U.S. patent application number 14/615487 was filed with the patent office on 2018-07-26 for in-situ measurement of blade tip-to-shroud gap in turbine engine.
The applicant listed for this patent is Siemens Energy, Inc.. Invention is credited to Alejandro Bancalari, Joshua DeAscanis, Clifford Hatcher, Jr., David Letter.
Application Number | 20180209296 14/615487 |
Document ID | / |
Family ID | 62905996 |
Filed Date | 2018-07-26 |
United States Patent
Application |
20180209296 |
Kind Code |
A1 |
DeAscanis; Joshua ; et
al. |
July 26, 2018 |
IN-SITU MEASUREMENT OF BLADE TIP-TO-SHROUD GAP IN TURBINE
ENGINE
Abstract
A robotically articulated inspection scope (56, 69) inserted
into a pilot fuel nozzle port (58) of a turbine engine (20) for
in-situ measurement of gaps (59) between tips of turbine blades
(40A) and the surrounding shroud (44). A non-contact gap measuring
device (52) on a distal end (79) of the scope may be navigated
through a combustor (28) and transition duct (34) into a position
proximate a blade tip gap. The scope may be controlled via computer
(68) via a robotic drive (66) affixed to the pilot fuel nozzle
port. Multiple scopes may be used to measure gaps (59A-D) at
multiple azimuths of the turbine simultaneously. The turbine disk
(37) may be rotated on its operating turning gear to sequentially
measure each blade at each azimuth. The computer may memorize an
interactively navigated path for subsequent automated
positioning.
Inventors: |
DeAscanis; Joshua; (Oviedo,
FL) ; Letter; David; (Deland, FL) ; Bancalari;
Alejandro; (Casselberry, FL) ; Hatcher, Jr.;
Clifford; (Orlando, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Energy, Inc. |
Orlando |
FL |
US |
|
|
Family ID: |
62905996 |
Appl. No.: |
14/615487 |
Filed: |
February 6, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 7/18 20130101; F01D
21/00 20130101; F01D 21/003 20130101; F01D 11/08 20130101; G01M
15/14 20130101 |
International
Class: |
F01D 21/00 20060101
F01D021/00; H04N 7/18 20060101 H04N007/18; H04N 5/33 20060101
H04N005/33; G01M 15/14 20060101 G01M015/14 |
Claims
1-15. (canceled)
16. A method of inspecting a gap between a tip of a turbine blade
and a surrounding gas path shroud in a gas turbine engine,
comprising the steps of: a) providing a robotically articulated
inspection scope comprising a non-contact gap measuring device on a
distal end thereof; b) inserting the inspection scope into a pilot
fuel port of a combustor of the gas turbine engine without
separating halves of a casing of the engine; c) robotically
navigating the non-contact gap measuring device through the
combustor and through a transition duct of the gas turbine engine
to a position proximate a gap between a tip of a blade on a turbine
disk and a surrounding gas path shroud in the gas turbine engine;
d) measuring the gap with the non-contact measuring device, and
storing a width dimension of the gap in a computer; e) rotating the
turbine disk to position a next blade of the turbine disk proximate
the non-contact measuring device; f) repeating from steps d) and e)
until gaps associated with a plurality of blades on the turbine
disk have been measured; sensing a temperature of the gas path
shroud and the blade tip, respectively, during the measuring step;
wherein the non-contact gap measurement device comprises an
infrared camera or thermocouple that senses the respective
temperatures of the gas path shroud and the blade tip and wherein
the first gap width is determined as a function of the respective
temperatures.
17. (canceled)
18. The method of claim 16, further comprising repeating steps d)
and e) at a plurality of temperatures as the engine is cooled from
an operating temperature to ambient following shutdown of the
engine.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to the field of gas turbine
engine inspections, and more particularly to the measurement of
clearance between gas turbine blade tips and the surrounding gas
path shroud, and specifically to an apparatus and method for making
such measurements in-situ without disassembly of the engine
casing.
BACKGROUND OF THE INVENTION
[0002] Gas turbine engines commonly have one or more combustors
surrounding the engine shaft between a forward compressor and an
aft turbine. The turbine has one or more circular arrays of
rotating blades alternating axially with stationary vanes.
