Patent Description:
A typical aircraft-mounted gas turbine engine includes gas turbine engine components having very fine cooling passages that allow for higher gas temperatures in the combustor and/or the high-pressure or low-pressure turbines. During operation, particularly in environments that contain fine-scale dust, environmental particulate accumulates on engine components and within the cooling passages of the engine. For example, dust (reacted or non-reacted), sand, or similar, can build up on the flow path components and on the impingement cooled surfaces during turbine engine operation. In addition, particulate matter entrained in the air that enters the turbine engine and the cooling passages can contain sulfur-containing species that can corrode the components. Such deposits can lead to reduced cooling effectiveness of the components and/or corrosive reaction with the metals and/or coatings of the engine components. Thus, deposits can lead to premature distress and/or reduced engine life. Additionally, accumulations of environmental contaminants (e.g. dust-reacted and unreacted, sand, etc.) can degrade aerodynamic performance of the high-pressure components and lower fuel efficiency of the engine through changes in airfoil morphology. For example, cleaning the blades and vanes of the compressor may improve the efficiency of compression and result in a lower exit temperature for the compressor. This, in turn, may result in a lower operating temperature of the hot section of the engine, which may increase the operating life of the various components. <CIT> relates to methods and systems of generating flows of detergent through a turbine engine to effectuate cleaning of components thereof according to the preamble of independent claims <NUM> and <NUM>. <CIT> relates to equipment for cleaning jet engines. <CIT> relates to a system for extracting vapour and particulates from a flow of at least an air stream. <CIT> relates to a method and system to clean gas turbines using a mist of cleaning fluid.

Accordingly, an improved method to clean gas turbine engine components would be useful.

In one aspect of the invention defined in appended claim <NUM>, the present disclosure is directed to a method for removing a deposit from at least one component of an assembled, on-wing gas turbine engine. The gas turbine engine includes a core gas turbine engine positioned downstream of a fan section. The core gas turbine engine has an absence of powered rotation during the removal of the deposit. The method includes operably coupling a delivery assembly to an annular inlet of the core gas turbine engine. The delivery assembly is coupled to a control unit and a storage vessel containing a cleaning fluid. The method also includes atomizing a portion of the cleaning fluid with the delivery assembly to develop a cleaning mist. The cleaning mist includes a plurality of atomized droplets. The method includes suspending the atomized droplets of the cleaning mist within an airflow within at least one flow path of the core gas turbine engine. The cleaning mist occupies a cross-sectional area of the at least one flow path to establish a simultaneous cross-sectional contact therein. At least a portion of the atomized droplets remains suspended within the flow path(s) from the annular inlet to an axial position downstream of a high-pressure compressor of the gas turbine engine. Additionally, the includes impacting or precipitating a portion of the cleaning mist onto the component(s) so as to wet at least <NUM>% of an exposed, inlet-facing surface of the component(s). Further, the method includes dissolving at least a portion of the deposit on the component(s).

According to the invention, the atomized droplets may have a median diameter of less than or equal to <NUM> microns and the cleaning mist has a fluid-to-air mass ratio of at least <NUM> and less than or equal to <NUM> kilograms of cleaning fluid to kilograms of air.

In an additional embodiment, a thermal state of the core gas turbine engine may be less than or equal to <NUM>% of an ambient air temperature and the axial position downstream of the compressor may be an axial position downstream of the on-wing gas turbine engine.

In a further embodiment, the method may include establishing an elevated delivery temperature of the cleaning mist which increases the vapor content of the cleaning mist within the flow path(s).

In an embodiment, the method may include supplying a surge portion of the cleaning mist to the core gas turbine engine. The method may also include operably decoupling the delivery assembly from the annular inlet. Further, the method may include establishing a soak period during which the cleaning fluid affects the deposit.

In an additional embodiment, the delivery assembly may include an array of nozzles. Each nozzle of the array of nozzles may be configured to develop atomized droplets having a median diameter of less than or equal to <NUM> microns. The method may also include actuating at least one nozzle of the array of nozzles to establish a cleaning mist volume. The cleaning mist volume may include a concentration of atomized droplets within a specified portion of the flow path(s). The cleaning mist volume may be characterized by a fluid-to-air mass ratio of at least <NUM> and less than or equal to <NUM> kilograms of cleaning fluid to kilograms of air.

