METHOD FOR REDUCING DAMAGE TO A COMPONENT OF A GAS TURBINE ENGINE

Abstract

A method includes: determining first atmospheric agents that are predicted to be ingested by a gas turbine engine during operation in a predefined route of an aircraft and their composition, particle size, and concentration; determining a composition and an amount of a predicted deposit that is predicted to form on the component based on the composition, the particle size, and the concentration of the first atmospheric agents; determining a predicted damage to the component based at least on the composition and the amount of the predicted deposit and a composition of a coating of the component; determining locations at which second atmospheric agents are present in air that reduce the predicted damage to the component and their composition, particle size, and concentration; determining an alternative route including the locations; and operating the gas turbine engine at the locations in the alternative route.

Claims

1. A method for reducing damage to a component of a gas turbine engine of an aircraft, the component having a substrate and a coating disposed on the substrate, the method comprising the steps of: determining one or more first atmospheric agents present in air that are predicted to be ingested by the gas turbine engine during operation in a predefined route of the aircraft; determining a composition, a particle size, and a concentration of the one or more first atmospheric agents in the air at the predefined route; determining a composition and an amount of a predicted deposit that is predicted to form on the component, due to the operation of the gas turbine engine in the predefined route, based on the composition, the particle size, and the concentration of the one or more first atmospheric agents in the air at the predefined route; determining a predicted damage to the component based at least on: the composition and the amount of the predicted deposit; and a composition of the coating of the component; determining one or more locations at which one or more second atmospheric agents are present in air that reduce the predicted damage to the component; determining a composition, a particle size, and a concentration of the one or more second atmospheric agents in the air at the one or more locations; determining an alternative route for the aircraft based on the composition, the particle size, and the concentration of the one or more second atmospheric agents in the air at the one or more locations, the alternative route comprising the one or more locations, wherein the alternative route is different from the predefined route; and operating the gas turbine engine in the alternative route of the aircraft, such that the gas turbine engine is operated at the one or more locations.

2. The method of claim 1, wherein the gas turbine engine is operated in the alternative route after a predetermined number of cycles of operation in the predefined route.

3. The method of claim 1, further comprising determining a composition and an amount of a pre-existing deposit formed on the component, wherein the predicted damage is further determined based on the composition and the amount of the pre-existing deposit.

4. The method of claim 3, further comprising changing one or more operating parameters of the gas turbine engine, such that an operating temperature of the gas turbine engine reduces to below melting temperatures of the predicted deposit and the pre-existing deposit.

5. The method of claim 1, wherein determining the predicted damage is further based on: a thickness of the coating of the component; and a composition of the substrate of the component.

6. The method of claim 5, wherein determining the predicted damage is additionally based on at least one of: a tortuosity of the coating; a porosity of the coating; a thermal conductivity of the coating; and a method of deposition of the coating.

7. The method of claim 1, wherein the one or more first atmospheric agents comprise at least one of calcium, magnesium, aluminium, silicon, sulphur, oxygen, hydrogen, carbon, sodium, and chlorine.

8. The method of claim 1, wherein the one or more first atmospheric agents and the composition, the particle size, and the concentration of the one or more first atmospheric agents in the air are determined via at least one of a meteorological database and a meteorological model.

9. The method of claim 1, wherein the one or more second atmospheric agents and the composition, the particle size, and the concentration of the one or more second atmospheric agents in the air are determined via at least one of a meteorological database and a meteorological model.

10. The method of claim 1, wherein the one or more second atmospheric agents react with the predicted deposit to change at least one of a thermochemical property and a thermomechanical property of the predicted deposit so as to reduce the predicted damage to the component.

11. The method of claim 1, where the second atmospheric agent comprises at least one of CaO, MgO, Al.sub.2O.sub.3, SiO.sub.2, FeO, Fe.sub.2O.sub.3, K.sub.2O, Na.sub.2O.

12. The method of claim 11, where the second atmospheric agent comprises at least one of dolomite, calcite, quartz, plagioclase feldspar, alkali feldspar, mica, clay, gypsum, halite, hematite.