Combustion gas from the combustors is ducted to the first row of
turbine blades. Critical clearance exists between the blade tips
and the surrounding combustion gas path shroud. An increase in this
clearance reduces engine efficiency and indicates wear. Current
methods for measuring blade tip clearance require removal of at
least the upper half of the turbine outer casing, and the use of
feeler gauges. However, removing the casing changes stresses in the
engine such that the measurement may not accurately represent the
clearances in the assembled turbine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The invention is explained in the following description in
view of the drawings that show:
[0004] FIG. 1 is a partial sectional side view of an upper half of
a gas turbine engine known in the art.
[0005] FIG. 2 is a sectional side view of an inspection scope
inserted through a combustor and transition duct showing aspects of
an embodiment of the invention.
[0006] FIG. 3 is a sectional side view of a distal arm of the
inspection scope with a non-contact gap identification and
measuring device proximate a first row of turbine blades.
[0007] FIG. 4 is a sectional side view of a distal arm of the
inspection scope illustrating another aspect of the invention.
[0008] FIG. 5 is a transverse sectional view of a turbine disk
showing exemplary multiple blade tip gap measuring positions.
DETAILED DESCRIPTION OF THE INVENTION
[0009] FIG. 1 is a partial side sectional view of an upper portion
of a gas turbine engine 20 with a compressor section 22, a
combustion section 24, and a turbine section 26 as known in the
art. One combustor 28 of a circular array of combustors is shown.
Each combustor has an upstream end 30 and a downstream end 32. A
transition duct 34 transfers the combustion gas 36 from the
combustor to the first row of airfoils of the turbine section 26.
The turbine section includes stationary vanes 38 and rotating
blades 40. The first row of airfoils may be a circular array of
stationary vanes 38A. This is followed by a first row of rotating
blades 40A mounted on a disk 37 attached to a turbine shaft 41 that
drives the compressor blades 42. Pilot fuel 42 enters each
combustor via a central pilot fuel nozzle 43. Compressed air 45
enters a plenum 46 around the combustors. It then enters the
upstream end 30 of the combustor, and is mixed with fuel therein
for combustion. The compressed air 45 also surrounds the combustor
28 and transition duct 34 to cool them. It has a higher pressure
than the combustion gas 36 in the combustor and in the transition
duct. Maintenance access ports 47 are provided at various locations
on the engine, including on the outer casing 39 of the combustion
section as shown.
[0010] FIG. 2 shows a combustor assembly 28 including a combustion
chamber 50 affixed to a combustor cap 51 that is mounted in a
combustor support housing 48. The pilot fuel nozzle 43 of FIG. 1
has been removed from the pilot fuel nozzle port 58, and an
elongated inspection scope 56, 69 is inserted into the port,
extending through the combustor cap 51, combustion chamber 50, and
transition duct 34. A mounting tube 60 for the inspection scope may
be affixed to the pilot fuel nozzle port 58 via a collar 62 or
other means. The collar may be rotationally indexed to the port by
an indexing mark or key in order to establish the rotational
orientation of the inspection scope relative to the combustor for
repeatable automatic navigation. A computer 68 may control the
scope robotically via a motorized drive 66 to extend through the
combustor and navigate to the position shown. This can be done for
example as taught in US patent application publication
2013/0335530A1, which is incorporated herein by reference or by
other robotic mechanisms. Herein "robotically" means controllably
operated by a computer along an automated predetermined navigation
path and/or operated interactively under human direction via the
computer. The scope may have a distal arm 69 robotically
articulated at a pivot joint 64 connected to a distal end of an
upper arm 56 of the inspection scope. A non-contact gap
identification and measuring device 52 is mounted on the distal end
of the distal arm 69 with a video camera 53 for visual navigation
via the computer 68 to measure the gap between the tip of a blade
40A and the surrounding gas path shroud 44.
[0011] The measuring device may be laser scanning and triangulation
device such as a Micro-Epsilon.RTM. gapCONTROL laser scanner. This
device emits a fan-shaped laser beam toward a gap area, and
receives diffuse reflection thereof into a sensor that is separated
from the emitter for triangulation. From the reflected line image
produced by the beam, software triangulates the distance of the gap
from the sensor, identifies the gap, and determines the gap
width
[0012] FIG. 3 shows a distal arm 69 connected to an upper arm 56 of
the inspection scope by a pivot joint 64 that is robotically
controlled by an actuator 63 operating against an offset point 65
relative to a main pivot axis 67. In addition, the distal arm 69
may be robotically rotated 73 via a rotary coupling 86. This may be
done for example by means of a hollow stepper motor 80 with a
powered stator 81 in the rotary coupling 86 and an unpowered rotor
83 driving a shaft 84 on which is mounted the distal arm 69.
