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EP-3957830-B1 - METHOD AND ASSEMBLY FOR MEASURING AT LEAST ONE GEOMETRICAL PARAMETER IN A BLADE ROW OR IN A VANE ROW OF A GAS TURBINE ASSEMBLY

EP3957830B1EP 3957830 B1EP3957830 B1EP 3957830B1EP-3957830-B1

Inventors

  • BIANCHI, ALESSANDRO
  • Tipa, Dario

Dates

Publication Date
20260506
Application Date
20200818

Claims (17)

  1. Method for measuring at least one geometrical parameter in a blade row or in a vane row of a gas turbine assembly (1); the method comprising: - coupling a first frame (40; 301) to one first blade or vane (25) of the blade or vane row; - coupling a second frame (41; 302) to one second blade or vane (25) of the blade or vane row adjacent to the first blade or vane (25); - coupling a measuring device (43; 305) to the first frame (40; 301) and to the second frame (41; 302); - measuring the geometrical parameter with the measuring device (43; 305).
  2. Method according to claim 1, wherein the step of measuring the geometrical parameter comprises measuring the stagger angle (α) of the first blade or vane (25).
  3. Method according to claim 2, wherein the measuring device (43; 305) comprises a goniometer; the goniometer comprising two longitudinal arms (62, 63), at least one of which is movable, and being configured to measure the angle defined between the two arms (62, 63).
  4. Method according to claim 3, wherein the first frame (40) comprises a first leading edge portion (45) arranged at the leading edge (32) of the first blade or vane (25) and a first trailing edge portion (46) arranged at the trailing edge (34) of the first blade or vane (25); the first leading edge portion (45) comprising a first leading edge support (49) and the first trailing edge portion (46) comprising a first trailing edge support (50); the first leading edge support (49) and the first trailing edge support (50) being arranged at a same first span height (S1, S2) of the first blade or vane (25).
  5. Method according to claim 4, wherein the second frame (41) comprises a second leading edge portion (55) arranged at the leading edge (32) of the second blade or vane (25); the second leading edge portion (55) comprising a second leading edge support (57); the second leading edge support (57) being arranged at a second span height (S3) of the second blade or vane (25) such that the second leading edge support (57) of the second blade or vane (25) and first leading edge support (49) of the first blade or vane (25) belong to a plane substantially orthogonal to the span-wise direction (S) of the first blade or vane (25).
  6. Method according to claim 5, wherein the step of coupling a measuring device (43) to the first frame (40) and to the second frame (41) comprises arranging the goniometer so as one arm (62) is coupled to the first leading edge support (49) and to the first trailing edge support (50) and the other arm (63) is coupled to the first leading edge support (49) and to the second leading edge support (57).
  7. Method according to claim 6, wherein the first arm (62) is arranged in contact with a trailing edge (32) and a leading edge (34) of the first blade or vane (25) facing a pressure side (37) of the first blade or vane (25), and the second arm (63) is arranged in contact with a leading edge (32) of the first blade or vane (25) and with a leading edge (32) of the second blade or vane (25).
  8. Method according to claim 1, wherein the step of measuring the geometrical parameter comprises measuring at least one throat distance (T1, T2, ..) between the first blade or vane (25) and the second blade or vane (25).
  9. Method according to claim 8, wherein the step of measuring the geometrical parameter comprises measuring a plurality of throat distances (T1, T2, ..) between the first blade or vane (25) and the second blade or vane (25) at different span heights of the first blade or vane (25).
  10. Method according to claim 8 or 9, wherein the throat distance (T1, T2, ..) is the minimum distance between the suction side (35) of the first blade or vane (25) and the pressure side (37) of the second blade or vane (25) at a defined span height.
  11. Method according to claim 9 or 10, wherein the measuring device (305) is an inner calliper provided with a first appendix (308) and a second appendix (309) configured to be arranged respectively in contact with the suction side (35) of the first blade or vane (25) and the pressure side (37) of the second blade or vane (25) facing each other.
  12. Method according to claim 11, wherein the first frame (301) comprises at least one first support (310) configured to block the first appendix (308) of the measuring device (305) on one first position of the suction side (35) of the first blade or vane (25) and the second frame (302) comprises at least one second support (312) configured to block the second appendix (309) of the measuring device (305) on one second position of the pressure side (37) of the second blade or vane (25); the first support (310) and the second support (312) being arranged at the same span heights (ST1, ST2, ST3..).
  13. Method according to claim 12, wherein the first support (310) and the second support (312) are holes configured to house the respective first appendix (308) and second appendix (309).
  14. Method according to anyone of the foregoing claims, wherein the blade row or the vane row is mounted in the gas turbine assembly (1).
  15. Assembly for measuring at least one geometrical parameter in a blade row of a gas turbine assembly 1; the assembly for measuring comprising: - a first frame (40; 301) configured to be coupled to one first blade or vane (25) of the blade or vane row; - a second frame (41; 302) configured to be coupled to one second blade or vane (25) of the blade or vane row adjacent to the first blade or vane (25); - a measuring device (43; 305) configured to measure the geometrical parameter and configured to be coupled to the first frame (40; 301) and the second frame (41; 302).
  16. Assembly according to claim 15, wherein the measuring device (43) is configured to measure the stagger angle (α) of the first blade or vane (25).
  17. Assembly according to claim 15, wherein the measuring device (305) is configured to measure at least one throat distance (T1, T2, T3..) between the first blade or vane (25) and the second blade or vane (25).