In a further embodiment, the method may include obtaining environmental data. The environmental data may include an ambient temperature, an ambient pressure, and an ambient humidity affecting the on-wing gas turbine engine. The method may also include obtaining data indicative of a thermal state of the core gas turbine engine. Based on the environmental data and the data indicative of the thermal state of the core gas turbine engine, the method may include establishing the cleaning mist volume delivered to the annular inlet. Establishing the cleaning mist volume may also include establishing a cleaning mist flow rate within the flow path(s).

In an embodiment, the method may include monitoring an absolute humidity level at a point-of-departure from the on-wing gas turbine engine. The method may also include utilizing the monitored humidity level to determine a percentage of the delivered cleaning mist remaining suspended at the point-of-departure from the on-wing gas turbine engine. Additionally, the method may include adjusting the cleaning mist volume delivered to the annular inlet based on the determined percentage so as to achieve a desired level of wetting of the component(s).

In an additional embodiment, the method may include determining a first volume of cleaning fluid atomized and delivered as the cleaning mist to the annular inlet. The method may also include determining a second volume of cleaning fluid suspended at the point-of-departure from the on-wing gas turbine engine based on the monitored humidity level. Additionally, the method may include computing the portion of the first volume of cleaning fluid precipitated onto the component(s) based on a difference between the first and second volumes. Further, the method may include adjusting the cleaning mist volume delivered to the annular inlet so that the second volume is less than or equal to <NUM>% of the first volume.

In a further embodiment, the delivery assembly may include an array of nozzles. Additionally, operably coupling the delivery assembly to the annular inlet may also include positioning the array of nozzles within the fan section so that an outlet of each nozzle of the array of nozzles is arranged at an axial location between the fan section and the annular inlet of the core gas turbine engine. Additionally, the method may include circumscribing the array of nozzles with at least one blocking element. The blocking element(s) may at least partially occlude an alternative flow path.

In an embodiment, removing the deposit from the component(s) of the on-wing gas turbine engine may be repeated at least once every <NUM> days.

In an additional embodiment, the method may include establishing a cleaning cycle. The cleaning cycle may have a duration of <NUM> minutes or less. The method may also include operably decoupling the delivery assembly from the annular inlet by a conclusion of the cleaning cycle.

In a further embodiment, atomizing a portion of the cleaning fluid may include atomizing less than <NUM> liters of cleaning fluid.

In an additional aspect of the invention defined in appended claim <NUM>, the present disclosure is directed to a system for cleaning deposits from at least one component of an assembled, on-wing gas turbine engine. The on-wing gas turbine engine may include a core gas turbine engine positioned downstream of a fan section. The on-wing gas turbine engine may have an absence of powered rotation during the removal of deposits. The system includes a storage vessel containing a cleaning fluid. The system also includes a delivery assembly operably coupled to the storage vessel and a control unit. The delivery assembly includes at least one nozzle. The nozzle is configured to atomized a portion of the cleaning fluid to develop a cleaning mist. The cleaning mist includes a plurality of atomized droplets. The atomized droplets have a median diameter facilitating suspension of the atomized droplets within the flow path(s) of the core gas turbine engine from an annular inlet of the core gas turbine engine to an axial position downstream of a high-pressure compressor of the core gas turbine engine. The cleaning mist occupies a cross-sectional area of the flow path(s) to establish a simultaneous cross-sectional contact therein. Additionally, the system includes a flow generation assembly. The flow generation assembly is oriented to facilitate a passage of the cleaning mist along the flow path(s) of the core gas turbine engine. The atomized droplets have a median diameter of less than or equal to <NUM> microns and the cleaning mist has a fluid-to-air mass ratio of at least <NUM> and less than or equal to <NUM> kilograms of cleaning fluid to kilograms of air. It should be appreciated that the system may further include any of the features described herein.

