Patent Description:
Gas turbine engines employed on an aircraft vehicle include a variety of internal components or airfoil components such as, for example, turbine blades and turbine vanes. The turbine blades and vanes can include internal cooling passages, which are frequently exposed to hot temperature environments that can contain rich oxygen levels and moisture. Continuous exposure to these environmental conditions can lead to corrosion of the internal walls of the cooling passages. This internal passage corrosion decreases the thickness of non-corroded wall portions and reduces the overall integrity of blades and/or vanes.

<CIT> discloses a method and a device for measuring a defect of a member made of magnetic material and an inspection probe for use in measurement of the defect.

<CIT> discloses a pipe casing inspection system that combines sensor information including magnetic flux leakage from high resolution vertilog tools and multi finger caliper measurements.

<CIT> discloses a method of inspecting components of a gas turbine in order to be able to detect non-destructively the corrosion on the inner surface of a hollow blade.

<NPL>en, discloses a portable magnetoscop measuring instrument.

According to a first aspect of the invention, a magnetoscop inspection system and turbine component as described by claim <NUM> is provided.

According to a second aspect of the invention, a method is provided to inspect a turbine component as described by claim <NUM>.

The following descriptions are provided by way of example only and should not be considered limiting in any way.

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the figures.

Turbine blades and/or vanes employed in gas turbine engines typically include various materials (e.g., nickel) susceptible to corrosion. The internal corrosion of turbine blades and/or vanes, can cause depletion of pure nickel (Ni) from a base metal alloy, and in turn can causes the deposition of corrosion byproducts such nickel oxide (NiO), cobalt oxide (CoO), etc., on the internal wall(s) of the corroding component.

Corrosion byproducts (e.g., NiO, CoO, etc.) typically have ferromagnetic properties, which can be sensed by magnetoscop devices. Therefore, a computer generated image of the component's internal profile can be produced using various computed tomography (CT) techniques. For example, magnetoscops are capable of measuring the magnetic flux density and relative permeability within the scope of the quality control of stainless steel and low-permeable (non-magnetic) alloys as well as the localization of ferrite enclosures. Magnetoscops can also detect changes in material (sulfidation, degradation of lamination, structural changes) based on permeability comparative measurements. However, the internal turbine internal components (e.g., blades and vanes) have complex geometries and profiles. Turbine blades, for example, have an airfoil profile that includes both convex portions and concave portions. Consequently, attempts to inspect the internal wall of a turbine blade using only a magnetoscop can result in inaccurate measurements due to separations or boundaries between the concave portions and convex portions.

Various non-limiting embodiments described herein provide a magnetoscop inspection system that includes a robotically controlled magnetoscop and a profile boundary controller. The robotically controlled magnetoscop includes a probe capable of scanning a turbine component (e.g., turbine blade) to detect a plurality of inspection points that define the inner-wall profile. The profile boundary controller analyzes the inspection points in combination with a physics-based model to determine different inner-wall profiles (e.g., concave profiles versus convex profiles) of a turbine engine component (e.g., a turbine blade), along with detecting boundaries between the different inner-wall profiles. In at least one non-limiting embodiment, the profile boundary controller analyzes neighborhood inspection points corresponding to a corroded portion(s) of the inner-wall, along with the CT wall thickness reading to calculate not only the thickness of the corrosion layer but also thicknesses of remaining non-corroded portions of the inner-wall.

With reference now to <FIG>, a gas turbine engine <NUM> is schematically illustrated according to a non-limiting embodiment.

The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate via bearing systems <NUM> about the engine central longitudinal axis (A) which is collinear with their longitudinal axes.

In one disclosed embodiment, the engine <NUM> bypass ratio is greater than about ten (<NUM>:<NUM>), the fan diameter is significantly larger than that of the low pressure compressor <NUM>, and the low pressure turbine <NUM> has a pressure ratio that is greater than about five (<NUM>:<NUM>). The geared architecture <NUM> may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about <NUM>:<NUM>. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

The fan section <NUM> of the engine <NUM> is designed for a particular flight condition--typically cruise at about <NUM> Mach and about <NUM>,<NUM> feet (<NUM>,<NUM> meters).

Turning to <FIG>, a magnetoscop scanning inspection system <NUM> configured to inspect internal corrosion of a turbine blade <NUM> is illustrated according to a non-limiting embodiment. The turbine blade <NUM> includes a distal end <NUM>, which is coupled to a rotor <NUM> of a turbine engine. Although a turbine blade <NUM> is illustrated as an example, the magnetoscop inspection system <NUM> is capable of scanning other turbine engine components or airfoil components such as, for example, a turbine vane.

