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
  • 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
• • 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
  • F01D5/12—Blades
  • F01D5/14—Form or construction
  • F01D5/18—Hollow blades, i.e. blades with cooling or heating channels or cavities; Heating, heat-insulating or cooling means on blades

Definitions

• the present invention relates to a turbine blade.
• a known type of turbine blade extends along a longitudinal axis and comprises an anchoring portion, a platform integrally coupled to the anchoring portion, a main elongated body and a cooling circuit in which a cooling fluid, generally air, flows.
• the air flow flowing in the cooling circuit removes heat by convection and lowers the temperature of the blade.
• the cooling circuit comprises a first cooling line for cooling a trailing edge of the main body of the blade, a second cooling line for cooling a central portion of the main body of the blade, and third cooling line for cooling the leading edge of the main body of the blade.
• the first cooling line comprises a first inlet opening arranged on a base face of the anchoring portion of the blade, a cooling duct which substantially extends over the whole length of the blade along the trailing edge of the main body of the blade, and a plurality of outlet slots arranged along the trailing edge of the blade.
• Blades of this type further comprise a metering plate which is arranged at the first inlet opening on the base face of the anchoring portion of the blade, so as to adjust the flow rate of air circulating in the first cooling line.
• the metering plates of known type are generally provided with three holes dimensioned so as to determine the passage of a given flow rate of cooling fluid, calculated during the steps of designing.
• the present invention relates to a turbine blade extending along a longitudinal axis comprising: an anchoring portion provided with a base face; a platform integrally coupled to the anchoring portion; a main elongated body, which extends from the platform on the opposite side with respect to the anchoring portion, and comprises a trailing edge; a cooling circuit, which comprises a first cooling line for cooling the trailing edge provided with a first inlet opening arranged on the base face of the anchoring portion of the blade; and a metering plate coupled to the base face at the first inlet opening; the blade being characterized in that the metering plate comprises a first portion and a second portion joinable to each other and shaped in such a way to define, together, an opening having a variable section.
• FIG. 1 is a perspective view of a turbine blade according to the present invention.
• FIG. 2 is a side plan view, with parts in section and parts removed for clarity, of the turbine blade in figure 1;
• - figure 3 is a bottom plan view of an element of the turbine blade in figure 1 in a first configuration
• - figure 4 is a bottom plan view of an element of the turbine blade in figure 1 in a second configuration.
• numeral 1 denotes a turbine blade (not shown in the accompanying drawings), which extends along an axis A and comprises an anchoring portion 4, a platform 5 integrally coupled to the anchoring portion 4, a main elongated body 6 which extends from the platform 5 on the opposite side with respect to the anchoring portion 4, a metering plate 7, a closing plate 8, and a cooling circuit 9 (shown in greater detail in figure 2) .
• the anchoring portion 4 may be inserted into a respective seat of a rotor disc (not shown in the accompanying drawings) in a direction parallel to the axis of the rotor disc, substantially orthogonally to axis A of blade 1.
• the anchoring portion 4 has a so-called "fir-tree" shape, substantially complementary with the shape of the respective seat of the rotor disc, but has a lower radial height than the radial height of the seat so that, once the seat is engaged, the anchoring portion 4 and the seat of the rotor disc create a channel (not shown for simplicity) for the passage of a cooling fluid, preferably air tapped from a compressor (not shown) of the system comprising the turbine.
• each blade 1 is provided with a base face 11, which is adapted in use to face the above-described channel for the passage of the cooling fluid.
• the main body 6 of blade 1 comprises a top section 13, commonly referred to as "tip”, opposite to the anchoring portion 4, a leading edge 14, a trailing edge 15, and a central portion 16.
• the cooling circuit 9 comprises a first cooling line 19 for cooling the trailing edge 15 of the main body 6 of blade 1, a second cooling line 20 for cooling the central portion 16 of the main body 6 of blade 1, and a third cooling line 21 for cooling the leading edge 14 of the main body 6 of blade 1.