As used herein, the terms "first" and "second" may be used interchangeably to distinguish one component(s) from another and are not intended to signify location or importance of the individual component(s)s.

As used herein, the term "vapor" refers to a substance in the gaseous state, as distinguished from the liquid or solid state.

As used herein, the fluid flow is in the direction encountered by the gas turbine engine in flight operations.

As used herein, the phrases "constructed of CMCs" and "comprised of CMCs" shall mean component(s)s substantially constructed of CMCs. More specifically, the CMC component(s)s shall include more CMC material than just a layer or coating of CMC materials. For example, the component(s)s constructed of CMCs may be comprised or constructed substantially or entirely of CMC materials, including greater than about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> percent CMC material.

Certain approaches for treating assembled engines may rely on foam or liquids. However, the physical characteristics of the treating medium may impose limits on the engine surfaces which may be affected. Additionally, certain approaches to cleaning engines on-wing may require the aircraft to be positioned in a maintenance area of an airfield and taken out of service for an undesirable length of time. For example, certain approaches may require that the aircraft be taken out of service for <NUM>-<NUM> hours and may require the disassembly of a portion of the engine, the presence of a crew in a cockpit, and/or an external power source to rotate the engine. As a result of these drawbacks, it may not be practical for these cleaning approaches to be practiced more than <NUM>-<NUM> times per year. The extended intervals between cleanings may result in the engine being operated in a fouled condition for a greater percentage of the time.

One or more of the above-identified issues may be addressed by the presently disclosed methods and systems. In particular, methods and systems are generally provided for cleaning/removing deposits from components of an assembled, on-wing gas turbine engine. The methods of the present disclosure generally provide for introducing a cleaning mist into the annular inlet of the engine. The cleaning mist includes atomized particles of a cleaning fluid which are sized to permit the cleaning mist to remain suspended in a flow path of the core engine at least to a location downstream of a high-pressure compressor. As the cleaning mist flows along the flow path, the atomized particles may encounter various components of the engine. When encountering the various components, the atomized particles impact the component and/or precipitate onto the component thereby wetting the component with the cleaning fluid. By utilizing the cleaning mist, the methods described herein may be accomplished in <NUM> minutes or less without requiring the disassembly or rotation of the engine. Additionally, the utilization of the cleaning mist to wet the components facilitates an efficient cleaning cycle utilizing less than <NUM> liters cleaning fluid.

Referring now to the drawings, <FIG> illustrates a cross-sectional view of one embodiment of an assembled, on-wing gas turbine engine <NUM> that may be utilized with an aircraft in accordance with aspects of the present subject matter, the engine <NUM> is shown having a longitudinal or axial centerline axis <NUM> extending therethrough for reference purposes. In an embodiment, the engine <NUM> may include at least one component <NUM> configured to affect a portion of ambient air entering the engine <NUM>. The component(s) <NUM> may include any of the elements of the engine <NUM> discussed herein. In an embodiment, the component(s) <NUM> may, for example, be formed from CMC, titanium, steel, aluminum, nickel, chromium and/or combinations thereof. Additionally, it should be appreciated that while the engine <NUM> is depicted in <FIG> as a turbofan jet engine, the systems and methods described herein may be employed on any turbomachine including, but not limited to, high-bypass turbofan engines, low-bypass turbofan engines, turbojet engines, turboprop engines, turboshaft engines, propfan engines, and so forth.

In general, the engine <NUM> includes a core gas turbine engine (indicated generally by reference character <NUM>) and a fan section <NUM> positioned upstream thereof. The core engine <NUM> may generally include a substantially tubular outer casing <NUM> that defines an annular inlet <NUM>. The annular inlet <NUM> may define an entrance to at least one flow path <NUM> of the core engine <NUM>.

In an embodiment, the outer casing <NUM> may enclose and support a booster compressor <NUM> for increasing the pressure of the air that enters the core engine <NUM> to a first pressure level. A high-pressure (HP), multi-stage, axial-flow compressor <NUM> may be serially arranged at an axial position downstream of the booster compressor <NUM>. In operation, the HP compressor <NUM> may receive the pressurized air from the booster compressor <NUM> and further increase the pressure of such air.