A cross-section of the turbine blade <NUM> is illustrated in <FIG>. The turbine blade <NUM> includes hollow cooling passages <NUM> defined by a pressure-side wall <NUM> and a suction-side wall <NUM>. The cooling passages <NUM> pass cool air therethrough as the pressure-side wall <NUM> and the suction-side wall <NUM> are exposed to heated core gas flow. A plurality of ribs <NUM> extend between the pressure-side wall <NUM> and the suction-side wall <NUM> to define each individual internal cooling passage <NUM>.

<FIG> is a close-up view of an internal section <NUM> of the turbine blade <NUM> including one of the cooling passages <NUM>. The internal cooling passages <NUM> is bounded by an opposing pair of ribs <NUM>, each which extends between the pressure-side wall <NUM> and the suction-side wall <NUM>. The pressure-side wall <NUM> includes an outer pressure-side wall surface <NUM> and an inner pressure-side wall surface <NUM>. Similarly, the suction-side wall <NUM> includes an outer suction-side wall surface <NUM> and an inner suction-side wall surface <NUM>. The pressure-side wall <NUM> has a first corroded element <NUM> formed thereon, while the suction-side wall <NUM> has a second corroded element <NUM> formed thereon. These corroded elements <NUM> and <NUM> have ferromagnetic properties, which can be detected and analyzed by the magnetoscop scanning inspection system <NUM>.

Referencing again <FIG>, the magnetoscop scanning inspection system <NUM> includes a magnetoscop <NUM>, a magnetoscop controller <NUM>, and a graphic user interface (GUI) <NUM>. The magnetoscop <NUM> is configured to scan a pressure-side surface 200a of the turbine blade <NUM> (see <FIG>) and an opposing suction-side surface 200b of the turbine blade <NUM> (see <FIG>). The magnetoscop <NUM> can be supported by a one or more robotically controlled mechanisms (not shown). The GUI <NUM> can display measurements, images, and/or analyzed results obtained from inspecting a turbine component. The GUI <NUM> can also receive various inputs, models, and/or commands for controlling the magnetoscop <NUM>.

The magnetoscop controller <NUM> can include a robotic control unit <NUM> that controls the operation of the robotic support mechanisms to facilitate autonomous scanning of the turbine blade <NUM>. The robotic control unit <NUM> is also configured to actively adjust a position the magnetoscop <NUM> at a controlled orientation relative to the turbine blade <NUM> such that probe <NUM> is maintained at a set distance (D) away from the pressure-side surface 200a and the suction-side surface 200b. In this manner, the probe <NUM> can be prevented from scrapping directly against the surfaces 200a, 200b of the turbine blade <NUM>, which in turn prevents damaging the probe <NUM> and scraping the turbine blade <NUM>.

In at least one non-limiting embodiment, the magnetoscop inspection system <NUM> can inspect and analyze the permeability from the perspective of the pressure-side surface 200a and the suction-side surface 200b of the turbine blade <NUM>. The results (e.g., detected magnetic flux permeability) can be compared with a threshold value to determine a structural integrity of the turbine blade <NUM>. If the structural integrity of the turbine blade <NUM> is compromised then the turbine blade <NUM> may be overhauled or replaced. Accordingly, detecting permeability through the surfaces 200a, 200b can improve results of the inspection process.

The magnetoscop controller <NUM> further includes a CT unit <NUM> and corrosion model unit <NUM>. Any one of the robotic control unit <NUM>, the CT unit <NUM>, and the corrosion model unit <NUM> can be constructed as an electronic hardware controller that includes memory and a processor configured to execute algorithms and computer-readable program instructions stored in the memory. In addition, the robotic control unit <NUM>, the CT unit <NUM>, and the corrosion model unit <NUM> can all be embedded or integrated in a single sub-controller.

While scanning the pressure-side and suction-side surfaces 200a, 200b of the turbine blade <NUM>, the measured inspection points are fedback to the magnetoscop controller <NUM>. Based at least in part on the permeability at the measured inspection points, the CT unit <NUM> generates a CT profile of the current state of the internal cooling passage <NUM>. The current CT profile of the internal cooling passage <NUM> indicates the thicknesses of the pressure-side wall <NUM> and the suction-side wall <NUM> (see <FIG>).

The corrosion model unit <NUM> can store one or more available reference CT profiles corresponding to a given known turbine component (e.g., turbine blade, turbine vane, etc.). <FIG> illustrates an example of a reference CT model <NUM> including an ideal cooling passage <NUM>, which corresponds to the current measured CT profile <NUM> of the cooling passage <NUM> shown in the close-up section <NUM> illustrated in <FIG>. Accordingly, the magnetoscop inspection system <NUM> can utilize the current measured CT profile <NUM> of the cooling passage <NUM> along with the corresponding reference CT reference profile <NUM> including the ideal cooling passage <NUM> to calculate the thickness of the corrosion elements <NUM>, <NUM>, along with the thickness of remaining non-corrosion portions (DY1, DY2) of the inner wall surfaces <NUM>, <NUM> (see <FIG>).