Alternately, other robotic pivot and rotation means may be used as
known in robotics. The gap measuring device 52 may be mounted on
the distal end 79 of the distal arm at a predetermined angle for
the laser beam 61 to intersect the gap 59. The above pivot and
rotation features provide orientation of the optical axes of the
laser emitter 55 and receiver 57 relative to the gap 59. The
measuring device 52 is shown here in a schematic side sectional
view for clarity. This orients the fan-shaped laser beam 61 in a
plane normal to the page. In practice, the laser beam 61 may be
oriented in the plane of the page as later shown so that the
reflected laser line crosses the gap 59 transversely. The gap
measuring device 52 is navigated along a path that extends through
the exit end 35 of the transition duct 34 to a position that
impinges the laser across the gap 59. The measuring device may be
positioned between two vanes 38A as shown, or it may be positioned
just ahead of the vanes such that the laser beam 61 is directed
between the vanes. On some gas turbines the first row of turbine
airfoils is the circular array of blades, not vanes. In such a
design the transition duct exit is largely circumferentially
oriented, eliminating the need for vanes ahead of the first row of
blades.
[0013] A method for measuring the gap 59 includes inserting the
inspection scope 56, 69 into an inspection port 58 (FIG. 2) of the
engine 20; and navigating the measuring device 52 to a position
proximate the tip of a blade 40A on the turbine. From this position
the gap identification and measuring device 52 identifies and
measures the gap 59. This process may be repeated by turning the
turbine disk 37 to position the tip of a second blade proximate the
distal end of the inspection scope. From this position the gap
identification and measurement device 52 identifies and measures
the gap between the second blade tip and the surrounding gas path
shroud. This may be repeated successively for all of the remaining
blades to measure the gap 59 for each blade tip at a given turbine
position, such as at top center. Each measurement may be stored in
the computer 68.
[0014] A technician may operate the computer interactively to
navigate the inspection scope into a gap-measuring position. During
such navigation the computer may store articulations and/or
coordinates of the inspections cope to define a navigation path.
The computer may subsequently repeat this predetermined navigation
path automatically to position the distal end of the inspection
scope.
[0015] FIG. 4 shows an embodiment of the distal arm 69' of the
inspection scope with an additional pivot joint 88 that pivots an
attachment bracket 89 holding the measuring device 52. Here the
measuring device 52 is rotated 90 degrees compared to the view of
FIG. 3 to illustrate the fan-shaped laser beam 61 that produces a
reflected line transversely crossing the gap 59. The additional
pivot joint 88 provides additional flexibility for reaching the
measuring position and obtaining an optimum angle of the laser beam
61. A camera 53 such as a USB camera may be attached to the
measuring device 52 or the attachment bracket 89 for visual
navigation. One or more temperature sensors such as a thermocouple
or infrared camera 54 may be attached to the measuring device 52 to
sense the temperature of the shroud 44 and of each blade 40A in the
proximate position thereof to determine gap width for each blade at
the measured position as a function of temperature.
[0016] A method in accordance with an embodiment of the invention
allows the blade tip-to-shroud gap(s) to be measured without
separating the halves of the engine casing, thereby providing an
accurate measurement of the gap width as it exists in-situ.
Moreover, the gap(s) may be measured while the engine is on turning
gear and is being cooled from an operating temperature to ambient
following shutdown of the engine.
[0017] FIG. 5 is a transverse sectional view of a turbine disk 37
in a turbine section 26. Multiple inspection scopes may be inserted
in respective inspection ports at different azimuths, such as two
or more of 0, 90, 180, and 270 degrees around the turbine disk to
measure a respective gap 59A-D for each blade tip at multiple
rotational positions. For example the gaps may be measured at the
top (0.degree.) and bottom (180.degree.) of the turbine, or the
top, bottom, and opposite sides (90.degree., 270.degree.) of the
turbine disk. Neither the upper half casing 90A nor the lower half
casing 90B of the turbine section 26 must be removed for the
inspection. With the present invention, measuring the gaps between
the tips of the first row of turbine blades 40A and the surrounding
gas path shroud 44 can be done in-situ with the engine fully
assembled except for removal of one or more pilot fuel nozzles.
[0018] While various embodiments of the present invention have been
shown and described herein, it will be obvious that such
embodiments are provided by way of example only. Numerous
variations, changes and substitutions may be made without departing
from the invention herein. Accordingly, it is intended that the
invention be limited only by the spirit and scope of the appended
claims.
* * * * *