In an embodiment, a combustor <NUM> may be serially arranged at an axial position downstream of the HP compressor <NUM>. In operation, pressurized air exiting the HP compressor <NUM> may flow to the combustor <NUM> within which fuel may be injected by a fuel system <NUM> into the flow of pressurized air, with the resulting mixture being combusted within the combustor <NUM>.

Referring still to <FIG>, in an embodiment, an HP turbine <NUM> may be serially arranged at an axial position downstream of the combustor <NUM> so that high energy combustion products may be directed from the combustor <NUM> along the flow path(s) <NUM> of the engine <NUM> to the HP turbine <NUM> for driving the HP compressor <NUM> via an HP driveshaft the <NUM>.

In an embodiment, a low-pressure (LP) turbine <NUM> may be serially arranged at an axial position downstream of the HP turbine <NUM>. The LP turbine <NUM> may be configured for driving the booster compressor <NUM> and the fan section <NUM> via an LP driveshaft <NUM>. In an embodiment, the LP driveshaft <NUM> may be generally coaxial with HP driveshaft <NUM>.

As depicted in <FIG>, the flow path(s) <NUM> may communicatively couple the annular inlet <NUM> with a point-of-departure <NUM> from the engine <NUM>. For example, in operation, after driving the HP turbine <NUM> and the LP turbine <NUM>, the combustion products in the flow path(s) <NUM> may be expelled from the core engine <NUM> via the point-of-departure <NUM> configured as an exhaust nozzle to provide propulsive jet thrust.

It should be appreciated that each turbine may generally include one or more turbine stages, with each stage including a turbine nozzle and a downstream turbine rotor. As will be described below, the turbine nozzle may include a plurality of vanes disposed in an annular array about the centerline axis <NUM> of the engine <NUM> for turning or otherwise directing the flow of combustion products through the turbine stage towards a corresponding annular array of rotor blades forming part of the turbine rotor. As is generally understood, the rotor blades may be coupled to a rotor disk of the turbine rotor, which is, in turn, rotationally coupled to the turbine's driveshafts <NUM>, <NUM>.

Additionally, as shown in <FIG>, the fan section <NUM> of the engine <NUM> may generally include a rotatable, axial-flow fan rotor <NUM> surrounded by an annular fan casing <NUM>. In an embodiment, the LP driveshaft <NUM> may be operably coupled to the fan rotor <NUM>. It should be appreciated that the fan casing <NUM> may be supported relative to the core engine <NUM> by a plurality of substantially radially-extending, circumferentially-spaced outlet guide vanes <NUM>. As such, the fan casing <NUM> may enclose the fan rotor <NUM> and its corresponding fan rotor blades <NUM>. Moreover, a downstream section <NUM> of the fan casing <NUM> may extend over an outer portion of the core engine <NUM> to define at least one alternative flow path <NUM> between the fan casing <NUM> and the outer casing <NUM> of the core engine <NUM>. In an embodiment, the alternative flow path(s) <NUM> may provide additional propulsive jet thrust.

As shown in <FIG>, in an embodiment, a system <NUM> may be utilized to clean deposits from the component(s) <NUM> of the assembled, on-wing gas turbine engine <NUM>. The system <NUM> may be employed when the core engine <NUM> is essentially stationary and not being rotated via the application of a power source. The system <NUM> includes a storage vessel <NUM> containing a cleaning fluid <NUM>. The system <NUM> also includes a delivery assembly <NUM> operably coupled to the storage vessel <NUM> and a control unit <NUM>. The delivery assembly <NUM> includes at least one nozzle <NUM> configured to atomize a portion of the cleaning fluid <NUM> in order to develop a cleaning mist <NUM>. The cleaning mist <NUM> includes a plurality of atomized droplets. The atomized droplets have a median diameter, and thus mass, which facilitates suspension of the atomized droplets within the flow path(s) <NUM> of the core engine <NUM>. According to the invention defined in claim <NUM>, a portion of the atomized droplets of the cleaning mist <NUM> may be suspended within an airflow <NUM> within the flow path(s) <NUM> from the annular inlet <NUM> to an axial position (A) downstream of the HP compressor <NUM>. The cleaning mist <NUM> occupies a cross-sectional area of the flow path(s) <NUM> to establish a simultaneous cross-sectional contact therein. In other words, in an embodiment, the cleaning mist <NUM> may essentially fill the flow path(s) <NUM> at a given axial location without requiring that the engine <NUM> be rotated. The system <NUM> also includes a flow generation assembly <NUM> which is oriented to facilitate a passage of the cleaning mist <NUM> along the flow path(s) <NUM> of the core engine <NUM>.

