Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/40—Casings; Connections of working fluid
  • F04D29/52—Casings; Connections of working fluid for axial pumps
  • F04D29/54—Fluid-guiding means, e.g. diffusers
  • F04D29/541—Specially adapted for elastic fluid pumps
  • F04D29/542—Bladed diffusers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D9/00—Stators
  • F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2240/00—Components
  • F05D2240/80—Platforms for stationary or moving blades
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/50—Intrinsic material properties or characteristics
  • F05D2300/502—Thermal properties
  • F05D2300/5021—Expansivity

Definitions

• the invention relates to an annular flow channel for an axial compressor, in which attached to an outer boundary wall of the flow channel blades in at least two ⁇ immediately successive rings are arranged in a radial manner.
• EP 2 194 234 A1 shows an axial compressor of a gas turbine whose flow channel merges into a compressor outlet diffuser.
• each compressor stage includes the last compressor stage - as seen in Strö ⁇ direction of flow of the compressed air - a ring of moving blades, the downstream followed by a ring of guide blades.
• EP 2194234 Al follows the guide vane of the last compressor stage, a further ring of Schaufelblät ⁇ tern, which are the same as the guide vanes fixed to the radially outer boundary wall of the flow channel.
• the white ⁇ tere array of airfoils is called vane.
• the Nachleitschaufein the fixed Nachleitrads have the task of exempting the airflow leaving the compressor as far as possible from swirl. By de-airflow elimination, this can build up the static pressure in the compressor outlet diffuser with comparatively low loss. Although the Nachleitrad contributes no contribution to the compression of the air sucked by the axial compressor, this structurally belongs to the axial compressor.
• Both the vanes of the last compressor stage and the Nachleitschaufein the Nachleitrades are formed according to the ⁇ be known axial compressor with freestanding blades, whose free-ending inner peaks a heat insulation ring each radial gap forming opposite.
• the heat insulation ring is part of a rotationally fixed shaft cover of the compressor rotor, which also forms the inner boundary of the compressor outlet diffuser at the same time.
• the concentric to the center axis shaft cover is thin-walled because of the rather minor mechanical stress and diffuser output side via not wei ⁇ ter shown struts ver ⁇ connected with the housing of the gas turbine.
• the housing of the axial compressor is relatively solid designed to withstand the pressure and temperature stresses during operation can. Furthermore, the housing is made relatively stiff.
• the load application to the housing during operation of the gas turbine leads only to small deformations.
• the shaft cover is formed with smaller wall thicknesses compared to the housing and typically has different material properties than the housing, the shaft cover heats up faster than the housing with the rows of guide vanes and the lead rows attached thereto. This has the consequence that when starting and when driving off the gas turbine, the shaft cover and the housing have a different thermal expansion rate, so that the An ⁇ drive and shutdown of the gas turbine, the size of the radial column changes, the radial gap when starting temporarily smaller and when driving off temporarily become larger or are.
• the tips of the blades do not abut the shaft cover during operation of the gas turbine and damage these, the radial gap is provided with such a dimensioned minimum ⁇ height that in each operating state of the gas turbine blade tips touch the shaft cover almost never.
• US 2,645,413 shows a fastening of vanes and an axial compressor outlet guide vanes, which are so well ⁇ housing side and the hub side secured to a support structure. This can lead to material stresses in the blades when during a transient operation, the respective support structures heat and stretch at different rates.
• the object of the invention is therefore to provide an annular flow channel for an axial compressor, which on the one hand bring about a particularly efficient and low-loss Entdrallung the last compressor stage leaving air flow and on the other hand has a comparatively simple construction in which the different rapidly expanding components in operation neither wear to be damaged.
• the annular Strö ⁇ flow duct surrounded by an outer boundary wall, on the immediately following one another in at least two Krän- zen airfoils are arranged radiating, wherein the blades of one of the two rings are connected with its radially inner end with a radially inner be ⁇ bordering inner ring inner ring, which has such a radial extent that the blades of the other of the two rings each with radial gap formation opposed to this.
• the invention has recognized that the radially inner Begren ⁇ Zung wall of the flow channel in the axial portion of the letz ⁇ th compressor stage and the guide vanes should not be part of the shaft cover, if possible, since the thermal tuning of the components is very difficult. Consequently, it is proposed to shorten the shaft cover, so that it forms only the inner boundary wall of the adjoining the axial ⁇ compressor compressor outlet diffuser . For this reason, the inner boundary wall of the axial ⁇ compressor in the region of the vane ring of the last compressor stage and the Nachleitrades of another
• one of ⁇ wreaths - preferably the vane ring of the last compressor stage - includes blades which are coupled on the head side via the inner ring and carry this and the other of the two rings - preferably the Nachleit- scoop - is with provided freestanding blades.
• the inner ring must then ne have such axial extent that this is also located in the axial portion of the free-ending blades.
• This construction has several advantages: on the one hand, it can also be used for existing axial compressors, without the housing of the axial compressor, in which the vanes of the last compressor stage and the guide vanes are mounted radially outward - foot side - must be changed.
