Classifications

• • 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
  • F01D3/00—Machines or engines with axial-thrust balancing effected by working-fluid
  • F01D3/02—Machines or engines with axial-thrust balancing effected by working-fluid characterised by having one fluid flow in one axial direction and another fluid flow in the opposite direction
• • 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
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/02—Blade-carrying members, e.g. rotors
  • F01D5/08—Heating, heat-insulating or cooling means
  • F01D5/081—Cooling fluid being directed on the side of the rotor disc or at the roots of the blades
  • F01D5/084—Cooling fluid being directed on the side of the rotor disc or at the roots of the blades the fluid circulating at the periphery of a multistage rotor, e.g. of drum type

Definitions

• the invention relates to a turbine shaft, which is directed along a main axis and has an inflow region for fluid, to which at least two recesses spaced apart from one another for receiving at least one respective turbine blade adjoin in the axial direction.
• the invention further relates to a method for cooling an inflow region of a turbine shaft arranged in a turbine, in particular a steam turbine.
• DE 32 09 506 AI deals with an axially loaded steam turbine, in particular in a double-flow version.
• an annular channel is formed between the shaft and an annular shaft shield.
• the shaft has a rotationally symmetrical depression in the area of the steam inflow. In this recess partially protrudes the Nng-shaped wave shield, which over the first
• Stator blade rows connected to the housing of the turbine and carried by this.
• the shaft shielding has passages for steam discharge, which are arranged centrally to the inflow area and between the first guide vanes and tangentially into the gap between the rotating ones
• DE 34 06 071 AI shows an annular shaft shield, which is arranged between the two rings of the first rows of guide vanes.
• the shaft shielding shields the outer circumference or the surface of the turbine shaft from the live steam. Upstream of the rings, the shaft shield has inlets through which a partial flow of live steam, throttled, reaches a gap between the shaft shield and the turbine shaft. The inlets are like this inclined that the live steam receives a flow component in the circumferential direction of the turbine shaft.
• Auxiliary guide vanes or auxiliary rotor blades can be provided on the inner circumference of the shaft shield and on the turbine shaft.
• the object of the invention is to provide a turbine shaft which can be cooled in a region which is subject to high thermal stress, in particular an inflow region for action fluid.
• a further object of the invention is to provide a method for cooling a turbine shaft arranged in a turbine, in particular an inlet area of the turbine shaft.
• the object directed to a turbine shaft is achieved by a turbine shaft which is directed along a main axis, an inflow region for action fluid, at least two recesses axially spaced apart from one another and recesses for receiving at least one respective turbine blade and one for the inflow region has a richly assigned cavity, which is connected to a feed line and a discharge line of a partial flow of the action fluid as a cooling fluid.
• the feed line leads preferably downstream of a first recess from the shaft surface into the cavity, and the discharge line leads from the cavity to the shaft surface downstream of a second recess. This second recess is further downstream than the first recess. This ensures that in the area of the second recess both a lower pressure than O 97/44568 PO7DE97 / 00970
• the cavity is preferably rotationally symmetrical to the shaft axis.
• the cooling of the shaft material significantly increases the load-bearing capacity of the shaft material and thus a more rational construction, e.g. the use of conventional, low-cost shaft materials also in the area of very high steam inlet temperatures.
• this can be a partial flow of already cooled action fluid, in particular steam, supplied to the turbine shaft in the inflow region.
• the cooling fluid used for cooling is heated in the cavity by heat transfer. If the cooling fluid corresponds to the action fluid for operating the turbine in which the turbine shaft is arranged, the cavity constitutes an intermediate superheater.
• the cooling fluid superheated therein can be returned to the turbine, in particular the steam turbine, at a suitable point (as the action fluid ) are supplied or by a
• the inflow region is preferably arranged along the main axis in the central region of the turbine shaft.
• the inflow area also serves a division of the inflowing action fluid that drives the turbine.
• the cavity is preferably deeply turned in the radial direction and lies in the axial direction between the respective first rows of moving blades.
• the inflow region lies in an end region of the turbine shaft, with the discharge leading through the housing according to the invention, for example back into the steam flow region, namely downstream of the first recess.
• This also ensures a pressure and / or temperature difference between the inlet of the inlet and the outlet of the outlet.
• the discharge line can also lead to a tap, so that the cooling fluid flowing out of the cavity can be drawn off directly from the steam turbine.
• the end region is preferably designed as a piston with an enlarged diameter.
• This piston has a seal that seals the steam flow area between the turbine shaft and the housing of the turbine.