13. An aircraft including a gas turbine engine, wherein the gas turbine engine is operated according to the method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Embodiments will now be described by way of example only, with reference to the FIGS, in which:

[0035] FIG. 1 is a sectional side view of a gas turbine engine;

[0036] FIG. 2 is a schematic cross-sectional view of a component of a gas turbine engine in accordance with an embodiment of the present disclosure;

[0037] FIG. 3 is a flowchart depicting various steps of a method for reducing damage to the component in accordance with an embodiment of the present disclosure; and

[0038] FIG. 4 is a graph depicting various routes of an aircraft in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0039] Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying FIGS. Further aspects and embodiments will be apparent to those skilled in the art.

[0040] FIG. 1 illustrates a gas turbine engine 10 having a principal rotational axis 9. The engine 10 comprises an air intake 12 and a propulsive fan 23 that generates two airflows: a core airflow A and a bypass airflow B. The gas turbine engine 10 comprises a core 11 that receives the core airflow A. The engine core 11 comprises, in axial flow series, a low pressure compressor 14, a high pressure compressor 15, combustion equipment 16, a high pressure turbine 17, a low pressure turbine 19, and a core exhaust nozzle 20. A nacelle 21 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass exhaust nozzle 18. The bypass airflow B flows through the bypass duct 22. The fan 23 is attached to and driven by the low pressure turbine 19 via a shaft 26 and an epicyclic gearbox 30.

[0041] In use, the core airflow A is accelerated and compressed by the low pressure compressor 14 and directed into the high pressure compressor 15 where further compression takes place. The compressed air exhausted from the high pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture is combusted. The resultant hot combustion products then expand through, and thereby drive, the high pressure and low pressure turbines 17, 19 before being exhausted through the core exhaust nozzle 20 to provide some propulsive thrust. The high pressure turbine 17 drives the high pressure compressor 15 by a suitable interconnecting shaft 27. The fan 23 generally provides the majority of the propulsive thrust. The epicyclic gearbox 30 is a reduction gearbox.

[0042] Note that the terms low pressure turbine and low pressure compressor as used herein may be taken to mean the lowest pressure turbine stages and lowest pressure compressor stages (i.e., not including the fan 23) respectively and/or the turbine and compressor stages that are connected together by the interconnecting shaft 26 with the lowest rotational speed in the engine (i.e., not including the gearbox output shaft that drives the fan 23). In some literature, the low pressure turbine and low pressure compressor referred to herein may alternatively be known as the intermediate pressure turbine and intermediate pressure compressor. Where such alternative nomenclature is used, the fan 23 may be referred to as a first, or lowest pressure, compression stage.

[0043] Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of interconnecting shafts. By way of further example, the gas turbine engine 10 shown in FIG. 1 has a split flow nozzle 18, 20 meaning that the flow through the bypass duct 22 has its own nozzle 18 that is separate to and radially outside the core exhaust nozzle 20. However, this is not limiting, and any aspect of the present disclosure may also apply to engines in which the flow through the bypass duct 22 and the flow through the core 11 are mixed, or combined, before (or upstream of) a single nozzle, which may be referred to as a mixed flow nozzle. One or both nozzles (whether mixed or split flow) may have a fixed or variable area. Whilst the described example relates to a turbofan engine, the disclosure may apply, for example, to any type of gas turbine engine, such as an open rotor (in which the fan stage is not surrounded by a nacelle) or turboprop engine, for example. In some arrangements, the gas turbine engine 10 may not comprise a gearbox 30.

[0044] The geometry of the gas turbine engine 10, and components thereof, is defined by a conventional axis system, comprising an axial direction (which is aligned with the rotational axis 9), a radial direction (in the bottom-to-top direction in FIG. 1), and a circumferential direction (perpendicular to the page in the FIG. 1 view). The axial, radial, and circumferential directions are mutually perpendicular.

[0045] FIG. 2 shows a schematic cross-sectional view of a component 100 of a gas turbine engine (e.g., the gas turbine engine 10 of FIG. 1) in accordance with an embodiment of the present disclosure.

[0046] The component 100 may operate at high temperatures, which may be greater than about 1000 C., greater than about 1500 C., or greater than about 1600 C. Examples of the component 100 include, but are not limited to, seal segments, shrouds, combustion tubes, blade tracks, disc assemblies, aerofoils (e.g., blades or vanes), combustion chamber liners, and the like, of the gas turbine engine.