• the invention has the advantage that it is comparatively easy to manufacture. This is especially true when the Nachleitrad is formed in principle of two mutually axially overlapping rows of blades, which can also be referred to as two overlapping Nachleitrate. Such components are relatively complicated to produce, if they are ⁇ over in a milling process to produce.
• the suspension of the inner ring takes place almost in the same axi ⁇ alen section as the foot-side attachment of the guide vanes.
• the inner ring is indirectly rigidly secured via the airfoil of the vanes to the outer boundary wall.
• the thermal behavior of the inner boundary wall of the flow channel (inner ring) and the free-standing, also attached to the outer boundary wall guide vane is much better ⁇ coordinated with each other than in the prior art.
• the free-standing Nachleitschaufel moves with the ther ⁇ mically comparatively fast-reacting outer boundary wall and the free-standing blade tip against ⁇ lying wall with the thermally rather sluggish wave swimming which previously required larger radial gaps.
• the improved tunability of the invention results in a coupling of the movement of the inner ring to the thermally induced movement of the outer boundary wall, whereby the gap of the radial gap is substantially independent of the thermal movements of the outer boundary wall.
• the Nachleitschaufein and the inner ring hold what flow losses significantly reduced and also causes a better Entdrallung the air flow as it enters the compressor outlet diffuser.
• wear between the inner ring and the free-standing airfoils can be reduced since the thermal behavior is far more predictable.
• Another advantage is that the isolation ring of the prior art can be omitted.
• the rim of Schaufelblät ⁇ tern - related to the flow direction of the flow passage - connected to the inner ring - upstream of the other ring is arranged.
• the inner ring bounding the flow channel inside can also be fastened to the guide track.
• the guide vanes of the last compressor stage as freestanding blades this radial gap forming against ⁇ lie.
• the invention closes - viewed in the axial direction - the shaft cover to the inner ring, between which two components preferably a sealing means is arranged to prevent leakage flow from the flow channel in a remote space therefrom.
• the outer boundary wall of the flow channel , an inner boundary wall of the flow channel and the inner ring each comprise at least two ring segments.
• the axial compressor is in total in a so-called. Dividing plane in which the machine axis is divided in half. Both the inner ⁇ ring and the outer boundary wall of the axial compressor must therefore not be formed from an element. On the one hand, this simplifies the manufacture of the components and, on the other hand, the assembly of the axial compressor.
• FIG. 2 shows a partial perspective sectional view of a Kran ⁇ zes with blades and an inner ring attached thereto with an axial extension.
• 1 shows a longitudinal section of the outlet portion 10 of an axial compressor 12 of a gas turbine 14.
• the axial displace ⁇ closer 12 includes an annular flow channel 16 which can be flowed through in the illustrated embodiment, from left to right.
• the flow channel 16 is on the output side in a diffuser 18 via.
• the axial compressor 12 includes a housing 20 formed as a guide vane, which is simultaneously the outer Be ⁇ grenzungswand 22 for the flow channel 16 and for the diffu- sor 18th Both the flow channel 16 and the
• Diffuser 18 are formed as annular channels, which extend konzen ⁇ trically around the machine axis 19.
• the axial compressor 12 further comprises a rotor 24, which For example, may be designed in disc design. A part of a rotor disk is provided with the reference number 26 in FIG. At the outer surface of blades 28 are hooked in a known manner with the aid of hammer-shaped feet 30.
• a rim 32 Downstream of the blades 28, there is provided a rim 32 which includes a plurality of vanes 34 radiantly attached to the boundary wall 22. Each of these guide vanes 34 has an airfoil 36, which is located in the flow channel 16. At the inner end 38 of the
• Blades 36, an inner ring 40 is arranged, which is supported by the vanes 34 and supported. Downstream of the vane ring 32, a further ring 42 is provided with a plurality of airfoils 44. The blade leaves 44 of the ring 42 are not assigned to a compressor stage of the axial compressor 12.
• the inner ring 40 comprises an axial extension 41 in a cylindrical shape, which faces the radially inner tips 48 of the airfoils 44 radial gap forming.
• the shaft cover has a projection 54 on its front side surface 52. This overlaps axially, but radially further inside the inner ring 40 partially. This makes it possible to arrange the annular sealing plate 56 in two mutually opposite grooves 58 and to seal the gap between the shaft cover 50 and the inner ring 40.
• 2 shows a perspective partially sectioned view of the vane ring 32 with a plurality of circumferentially successive vanes 34 whose head-side end are hooked to the inner ring 40.
• Each vane 34 has at its radially outer end a dovetail-shaped blade root 37 which is inserted in a groove 39 arranged in a retaining ring.
• a hammer-shaped blade head 49 is provided, which is hooked in a correspondingly shaped groove 43 of the inner ring 40.
• the inner ring 40 in this case comprises two parts 45, 47 which are connected to one another in the region of the display ⁇ felkopfes 49 for forming the groove 43rd
• the arrangement shown in FIG 2 comprising the ring 39, the blades 36 of the vane 34 and the inner ring 40 is also referred to as a guide plate, which is formed as well as the outer boundary wall 20 of the axial compressor 12 in the Re ⁇ gel of two ring segments, the ge ⁇ genüber manufacture ends can each be flange-connected to each other and screwed together.
• the invention provides an annular flow channel 16 for an axial compressor 12, in which blade blades 36, 44 of two blade rings 32, 42 are fastened to the outer boundary wall 22.

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Citations (6)

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• 2011
  • 2011-01-11 EP EP11150590A patent/EP2474744A1/de not_active Withdrawn
  • 2011-12-06 WO PCT/EP2011/071834 patent/WO2012095220A1/de active Application Filing

Patent Citations (6)

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