In an embodiment, the cleaning fluid <NUM> may include any suitable composition now known or later developed in the art. For example, in an embodiment, the cleaning fluid <NUM> may include a biodegradable citric and/or glycolic-acid composition including both ionic and non-ionic surfactants and/or corrosion inhibition properties. Accordingly, the cleaning fluid <NUM> may be compatible with all coatings and components <NUM> internal and external to the engine <NUM> and suitable for on-wing application. The cleaning fluid <NUM> may be utilized without requiring a rinse step prior to firing the engine <NUM> following the cleaning. The cleaning fluid <NUM> may demonstrate no pitting corrosion or intergranular attack to engine parent metals or coding systems. Accordingly, the cleaning fluid <NUM> may be a water-based cleaning fluid. For example, in an embodiment, the cleaning fluid <NUM> may be a water-detergent combination. In a further embodiment, the cleaning fluid <NUM> may be water without a detergent. Additionally, the water may be treated to remove potential contaminants, such as by distillation and/or deionization.

The cleaning fluid <NUM> may be configured to affect the component(s) <NUM> by wetting the component(s) <NUM>. The wetting of the component(s) <NUM> may, in an embodiment, include the formation of a liquid film that substantially covers an exposed surface of the component(s) <NUM>. For example, the system <NUM> may be configured to form a liquid film over greater than <NUM>% (e.g., at least <NUM>%) of the exposed, inlet-facing surface of the component(s) <NUM> (e.g., blades and vanes of the HP compressor <NUM>).

It should be appreciated that the wetting of the component(s) <NUM> may permit the cleaning fluid <NUM> to dissolve/de-bond a portion of the deposit on the component(s) <NUM>. The dissolution of a portion of the deposit may weaken a bond between the deposited contamination and the surface of the component(s) <NUM>. In such an embodiment, the weakened bond may permit an additional portion of the deposited contamination to be removed by thermodynamic and/or mechanical forces during a startup of the engine <NUM>.

In an embodiment, the cleaning fluid <NUM> may be configured to be delivered to the engine <NUM> at a constant rate. In an additional embodiment, the cleaning fluid <NUM> may be delivered to the engine <NUM> at a variable rate. For example, in an embodiment, a first portion of the cleaning fluid <NUM> may be delivered at the initiation of the cleaning cycle so as to rapidly wet the component(s) <NUM>. The amount of cleaning fluid <NUM> delivered to the engine may then be reduced and the wetted component(s) <NUM> may be permitted to soak. During the soak, a desired level of wetness may be maintained via a second portion of the cleaning fluid <NUM>, which may be less than the first portion of the cleaning fluid <NUM>. Following at least one soak, a third portion of the cleaning fluid <NUM> may be introduced so as to increase the wetness of the component(s) <NUM>. As is more fully described below, the third portion of the cleaning fluid <NUM> may be considered a surge portion.