• the cavity is preferably formed between the recess for the first row of blades and the piston.
• the lead preferably leads from the cavity into the piston and opens there in the area of the seal.
• the feed line and / or the discharge line preferably have a largely axial bore and a largely radial bore.
• the radial bore leads from the shaft surface m into the turbine shaft and merges into the axial bore, which extends from the cavity in the axial direction.
• the diameters of the supply and discharge lines are adapted to the corresponding steam conditions and the desired cooling.
• the size of the cavity is correspondingly adapted to the required cooling capacity.
• the cavity is preferably closed by a cover which is rotationally symmetrical, in particular, with respect to the shaft axis and which also serves as a flow deflection element can.
• the cover is preferably welded to the turbine shaft, thereby ensuring that cooling fluid and action fluid are guided separately from one another in the inflow area. Flow losses due to mixing are thus avoided.
• the cooling fluid in the cavity is not in direct contact with the hot action fluid which hits the outer surface of the cover, which is in particular vapor with a supercritical vapor state.
• the cover serves as a heat exchanger, so that heat is transferred from the turbine shaft to the cooling fluid both via the cover and via the walls of the cavity.
• the turbine shaft with cooling in the inflow region of hot action fluid is particularly suitable in a steam tower which is subjected to a supercritical steam state.
• the steam turbine can be a two-flow medium-pressure partial turbine or a single-flow steam turbine.
• the steam turbine can already be cooled by supplying fresh steam behind the first row of moving blades in such a way that safe operation of the turbine shaft in steam conditions with temperatures above 550 ° C. is ensured.
• the turbine shaft arranged on a method for cooling an inflow area in a turbine, in particular a steam turbine, is solved according to the invention by flowing action fluid, in particular steam with a supercritical vapor state, as cooling fluid into a cavity assigned to the inflow area downstream of a first row of blades is led out of the turbine shaft via a discharge line.
• action fluid in particular steam with a supercritical vapor state
• the partial flow of the action fluid serving as cooling fluid is taken from the inflow area at a first pressure level m and at a second pressure level m lower than the first pressure level, pressure level led out of the turbine shaft.
• This cooling can be constructed in a structurally simple manner by forming a corresponding cavity, for example by deep turning, with the associated discharge and supply line. Possible influences by the formation of the cavity with regard to the thermo-mechanical properties of the turbine shaft are more than compensated for by the cooling that is carried out.
• the turbine shaft with cooling of the inflow area is therefore also particularly suitable for steam with a supercritical steam state at temperatures of over 550 ° C.
• the cooling fluid is discharged from the turbine shaft, in particular in the case of a double-flow medium-pressure partial tower which is steamed, downstream of a second row of rotor blades, which is arranged further downstream than the first row of rotor blades. Since there is a pressure and / or temperature gradient between the inflow into the supply line and the outflow from the discharge line, the flow of the cooling fluid through the cavity is maintained without any compulsory measures.
• the cooling fluid is led out of the cavity via an end region of the turbine shaft through the discharge line m into the housing surrounding the turbine shaft.
• the cooling fluid can be introduced directly (as an action fluid) into a steam tap between the housing and the turbine shaft into a tap or downstream of the guide blade row lying further downstream than the first rotor blade row.
• the partial flow discharged from the steam flow driving the turbine shaft is thus made usable again, so that at most there is a slight influence on the efficiency of the turbine.
• the cooling fluid flowing into the cavity is heated - the cavity thus acts as an intermediate superheater - an increase in efficiency can even be achieved if necessary.
• a volume flow of steam of 1% to 4%, in particular 1.5 to 3%, of the total live steam volume flow which drives the turbine shaft is preferably fed to the cavity.
• the amount of steam supplied for cooling depends on individual parameters, such as steam conditions, materials used and the size of the steam turbine system.
• FIG. 1 shows a section of a longitudinal section through a double-flow medium pressure partial tower
• FIG. 2 shows a longitudinal section of a single-flow medium-pressure steam turbine.
• a turbine shaft 1 shows a section of a longitudinal section through a double-flow medium-pressure partial tower 15 of a steam turbine system.
• a turbine shaft 1 is arranged in a housing 19.
• the turbine shaft 1 extends along a main axis 2 and has in its central region 10 an inflow region 3 for action fluid 4a, in particular steam with a supercritical steam state.
• the housing 19 has a steam inlet 22 assigned to the inflow region 3, so that steam flows between the housing 19 and the turbine shaft 1.
• the steam is divided into two partial flows in the inflow region 3, as shown by flow arrows.
• the steam turbine 15 has a preferably deep-turned cavity 7 arranged in its central region 10. This cavity 7 is closed on its side facing the steam inlet 22 by a cover 11, which is welded to the turbine shaft 1.