[0047] The component 100 includes a substrate 102 and a coating 104 disposed on the substrate 102. In some examples, the substrate 102 may include a metal alloy (e.g., a superalloy). Examples of metal alloys include, but are not limited to, Si-containing metal alloys such as molybdenum-silicon alloys (e.g., MoSi.sub.2) and niobium-silicon alloys (e.g., NbSi.sub.2), or a superalloy based on nickel (Ni), cobalt (Co), nickel/iron (Ni/Fe), or the like.

[0048] In some other examples, the substrate 102 may include a ceramic matrix composite (CMC). The CMC may include any ceramic matrix material, including, for example, silicon carbide, silicon nitride, alumina, silica, and the like. The CMC may further include any desired filler material, and the filler material may include a continuous reinforcement or a discontinuous reinforcement. For example, the filler material may include discontinuous whiskers, platelets, or particulates. As another example, the filler material may include a continuous monofilament or multifilament weave.

[0049] The coating 104 may be a thermal barrier coating (TBC), an environmental barrier coating (EBC), and the like. The coating 104 may be selected based on the substrate 102 and its composition, and application requirements of the component 100. Further, the coating 104 has a thickness 115. The thickness 115 of the coating 104 may also depend upon the application requirements of the component 100. For example, in some cases, the thickness 115 may be proportional to a temperature at which the component 100 operates. In some embodiments, the coating 104 may define a surface 101 of the component 100. The surface 101 may be an outer surface of the component 100.

[0050] While not shown in FIG. 2, the component 100 may further have a bond coat (not shown) disposed between the substrate 102 and the coating 104. The bond coat may improve a bonding between the substrate 102 and the coating 104.

[0051] The gas turbine engine including the component 100 may ingest one or more first atmospheric agents (e.g., mineral dust, volcanic ash, etc.) during operation. As a result, various deposits may form on the component 100, or more specifically, the surface 101 of the component 100. Such deposits may form a melt during operation of the gas turbine engine, and consequently may damage the component 100. Specifically, the melt formed from the deposits may damage the coating 104, and in some cases, may further damage the substrate 102 of the component 100. As used herein, the term melt refers to a deposit in its molten phase.

[0052] In the illustrated embodiment of FIG. 2, the deposits formed on the component 100 include a predicted deposit 110 and a pre-existing deposit 112. As used herein, the term predicted deposit refers to a deposit that is predicted to form on the component 100 during operation of the gas turbine engine on a specific route. Further, the term pre-existing deposit refers to a deposit that is already formed on the component 100 due to prior operation of the gas turbine engine on a specific route. The predicted deposit 110 and the pre-existing deposit 112 will now be discussed in greater detail with reference to FIG. 3.

[0053] FIG. 3 shows a flowchart depicting various steps of a method 200 for reducing damage to a component (e.g., the component 100 of FIG. 2) of a gas turbine engine (e.g., the gas turbine engine 10 of FIG. 1) of an aircraft in accordance with an embodiment of the present disclosure. In some embodiments, one or more steps of the method 200 may be carried out by a processor.

[0054] The method 200 will be discussed with reference to the gas turbine engine 10 of FIG. 1 and the component 100 of FIG. 2. However, the method 200 may also be implemented with gas turbine engines having other suitable engine configurations. FIG. 4 shows a graph 300 depicting various routes between two locations. The method 200 will also be explained with further reference to FIG. 4.

[0055] At step 202, the method 200 includes determining one or more first atmospheric agents present in air that are predicted to be ingested by the gas turbine engine during operation in a predefined route of the aircraft. Referring to FIG. 1, for example, the method 200 may include determining one or more first atmospheric agents that are predicted to be ingested by the gas turbine engine 10 during operation in a predefined route of an aircraft including the gas turbine engine 10.

[0056] As used herein, the term predefined route refers to a pre-planned route between a first location and a second location that an aircraft operates in to move from the first location to the second location. In some cases, a predefined route may be a least distance route between the first and second locations.

[0057] As used herein, the term atmospheric agent refers to any atmospheric agent that can participate in and/or catalyse formation of deposits that can form melts and potentially damage a component on which the deposits are formed. For example, an atmospheric agent may include mineral dust, a mixture of various different mineral dusts, volcanic ash, and so forth.