Description

TECHNICAL FIELD The invention relates to a method and an assembly for measuring at least one geometrical parameter in a blade row or in a vane row of a gas turbine assembly. The method and the assembly according to the invention is particularly useful for measuring geometrical parameters on blade rows or on vane rows already mounted in a gas turbine assembly for power plants. BACKGROUND As is known, a gas turbine assembly for power plants comprises a compressor, a combustor and a turbine. In particular, the compressor comprises an inlet supplied with air and a plurality of rotating blades compressing the passing air. The compressed air leaving the compressor flows into a plenum, i.e. a closed volume delimited by an outer casing, and from there into the combustor. Inside the combustor, the compressed air is mixed with at least one fuel and combusted. The resulting hot gas leaves the combustor and expands in the turbine. In the turbine, the hot gas expansion moves rotating blades connected to a rotor, performing work. Both the compressor and the turbine comprise a plurality of stator assemblies axially interposed between rotor assemblies. Each rotor assembly comprises a rotor disk rotating about a main axis and a plurality of blades supported by the rotor disk and arranged so as to form a rotating blade row. Each stator assembly comprises a plurality of stator vanes supported by a respective vane carrier and a stator ring arranged about the rotor to form a fixed vane row. During the operation of the gas turbine assembly, it is essential to maintain the geometry of the blade rows and of the vane row as stable as possible in order to guarantee the expected calculated performance. The performance of the gas turbine assembly, in fact, is very sensible to any variation from the design point. Therefore, during the maintenance service activities or during the assembling operations it is important to check the geometry of said blade rows and/or vane rows of the gas turbine assembly. However, for the maintenance service activities, the turbine assembly is turned off only for a limited period that have to be as small as possible in order to limit the economic losses. There are two kinds of inspections: minor inspections, during which the turbine assembly is stopped just for few days and the turbine assembly is not opened and major inspections, during which the turbine is opened for maintenance. During the minor inspections, the turbine assembly is normally inspected by a human operator, highly trained, which is normally called in the field as the "fact finder". Under these conditions, the fact finder inspects the blades and vanes. For example, to access the first stages of gas turbine, the fact finder passes through a manhole located on the combustor, while to access the other stages of gas turbine the fact finder passes through the diffuser at the outlet of the turbine. Especially in the first case, the space available for the movements of the fact finder is very restricted. Therefore, checking the geometrical parameter is not simple and rapid. A known method for checking geometrical parameters is disclosed, for example, in documents US 2016/245637 and US 4322887. SUMMARY Hence, it is an object of the present invention to provide a method that allows the fact finder to detect and measure as more parameters as possible regarding the geometry of accessible blades and/or vanes in a simple and rapid way. According to said object the present invention relates to a method for measuring at least one geometrical parameter in a blade row or in a vane row of a gas turbine assembly; the method comprising: coupling a first frame to one first blade or vane of the blade or vane row;coupling a second frame to one second blade or vane of the blade or vane row adjacent to the first blade or vane;coupling a measuring device to the first frame and to the second frame;measuring the geometrical parameter with the measuring device. A further object is to provide an assembly for measuring at least one geometrical parameter in a blade row or in a vane row of a gas turbine assembly as claimed in claim 15. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the accompanying drawings, which show a non-limiting embodiment thereof, wherein: figure 1 is a schematic sectional view, with parts removed for clarity, of a gas turbine assembly;figure 2 is a schematic top view, with parts removed for clarity, of the assembly for measuring at least one geometrical parameter in a blade row or in a vane row of a gas turbine assembly according to a first embodiment;figure 3 is a schematic top view, with parts removed for clarity, of the geometrical parameter measured by the assembly of figure 2;figure 4 is a schematic top view, with parts removed for clarity, of a first detail of the assembly of figure 2;figure 5 is a schematic perspective view, with parts removed for clarity, of a second detail of the assembly of figure 2