• the lid 11 is curved in the direction of the Dampfemt ⁇ ttes 22, so that the division of the steam 4a into two partial steam streams is thereby supported.
• the turbine shaft 1 has, in the axial direction, recesses 5a and 5b which adjoin the Emström region 3 and are spaced apart from one another. These recesses 5a, 5b serve to accommodate turbine blades 6a, 6b, which each form a row of blades 16 and 17, respectively. For the sake of clarity, further recesses and rotor blades arranged therein are not shown.
• a corresponding row of guide blades 21 is provided on the housing 19. Downstream of the first recess 5a of the partial steam flow flowing to the right in FIG.
• a substantially radial bore 14 leading into the interior of the turbine shaft 1 is shown.
• This bore 14 m m an axial bore 13, which opens into the cavity 7.
• the two bores 14 and 13 form a feed line 8 which connects the shaft surface 12 to the cavity 7 in terms of flow technology.
• a further axial bore 13 leads from the cavity 7, into the turbine shaft 1 on the side of the cavity 7 opposite the feed line 8.
• This axial bore 13 merges into an essentially radial bore 14 which opens at the shaft surface 12 downstream of a second recess 5b.
• the latter two bores 13 and 14 represent a discharge line 9, through which steam 4b is returned from cavity 7 into the partial steam flow deflected to the left in FIG.
• the volume flow of steam 4b led through the inlet 8, the cavity 7 and the outlet 9 depends on the amount of heat to be dissipated, the output of the steam turbine 15 and other parameters. It can be between 1.5% and 3.0% of the total live steam volume flow. If necessary, in order to avoid asymmetrical loading of the turbine blades 6a, 6b arranged on the left and right sides of the inflow region, as a result of the steam throughput through the cavity 7, a suitable division of the entire live steam flow into two approximately equal partial flows flowing to the left or right is provided.
• the cooling of the turbine shaft 1 in the inflow region 3 improves its thermomechanical properties and ensures that the turbine shaft 1 is stable even under high-temperature loads of over 550 ° C.
• the steam turbine 15 has a housing 19 in which a turbine shaft 1 extending along the main axis 2 is shown. In an end region 18, the turbine shaft 1 is sealed with a shaft seal 24 with respect to the housing 19.
• the steam 4a for driving the turbine shaft 1 is fed to the steam turbine 15 through a steam inlet 22 and flows essentially along the main axis 2 through alternately arranged rotor blade rows 16, 17 and guide blade rows 21 to an outflow nozzle 23.
• the steam inlet 22 is connected to the steam inlet 22 an inflow region 3, which lies between the end region 18 and the first row of moving blades 16.
• the turbine shaft 1 has a cavity 7, which is closed with a cover 11 to the inflow area 3. Downstream of the first row of rotor blades 16, a feed line 8 leads through the turbine shaft 1 to the cavity 7. From this cavity 7, a discharge line 9 leads through the turbine shaft 1 to the shaft seal 24 and from there through the housing 19 to a tap 20 Between the Most blade row 16 and the tap 20 there is a temperature and / or pressure difference, so that steam 4b flows through the feed line 8 into the cavity 7 and from there via the discharge line 9 to the tap 20 without additional coercive measures. This steam 4b absorbs heat from the turbine shaft 1 via the walls, in particular the cover 11, and thus causes cooling of the turbine shaft 1. By absorbing the heat, the steam 4b in the cavity 7 is temporarily overheated and can thus continue to be used to increase the efficiency of the entire steam process, if necessary.
• the feed line 8 and the discharge line 9 can be constructed in a structurally simple manner as bores.
• the invention is characterized by a turbine shaft which has a cavity in a thermally highly stressed inflow region, to which fluid for cooling can be supplied.
• the cooling fluid supplied to the cavity is preferably branched off from the total flow of steam or gas driving the turbine shaft.
• a fluidic connection of the cavity to areas in which different pressure and / or temperature states of the steam or gas prevail ensures a constant flow through the cavity, which is brought about without additional coercive measures.
• a heat transfer from the turbine shaft to the cooling fluid, in particular water vapor, takes place through the walls of the cavity, as a result of which the turbine shaft is reliably cooled and the cooling fluid is reheated.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Heat Treatment Of Articles (AREA)

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• 1996
  • 1996-05-23 DE DE19620828A patent/DE19620828C1/de not_active Expired - Lifetime
• 1997
  • 1997-05-14 AT AT97924884T patent/ATE247767T1/de not_active IP Right Cessation
  • 1997-05-14 WO PCT/DE1997/000970 patent/WO1997044568A1/fr active IP Right Grant
  • 1997-05-14 CN CN97194241A patent/CN1079491C/zh not_active Expired - Lifetime
  • 1997-05-14 ES ES97924884T patent/ES2206713T3/es not_active Expired - Lifetime
  • 1997-05-14 CZ CZ982966A patent/CZ296698A3/cs unknown
  • 1997-05-14 DE DE59710620T patent/DE59710620D1/de not_active Expired - Lifetime
  • 1997-05-14 EP EP97924884A patent/EP0900322B1/fr not_active Expired - Lifetime
  • 1997-05-14 PL PL97329689A patent/PL329689A1/xx unknown
  • 1997-05-14 JP JP54136497A patent/JP3943135B2/ja not_active Expired - Fee Related
• 1998
  • 1998-11-23 US US09/198,218 patent/US6082962A/en not_active Expired - Lifetime

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