[0058] Therefore, the one or more first atmospheric agents may include mineral dust, a mixture of various different mineral dusts, volcanic ash, sulphur/sulphate gases, water, and any other atmospheric agents that can participate in and/or catalyse formation of deposits that can form melts and potentially damage the component.

[0059] The one or more first atmospheric agents may include at least one of calcium, magnesium, aluminium, silicon, sulphur, oxygen, hydrogen, carbon, sodium, and chlorine. For example, volcanic ash and mineral dust may contain calcium, magnesium, aluminium, silicon, sulphur, iron, and the like. Furthermore, in some cases, the one or more first atmospheric agents may include sodium and chlorine in the form of sodium chloride (NaCl).

[0060] The one or more first and one or more second atmospheric agents may comprise natural aerosols and/or gases, such as volcanic ash, volcanic glass, volcanic gas, mineral dust, mineral sand, water, ice, sea salt, anthropogenic pollutant gases.

[0061] Mineral dusts, mineral sands and volcanic ash may comprise crystalline minerals and amorphous material including glasses derived from geological melts. Examples of these crystalline minerals are, but are not limited to, clay group minerals (e.g., smectites), mica group minerals (e.g., muscovite, phlogopite), feldspars (e.g., alkali feldspars such as albite; plagiosclase feldspar), carbonates (e.g., calcite, dolomite), sulfates (e.g., anhydrite, gypsum) and silica minerals (e.g., quartz).

[0062] As will be described in greater detail below, the one or more first atmospheric agents that are predicted to be ingested by the gas turbine engine during operation in the predefined route of the aircraft may be determined meteorologically.

[0063] Referring to FIG. 4, for example, an aircraft 50 (shown schematically as a block) including the gas turbine engine 10 may operate between a first location FL and a second location SL via a predefined route RD. The first location FL and the second location SL may be locations of airports between which the aircraft 50 generally operates via the predefined route RD. In this example, the predefined route RD includes a location L1 and a location L2. It may be noted that the predefined route RD may include any number of locations. However, for explanatory purposes, it may be assumed that the location L1 and the location L2 include significant amount of atmospheric agents. Thus, the one or more first atmospheric agents that are predicted to be ingested by the gas turbine engine 10 during operation in the predefined route RD of the aircraft 50 may be assumed to be one or more of the atmospheric agents in air at the location L1 and the location L2.

[0064] At step 204, the method 200 further includes determining a composition, a particle size, and a concentration of the one or more first atmospheric agents in the air at the predefined route. Referring now to FIG. 4, for example, the method 200 may include determining a composition, a particle size, and a concentration of the one or more first atmospheric agents in the air at the predefined route RD. Specifically, in this example, the method 200 may include determining a composition, a particle size, and a concentration of the one or more first atmospheric agents in the air at the location L1 and the location L2.

[0065] In some examples, cumulative concentration of the one or more first atmospheric agents may be used to establish a damage threshold to the component.

[0066] In some embodiments, the one or more first atmospheric agents and the concentration of the one or more first atmospheric agents in the air are determined via at least one of a meteorological database and a meteorological model.

[0067] As used herein, the term meteorological refers to the scientific study of Earth's atmosphere and its changes, used especially in predicting what the weather will be like, and the particle size, chemical composition, and concentration of atmospheric agents.

[0068] As used herein, the term meteorological database refers to a large-scale database which stores meteorological data of a location/site that is acquired by various monitoring devices (e.g., satellites, sensors, radar, and so forth). The meteorological database may include historical meteorological data as well as predicted/forecasted meteorological data of the location/site, such as composition of air, wind speed and direction at various altitudes, humidity, sunlight intensity, pressure, precipitation (e.g., rain, snow, hail), pollution, wildfires, dust storms, salt spray, transport of particulate matter and volcanic ash, distribution of corrosion gases, and other meteorological parameters.

[0069] As used herein, the term meteorological model refers to a mathematical or a computational model that forecasts meteorological data of a location/site. In other words, a meteorological model may predict future meteorological data of the location/site based upon current and historical meteorological data of the location/site. A meteorological model may receive input data from a meteorological database and provide a forecast output based on the input data. The forecast output may also be stored in the meteorological database.