For example, a given turbine component, a particular instance (e.g., unique serial number) of the turbine component, or portion of the turbine component (e.g., an internal cooling passage of the turbine component) can be inspected prior to being made available for field operation, i.e., prior to being employed in a turbine engine for first time use. Accordingly, a reference CT profile <NUM> can be generated which indicates an expected or known profile of the internal cooling passage (i.e., an ideal cooling passage <NUM>) of the given turbine component or the particular instance (e.g., unique serial number) of the turbine part, along with the expected or known thicknesses (DREF1, DREF2, DREFn) of the pressure-side wall <NUM> and suction-side wall <NUM> prior to corrosion.

The corrosion model unit <NUM> can utilize a stored reference CT profile (e.g., reference CT profile <NUM>) corresponding to the component currently scanned to accurately inspect and analyze the current profile of scanned component. In at least one embodiment, the corrosion model unit <NUM> can receive an input (e.g., component identification (ID)) via the GUI <NUM> indicating the type of turbine blade <NUM>, particular instance (e.g., unique serial number) of the turbine component, etc., currently undergoing inspection. Based on the indicated turbine blade <NUM>, the corrosion model unit <NUM> can obtain a corresponding reference CT profile from memory, and can compare the reference CT profile to the current measured CT profile generated from the measured inspection points that are fedback from the magnetoscop <NUM>.

For example, the corrosion model unit <NUM> can obtain the reference CT profile <NUM> (see <FIG>) corresponding to the current measured CT profile of the internal section <NUM> of the turbine blade <NUM> (see <FIG>). Accordingly, the corrosion model unit <NUM> can calculate thicknesses of the remaining non-corroded portions of the pressure-side wall <NUM> and the suction-side wall <NUM>. In this example, the thickness of the remaining non-corroded portions of the pressure-side wall <NUM> can be determined as distance (DY1) between the outer pressure-side wall surface <NUM> and the first corrosion element <NUM>. Similarly the remaining non-corroded portions of the suction-side wall <NUM> can be determined as distance (DY2) between the outer suction-side wall surface <NUM> and the second corrosion element <NUM>. The corrosion model unit <NUM> can also calculate the thickness (DX1, DX2) of the first and second corrosion elements <NUM> and <NUM>, respectively.

In one or more embodiments, the thickness (DY1) of the remaining non-corroded portions (e.g., of the pressure-side wall <NUM>) can be determined by subtracting the thickness of the adjacent corrosion element <NUM> from the known thickness (e.g., DREF1) of the pressure-side wall <NUM>, i.e., DY1 = DREF1 - DX1.

In one or more non-limiting embodiments, the magnetoscop scanning inspection system <NUM> can utilize the measured distances to determine the structural integrity of a turbine component, e.g., the turbine blade <NUM>. For example, the corrosion model unit <NUM> can compare the thickness of the remaining non-corroded portions (e.g., DY1, DY2, etc.) to a distance threshold and/or can compare the corrosion element thicknesses (DX1, DX2, etc.) to a thickness threshold. When the wall thickness (e.g., DY1, DY2, etc.) and/or the corrosion element thickness (DX1, DX2, etc.) exceed their respective threshold, the corrosion model unit <NUM> can determine the component (e.g., turbine blade <NUM>) is faulty, and generate an alert on the GUI <NUM>. Accordingly, the component can be disposed of or destroyed to prevent it from being placed back into the field.

While the present invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from the essential scope thereof.

Claim 1:
A magnetoscop inspection system (<NUM>) and a turbine component, the magnetoscop inspection system comprises:
a magnetoscop (<NUM>) configured to measure a permeability at a plurality of inspection points of the turbine component (<NUM>);
a computed tomography (CT) unit (<NUM>) configured to generate a measured profile (<NUM>) of a hollowed portion of the turbine component based at least in part on the permeability at the measured inspection points; and
a corrosion model unit (<NUM>) configured to store in memory at least one reference CT profile (<NUM>) corresponding to a given known turbine component,
wherein:
the magnetoscop inspection system is configured to determine a structural integrity of the turbine component based on a comparison between the measured profile (<NUM>) and a reference CT profile (<NUM>) corresponding to the turbine component;
the turbine component is a turbine blade (<NUM>), and the measured profile (<NUM>) is a profile of an internal cooling passage (<NUM>) contained in a hollowed portion of the turbine blade;
the measured profile (<NUM>) further includes a pressure-side wall (<NUM>) and the suction-side wall (<NUM>), the pressure-side wall and the suction-side wall each including an outer wall surface (<NUM>, <NUM>) and an inner wall surface (<NUM>, <NUM>), and
the corrosion model unit (<NUM>) is configured to determine one or both of a thickness of at least one corrosion element (<NUM>, <NUM>) located in the internal cooling passage (<NUM>) and a thickness of non-corroded wall portions of the turbine blade based at least in part on comparison between the measured profile (<NUM>) and the reference CT profile (<NUM>).