• the first cooling line 19 comprises a first inlet opening 23 arranged on the base face 11 of the anchoring portion 4 of blade 1, a first cooling duct 24 which substantially extends parallel to axis A over the whole length of the blade 1 along the trailing edge 15 of the main body 6, and a plurality of outlet slots 25 arranged along the trailing edge 15 of blade 1.
• a metering plate 7 is arranged at the first inlet opening 23 to adjust the flow rate of air circulating in the first cooling line 19.
• the metering plate 7 is defined by a first portion 26a and by a second portion 26b, each of which is shaped so that the first portion 26a and the second portion 26b jointly define an opening 27 having a variable section.
• the coupling between the first portion 26a and the second portion 26b is of the geometric type and allows to couple the first portion 26a and the second portion 26b in a plurality of positions to define an opening 27 having a variable section.
• Figure 3 shows a metering plate 7 in a first position in which the section of the opening 27 is minimum and equal to about 28% of the section of the first inlet opening 23.
• Figure 4 shows a metering plate 7 in a second position in which the section of the opening 27 is maximum and equal to abut 38% of the section of the first inlet opening 23.
• the metering plate 7 is fixed to the base face 11 of the anchoring portion 4 of blade 1 in a given position corresponding to a given passage section of the opening 27.
• the passage section 27 is calculated once the flow rate of the cooling air flowing in the first cooling line 19, without calibration plate 7, has been experimentally measured.
• the metering plate 7 indeed corrects the error between the flow rate experimentally measured along the first cooling line 19 and the desired flow rate calculated during the steps of designing.
• the metering plate 7 is mainly used to correct machining errors which are generated during the step of forming the blade 1 by micro-casting and which determine a variation of the flow rate of the cooling fluid flowing in the first cooling line 19.
• the cooling fluid enters through the opening 27 of the metering plate 7 and through the first inlet opening 23 in the first cooling duct 24, and exits through the plurality of outlet slots 25 arranged along the trailing edge 15 of blade 1.
• a variation (not shown) provides for the metering plate 7 being provided with reference notches adapted to indicate the plurality of positions which may be taken by the first portion 26a and the second portion 26b to define the opening 27.
• the second cooling line 20 comprises a second inlet opening 30 arranged on the base face 11 of the anchoring portion 4 of blade 1, a second cooling duct 31 arranged as a serpentine and substantially defined by three segments 32a, 32b, 32c parallel to axis A, and a plurality of outlet holes 33 arranged along the central portion 16 of the main body 6 of blade 1 (some of the outlet holes 33 are seen in figure 1) .
• the cooling fluid enters through the second inlet opening 30 into the second cooling duct 31 and exits through outlet holes 33 arranged along the central portion 16 of the main body 6 of blade 1.
• the third cooling line 21 comprises a third inlet opening 35 arranged on the base face 11 of the anchoring portion 4 of blade 1, a third cooling duct 36 substantially parallel to axis A, and a plurality of film cooling holes 37 arranged along the leading edge 14 of the main body 6 of blade 1.
• the cooling fluid enters through the third inlet opening 35 into the third cooling duct 36 and exits through the film cooling holes 37 arranged along the leading edge 14 of the main body 6 of blade 1.
• the first inlet opening 23, the second inlet opening 30 and the third inlet opening 35 are eyelets defined by two rectilinear, parallel sidewalls and by two substantially circular sidewalls which join the two rectilinear sidewalls.
• the base face 11 of the anchoring portion 4 is further provided with a service hole 40, which is closed by a closing plate 8 and is not used for cooling the blade 1.
• the service hole 40 is indeed adapted to accommodate a supporting element (not shown) of the blade 1 during the process of forming the blade, preferably by micro-casting.
• the service hole 40, the first inlet opening 23, the second inlet opening 30 and the third inlet opening 35 are aligned along the base face 11 of the anchoring portion 4 of blade 1.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Engine Equipment That Uses Special Cycles (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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Citations (5)

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• 2009
  • 2009-06-04 IT ITMI2009A000977A patent/IT1394713B1/it active
• 2010
  • 2010-06-03 RU RU2011154326/06A patent/RU2528781C2/ru active
  • 2010-06-03 WO PCT/EP2010/057792 patent/WO2010139766A1/en active Application Filing
  • 2010-06-03 EP EP10724483.2A patent/EP2438273B1/en active Active

Patent Citations (5)

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