[0070] For example, the one or more first atmospheric agents and the composition, the particle size, and the concentration of the one or more first atmospheric agents present in the air may be determined based on the meteorological data taken from the World Health Organisation (WHO), the Met Office's Numerical Atmospheric-dispersion Modelling Environment (NAME), Quantitative Volcanic Ash (QVA) models, European Centre for Medium-Range Weather Forecasts (ECMWF), and the like.

[0071] As an example, for a given latitude, longitude, altitude, and time, the determined meteorological data from steps 202 and 204 may include: a sediment composition (in wt. %) of: Na.sub.2O=5.72, CaO=29.76, MgO=14.09, Al.sub.2O.sub.3=8.21, SiO.sub.2=35.18, FeO=4.53, K.sub.2O=1.85, TiO.sub.2=0.66; average relative humidity of 25%; average wind speed of 33 kilometres per hour (km/h); average pressure of 1017.9 millibars (mb); and average airborne mineral dust concentration of 1 microgram per metre cube (g/m.sup.3).

[0072] At step 206, the method 200 further includes determining a composition and an amount of a predicted deposit that is predicted to form on the component, due to the operation of the gas turbine engine in the predefined route, based on the composition, the particle size, and the concentration of the one or more first atmospheric agents in the air at the predefined route. Referring to FIGS. 2 and 4, for example, the method 200 may include determining a composition and an amount of the predicted deposit 110 that is predicted to form on the component 100, due to the operation of the gas turbine engine 10 in the predefined route RD (see FIG. 4), based on the composition, the particle size, and the concentration of the one or more first atmospheric agents in the air at the predefined route RD.

[0073] In some examples, determining the composition of the predicted deposit may further include determining thermochemical and thermophysical properties of the predicted deposit. In some examples, determining the amount of the predicted deposit may further include determining a thickness of the predicted deposit. In some examples, the composition and the amount of the predicted deposit may be determined further based on operating parameters of the gas turbine engine.

[0074] In some embodiments, the method 200 may further include determining a composition and an amount of a pre-existing deposit formed on the component. Referring to FIG. 2, for example, the method 200 may include determining a composition and an amount of the pre-existing deposit 112 formed on the component 100.

[0075] The composition and the amount of the pre-existing deposit may be measured by techniques such as, in-situ Raman spectroscopy, in-situ Low Energy Electron Diffraction (LEED), in-situ Laser Induced Breakdown Spectroscopy (LIBS), borescoping, deposit sampling, compositional analysis (e.g., X-Ray Diffraction), or by using a computational model.

[0076] The composition and amount of the predicted deposit (e.g., the predicted deposit 110 of FIG. 2) may be determined as a product of systematic, codified relationships between the concentration of the one or more first atmospheric agents and the composition and the amount of the pre-existing deposit, if present.

[0077] An example of such relationships include fractionation of the one or more first atmospheric agents as they travel through the gas turbine engine, and an amount of a deposit that forms from fractionated constituents of each of the one or more first atmospheric agents. The term fractionation of the one or more first atmospheric agents refers to a process of separating the constituents of each of the one or more first atmospheric agents based on a specific property, for example, particle size, composition, and the like. The amount of the predicted deposit that forms from the fractionated constituents of each of the one or more first atmospheric agents may be calculated by using computational models, such as a turbine deposition and accretion model.

[0078] Fractionation of the one or more first atmospheric agents may be a function of core dust dose values (in mg/m.sup.3), which may be calculated, for example, using a computational model at any location, any time, and over any three-dimensional space using data from the European Centre for Medium-Range Weather ForecastsCopernicus Atmosphere Monitoring Service (ECMWF-CAMS).

[0079] Fractionation of the one or more first atmospheric agents may further be a function of thermal and fluid dynamic parameters of the gas turbine engine at a specific thrust rating. The thermal and fluid dynamic parameters may be determined using computational models, such as performance and air systems models.

[0080] Fractionation of the one or more first atmospheric agents may further be a function of earlier deposition of dust constituents on other components of the gas turbine engine that are upstream of the component. This may be calculated using computational models such as deposition and accretion models.

