces susceptible to friction at the head of the blade, this blade head being constituted by a plurality of plates arranged in the direction of the rope and stacked in the longitudinal direction, passages cooling being

  arranged between them according to a distribution in the plane.

  A main feature of the present invention is the structure consisting of plates forming the hat of the blade head. The plates are arranged in the direction of the rope through the head of the blade to cover the cavity of the cooling air therein. Cooling air passages between the plates establish a cooling unit to move the thermal energy away from the friction surfaces

  at the head of dawn. The outermost plate in

  Some embodiments are provided to have the configuration of a blade head pattern including a raised lip extending around the periphery of the blade head to minimize the amount of surface area in contact with the blade head. rubbing with the bandage

surrounding dawn.

  A main advantage of the present invention is the possibility of increasing the effective cooling capacity very close to the energy generating source.

24814O5

  -3 thermal. An uninterrupted flow of cooling air is guaranteed by lateral unloading of the air rather than unloading of air through the head. Cooling capacity is not reduced during periods of

  rubbing contact with the surrounding bandage.

  In order that the invention may be better understood, reference is made to the following figures: FIG. 1 is a perspective view of a gas turbine engine rotor blade representing the

  hat of the blade head according to the invention.

  Fig. 2 is an enlarged view of the region of the blade head of Fig. 1 showing the plates arranged in the rope direction, which comprises a blade head cap, parts being exploded to reveal the configuration. convection cooling currents according to a distribution in a plane with a

orientation "on the cob".

  The rotor blade 10 of FIG. 1 is an example

  rotor blade of the type to which the principles according to the invention

  apply. The blade has three main sections: a root portion 12, a platform portion 14, and an aerodynamic portion 16. The outer end 18 of the aerodynamic portion is referred to as the portion of the blade head. The dawn comprises one or more cavities where the cavity 20 of the

  leading edge and the cavity 22 of the rear edge, which extends

  tooth from the root part of dawn through the

  aerodynamics for the distribution of cooling air

  dissement. The cavities are closed at the outer end of the aerodynamic portion by a blade head cap 24 comprising a lip 26 facing outward which

  is elevated from the support structure.

  In its operating environment, the root portion 12 of the blade may be attached to the rotor disc (not shown) of a gas turbine engine, the aerodynamic portion 16 extending outwardly through

  pathway for working gases in the engine.

  The platform part 14 forms part of the limit

  dull of the course. The outer boundary of the course is formed in part by a bandage surrounding the blades -4- (also not shown) which is opposite to the raised lip of the blade head and is arranged very close to

it. -

  In the embodiment of the present invention,

  In Figure 2, the aerodynamic part 16 is manufactured

  from a plurality of plates 28 disposed longitudinally

  which are welded by a suitable technique such as diffusion welding. Similarly, the cap 24 of the head is made from a plurality of plates arranged in the direction of the rope, comprising an outermost plate 30 and one or more plates

  internal 32 which are stacked in the longitudinal direction.

  The blade head cap closes the outer ends of the leading edge cavity 20 and the rear edge cavity 22. The inner plates 32 are manufactured in one

  metal material having a comparable or identical composition

  to the material from which the aerodynamic part

  that dawn is manufactured. The outermost plate 30 is made of the same material and has a lip

  Raised around the periphery of the

  mite of dawn. The raised lip is a minimum surface area on the blade head exposed to contact by

  friction with the bandages surrounding the blades. The tendencies

  Excessive heat losses are therefore avoided when the blade head is worn to fit the bandage geometry. The plates are welded for example to each other and to the plates arranged longitudinally of the aerodynamic part, also by a suitable technique

such as diffusion welding.

  The side passages 34 for the cooling air flow are formed at the interface 36 between a pair of adjacent plates. One portion of the passages 34 of the illustrated embodiment extends from the interior of the blade to one of the cooling air chambers laterally to the surface 38 of the pressure side of the aerodynamic portion. The remaining portion of the passages 34 extend from the dawn interior and laterally to the

  the surface 40 of aspraticn side of the aerodynamic part.

  Laterally extending passages may be formed

24QO 'O5

  -5- in one side of a single plate and can be formed

  in opposite sides of two adjacent plates and

  arranged to fit. Profiling and decapping

  are two of the techniques suitable for the realization

passages.

  The blade head caps made according to the principles of the present invention are very advantageous in that they are able to establish substantial convective cooling very close to the thermal energy generating locations. A cooling unit to drive thermal energy away from places is

  generators of energy- / established by the multiple

  and in particular by the passages 34 extending laterally

  Figure 2. Side passages establish an area in a plane, convection cooling

substantially uniform.

  The plate structure is well suited for the manufacture of side passages, particularly at interfaces between plates where complicated geometry and contour passages may be formed before the plates are welded. The arrangement of the cooling unit very close to the friction surfaces as in the present invention allows the dissipation of heat without destroying the

matter of the dawn head.

  A high density of passages is necessary for

  guarantee adequate cooling by convection.

  Although fewer numbers of passes have been used in known plate structures, such structures typically rely on at least parts of the skin to cool the outer surfaces of the blade against working at high temperature. The structure described

  here admits that when friction occurs, the cooling

  film damage on the blade head is interrupted precisely when a maximum heat removal capacity is required. Such an interruption of

  cooling capacity is avoided.

  The embodiment of dawn head hat se-

  The invention is shown in combination with a blade made by radial plate techniques. The principles are fully compatible with material systems and manufacturing techniques used with

  radial plate structures and, as such, probably

  are most useful in this area.

  born. The known principles in the field of flat blades

  which are those described in the US Patents

3,872,563 and 4,203,706.

  Of course various modifications can be made by those skilled in the art to the rotor blade which has just been described by way of non-limiting example

  without departing from the scope of the invention.

240L91 5

-7-

Claims (4)

claims:   A rotor blade of the type comprising at least one longitudinal cavity extending from the root portion to the head of the blade for distributing cooling air, characterized in that it comprises a cap (24) disposed on the end of the blade head of the cavity and is formed by a plurality of longitudinally stacked plates (30, 32) arranged in the direction of the rope and at least two such plates   (32) include a first series of cooling passages   trench (34) extending laterally, form. between them which are oriented so as to be able to discharge the cooling air from the longitudinal cavity to the pressure side (38) of the blade.   2. rotor blade according to claim 1, characterized in that these plates (32) comprise a second series of cooling passages (34) extending laterally, formed between them which are oriented so as to be able to discharge the air cooling from the cavity   longitudinal towards the aspiaticn (40) of the dawn.   Rotor blade according to Claim 2, characterized   in that this first and second series of pass-   ges (34) extending laterally are arranged in a   model in order to obtain an area in a cooling   convecton deformation substantially uniform in the dawn Operating.   4. rotor blade according to any one of the claims   1 to 3, characterized in that the outermost (30) of these plates (30, 32) comprises a thin lip (26).   extending around the periphery of the end of the be.