[0081] Fractionation of the one or more first atmospheric agents may further be a function of reactivity and stability of the constituents of the one or more first atmospheric agents under a temperature profile within an engine core (e.g., the engine core 11 of FIG. 1) of the gas turbine engine. This may be calculated from the composition of each of the one or more first atmospheric agents using a thermodynamic modelling software.

[0082] As an example of a predicted deposit composition, for a high pressure turbine blade, the determined composition of the predicted deposit may be a deposit composition (in wt. %) of: CaO=34.10, MgO=7.76, Al.sub.2O.sub.3=10.91, SiO.sub.2=43.41, FeO=1.15, K.sub.2O=0.26, SO.sub.3=0.03, Na.sub.2O=2.35 at a core dose concentration of 10 mg/m.sup.3.

[0083] At step 208, the method 200 further includes determining a predicted damage to the component based at least on the composition and the amount of the predicted deposit, and a composition of the coating of the component. Referring to FIG. 2, for example, the method 200 may include determining a predicted damage to the component 100 based at least on a composition and an amount of the predicted deposit 110, and a composition of the coating 104 of the component 100.

[0084] As used herein, the term predicted damage refers to an estimated damage caused to the component due to formation of melts from deposits on the component. Such deposits may include the predicted deposit and the pre-existing deposit.

[0085] In some embodiments, the predicted damage is further determined based on the composition and the amount of the pre-existing deposit. Referring to FIG. 2, for example, the predicted damage may be further determined based on the composition and the amount of the pre-existing deposit 112.

[0086] In some embodiments, determining the predicted damage is further based on a thickness of the coating of the component and a composition of the substrate of the component. Referring to FIG. 2, for example, determining the predicted damage may be further based on the thickness 115 of the coating 104 of the component 100 and a composition of the substrate 102 of the component 100. In other words, in some examples, the predicted damage to the component 100 may be determined based on the composition and the amount of the predicted deposit 110, the composition and the amount of the pre-existing deposit 112, the composition of the coating 104, the thickness 115 of the coating 104, and the composition of the substrate 102. In some embodiments, the predicted damage may be further based on a density of the coating 104 and/or a porosity of the coating 104. In some embodiments, the predicted damage may be further based on a thermal conductivity, a tortuosity, and a method of deposition of the coating 104 (e.g., EB-PVD, APS, SPS, and so forth). In some embodiments, the predicted damage may be further based on operating parameters of the gas turbine engine 10 (shown in FIG. 1).

[0087] The predicted damage may be quantified based on the thermochemical and/or thermomechanical properties of the predicted deposit 110 and/or the pre-existing deposit 112. The thermochemical and/or thermomechanical properties may include, for example, a melting profile between the solidus and liquidus temperatures of the deposit and the viscosity of the deposit. This may be determined using empirical data or calculated using a thermodynamic modelling software.

[0088] The predicted damage may be further quantified based on reactivity of a material of the component (e.g., nickel super-alloy, TBC, EBC) with the predicted deposit 110 and/or the pre-existing deposit 112. This may be calculated using, for example, solvation models, and libraries/look-up tables of compositional data of deposits formed on service-return components and thermodynamic data calculated using a thermodynamic modelling software.

[0089] The quantified predicted damage may include a depth and an extent of infiltration of a melt (of the predicted deposit and/or the pre-existing deposit) into the coating. The quantified predicted damage may further include a probability/extent of failure of the coating by, for example, cracking, blistering, spallation, and delamination due to the melt. The quantified predicted damage may further include formation of any corrosion products or new phases from reactions of the melt that has a deleterious effect on the coating and the substrate. The quantified predicted damage may further include reactive solvation/depletion of the coating and the substrate of the component by the melt. The quantified predicted damage may further include a probability/extent of pitting/cracking/corrosion of the substrate due to the melt.

[0090] Thus, the method 200 may be used to predict and quantify the damage to the component 100 that may potentially be caused by the ingestion of the one or more first atmospheric agents during operation of the gas turbine engine.

[0091] At step 210, the method 200 further includes determining one or more locations at which one or more second atmospheric agents are present in air that reduce the predicted damage to the component. That is, the one or more second atmospheric agents are predicted to be ingested by the gas turbine engine during operation at the one or more locations, and the one or more second atmospheric agents reduce the predicted damage to the component.

[0092] Specifically, the one or more second atmospheric agents may, for example, react with the predicted deposit and/or the pre-existing deposit to reduce the predicted damage to the component. More specifically, ingestion of the one or more second atmospheric agents by the gas turbine engine may reduce or prevent formation of melts from the predicted and the pre-existing deposits on the component.

[0093] In some embodiments, the one or more second atmospheric agents react with the predicted deposit to change at least one of a thermochemical property and a thermomechanical property of the predicted deposit so as to reduce the predicted damage to the component. Referring to FIG. 2, for example, the one or more second atmospheric agents may react with the predicted deposit 110 to change at least one of a thermochemical property and a thermomechanical property of the predicted deposit 110 so as to reduce the predicted damage to the component 100.

[0094] In some embodiments, the one or more second atmospheric agents may react with the pre-existing deposit to change at least one of a thermochemical property and a thermomechanical property of the pre-existing deposit so as to reduce the predicted damage to the component. Referring to FIG. 2, for example, the one or more second atmospheric agents may react with the pre-existing deposit 112 to change at least one of a thermochemical property and a thermomechanical property of the pre-existing deposit 112 so as to reduce the predicted damage to the component 100.

[0095] For example, the reaction of the one or more second atmospheric agents with the predicted deposit and/or the pre-existing deposit may raise a melting temperature of the predicted deposit and/or the pre-existing deposit to above an operating temperature of the gas turbine engine. Additionally or alternatively, the reaction of the one or more second atmospheric agents with the predicted deposit and/or the pre-existing deposit may increase a viscosity of the predicted deposit and/or the pre-existing deposit in their molten phase.

[0096] As previously disclosed, the one or more first and one or more second atmospheric agents comprise natural aerosols and gases, such as volcanic ash, volcanic glass, volcanic gas, mineral dust, mineral sand, water, ice, sea salt, anthropogenic pollutant gases. These mineral dusts, mineral sands and volcanic ash may comprise crystalline minerals and amorphous material including glasses derived from geological melts.

[0097] Crystalline minerals which may raise a melting temperature of the predicted deposit and/or the pre-existing deposit and/or increase a viscosity of the predicted deposit and/or the pre-existing deposit in their molten phase include carbonates (e.g., calcite, dolomite), clay group minerals (e.g., smectites), mica group minerals (e.g., muscovite, phlogopite), feldspars (e.g., alkali feldspars such as albite; plagioclase feldspar), sulfates (e.g., anhydrite, gypsum) and silica minerals (e.g., quartz).

[0098] Taking carbonates as an example, the one or more second atmospheric agent may comprise minerals with compositions high in CaO (calcium oxide) and/or MgO (magnesium oxide).

[0099] For example, dolomite contains: CaO=30.41 Wt. %, MgO=21.86 Wt. %, CO.sub.2=47.73 Wt. %.

[0100] For example, calcite contains: CaO=56.03 Wt. %, CO.sub.2=43.97 Wt. %.

[0101] Dolomite and calcite are highly abundant in evaporitic sediments and so are present in significant quantities in the dusts that form from these sediments.

[0102] Other minerals which have compositions high in CaO and/or MgO may also be comprised within the one or more second atmospheric agent. Other suitable oxides within the one or more second atmospheric agent may include Al.sub.2O.sub.3, SiO.sub.2, FeO, Fe.sub.2O.sub.3, K.sub.2O and/or Na.sub.2O.

[0103] Referring to FIG. 4, for example, the method 200 may include determining locations L3, L4, L5 at which one or more second atmospheric agents are present. Specifically, air at the locations L3, L4, L5 may include the one or more second atmospheric agents. In some cases, the locations L3, L4, L5 may be determined within a predefined distance from the first location FL and/or the second location SL.

[0104] At step 212, the method 200 further includes determining a composition, a particle size, and a concentration of the one or more second atmospheric agents in the air at the one or more locations. Referring to FIG. 4, for example, the method 200 may include determining a composition, a particle size, and a concentration of the one or more second atmospheric agents in the air at the locations L3, L4, L5.

[0105] In some embodiments, the one or more second atmospheric agents and the composition, the particle size, and the concentration of the one or more second atmospheric agents in the air are determined via at least one of a meteorological database and a meteorological model.

[0106] For example, the one or more second atmospheric agents and the composition, the particle size, and the concentration of the one or more second atmospheric agents present in the air may be determined based on the meteorological data taken from the World Health Organisation (WHO), the Met Office's Numerical Atmospheric-dispersion Modelling Environment (NAME), Quantitative Volcanic Ash (QVA) models, European Centre for Medium-Range Weather Forecasts (ECMWF), and the like.

[0107] At step 214, the method 200 further includes determining an alternative route for the aircraft based on the composition, the particle size, and the concentration of the one or more second atmospheric agents in the air at the one or more locations. The alternative route includes the one or more locations. Further, the alternative route is different from the predefined route.

[0108] Referring to FIG. 4, for example, the method 200 may include determining an alternative route R1 based on the composition, the particle size, and the concentration of the one or more second atmospheric agents in the air at the location L3. In some examples, the method 200 may include determining an alternative route R2 based on the composition, the particle size, and the concentration of the one or more second atmospheric agents in the air at the locations L4, L5. Further, the alternative route R1 and the alternative route R2 may be determined based on prospective risk factors (e.g., low/high risk of damage to the component if operated on the predefined route RD) and fuel consumption.

[0109] In some examples, a distance of the alternative route R1 may be compared with a distance of the alternative route R2 to select one of the alternative routes R1, R2 for the aircraft 50. For example, if the distance of the alternative route R1 is less than the alternative route R2, the alternative route R1 may be selected for the aircraft 50. In some cases, the method 200 may further include looking up a table including a list of airports that are considered to be in the alternative routes R1, R2. The alternative routes R1, R2 may thus further include one or more airports.

[0110] At step 216, the method 200 further includes operating the gas turbine engine in the alternative route of the aircraft, such that the gas turbine engine is operated at the one or more locations. Referring to FIG. 4, for example, the method 200 may include operating the gas turbine engine 10 in the alternative route R1 of the aircraft 50, such that the gas turbine engine 10 is operated at the location L3. In another example, the method 200 may include operating the gas turbine engine 10 in the alternative route R2 of the aircraft 50, such that the gas turbine engine 10 is operated at the locations L4, L5.

[0111] In some embodiments, the gas turbine engine is operated in the alternative route after a predetermined number of cycles of operation in the predefined route. Referring to FIG. 4, for example, the gas turbine engine 10 may be operated in the alternative route R1 after a predetermined number of cycles of operation in the predefined route RD. As an example, the predetermined number of cycles may be 100 cycles, 200 cycles, 300 cycles, and so forth.

[0112] The predetermined number of cycles may be based on the composition, the particle size, and the concentration of the one or more first atmospheric agents in the predefined route. For example, the predicted deposit may not form in a significant amount before the predetermined number of cycles of operation in the predefined route. Therefore, operating the gas turbine engine in the alternative route after the predetermined number of cycles of operation in the predefined route may optimise the number of times the gas turbine engine is operated in the alternative route to reduce the predicted damage.

[0113] In some embodiments, the method 200 further includes changing one or more operating parameters of the gas turbine engine, such that an operating temperature of the gas turbine engine reduces to below melting temperatures of the predicted deposit and the pre-existing deposit. The one or more operating parameters may include, for example, a thrust rating of the gas turbine engine.

[0114] Referring to FIGS. 1 and 2, for example, the method 200 may include changing one or more operating parameters of the gas turbine engine 10, such that an operating temperature of the gas turbine engine 10 reduces to below melting temperatures of the predicted deposit 110 and the pre-existing deposit 112. The thrust rating of the gas turbine engine 10 may be reduced to reduce a maximum temperature experienced by the component 100 to less than the melting temperature of the predicted deposit 110 and/or the pre-existing deposit 112.

[0115] Consequently, the operating temperature of the gas turbine engine may remain lower than melting temperatures of the predicted deposit 110 and the pre-existing deposit 112. Therefore, the predicted deposit 110 and the pre-existing deposit 112 may not form melts during operation of the gas turbine engine 10, thereby reducing damage to the component 100.

[0116] In an alternative embodiment, the method 200 may include, in place of steps 210-216, changing a time of day that the aircraft takes off from a given location (e.g., an airport) and lands on a given location.

[0117] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.