According to the invention, atomizing a portion of the cleaning fluid <NUM> with the delivery assembly <NUM> develops the cleaning mist <NUM>. The cleaning mist <NUM> includes a plurality of atomized droplets of the cleaning fluid <NUM> suspended in a volume of gas, such as a volume of atmospheric air. For example, in an embodiment wherein the cleaning fluid <NUM> is a water-based cleaning fluid, the development of the cleaning mist <NUM> may result in a supersaturated vapor component of the cleaning mist <NUM> having a water content in excess of that naturally occurring under prevailing ambient conditions. In other words, the atomization of the water of the cleaning fluid <NUM> may result in a portion of the atomized droplets evaporating in the air to which the atomized droplets of the cleaning fluid <NUM> are introduced, thereby raising the fluid content of the resultant vapor component of the cleaning mist <NUM>. The remaining portion of the atomized cleaning fluid <NUM> comprising the cleaning mist <NUM> may remain as water and/or water-detergent droplets which are entrained in a flow of the vapor component. According to the invention, the cleaning mist <NUM> has a fluid-to-air mass ratio of at least <NUM> and less than or equal to <NUM> kilograms of cleaning fluid to kilograms of air. For example, in an embodiment, the fluid-to-air mass ratio may be at least <NUM> and less than <NUM>.

It should be appreciated that the effectiveness of the cleaning mist <NUM> may be increased by heating the cleaning fluid <NUM>, heating the portion of air into which the atomized droplets of the cleaning fluid <NUM> are introduced, and/or increasing the delivery pressure of the cleaning fluid <NUM> prior to delivery of the cleaning mist <NUM> to the annular inlet <NUM>. Such techniques may increase the fluid content of the cleaning mist <NUM> thereby facilitating the wetting of the component(s) <NUM>. For example, for a water-based cleaning fluid <NUM>, the cleaning fluid <NUM> may be expelled by the nozzle <NUM> at a temperature from <NUM> to <NUM> and/or a pressure from <NUM> kPa to <NUM>,<NUM> kPa. In such an embodiment, the engine <NUM> to be cleaned may be at a standard atmosphere of <NUM> at <NUM> kPa. Upon delivery to the annular inlet, the cleaning fluid <NUM> may encounter lower pressure and temperature conditions than the delivery pressure and temperature, such that the treatment compound vaporizes (if not already a vapor). Because the water-based treatment compound has a delivery pressure (partial pressure) from <NUM> kPa to <NUM>,<NUM> kPa, and the saturation pressure of a water-based compound at <NUM> is about <NUM> kPa, the resultant vapor may be supersaturated. It should be appreciated that the term "supersaturated," as used herein, refers to a vapor of a compound that has a higher partial pressure than the vapor pressure of the compound.

In order to increase the temperature of the cleaning fluid <NUM> and/or the portion of air into which it is introduced, the system <NUM> may include at least one heating element <NUM>. The heating element(s) <NUM> may be positioned in thermal contact with the cleaning mist <NUM> so as to establish an elevated delivery temperature of the cleaning mist <NUM> relative to the ambient temperature which increases the vapor content of the cleaning mist <NUM>. For example, in an embodiment, the heating element(s) <NUM> may be positioned in thermal contact with the cleaning fluid <NUM> contained within the storage vessel <NUM>. In an additional embodiment, the heating element(s) <NUM> may be positioned in thermal contact with an airflow <NUM> generated by the flow generation assembly <NUM>. Positioning the heating element(s) <NUM> in thermal contact with the airflow <NUM> may increase the temperature of the portion of air into which the atomized droplets of the cleaning fluid <NUM> are introduced.

Referring still to <FIG>, in an embodiment, the atomized droplets of the cleaning mist <NUM> have a median diameter, and therefore mass, which facilitates the atomized droplets remaining suspended in a portion of air within the flow path(s) <NUM>. At least a portion of the atomized droplets is entrained in the airflow <NUM> through the flow path(s) <NUM> from the annular inlet <NUM> to the axial position (A) downstream of the HP compressor <NUM>. It should be appreciated that at various points along the flow path(s) <NUM>, the airflow <NUM> may experience a deceleration, such as due to a directional change of the airflow <NUM>. As a result of the deceleration, the airflow <NUM> may lack the necessary energy to retain atomized droplets above a specified mass, as defined by the median diameter. When the energy level of the airflow <NUM> drops below a given threshold for atomized particles of a given size, the atomized particles may depart the airflow <NUM> and impact/precipitate within the core engine <NUM>. Further, for atomized particles a ball of a given size, the inertial energy of the particles may result in the atomized particles departing the airflow <NUM>. Accordingly, in order for at least a portion of the atomized droplets to remain suspended within the flow path(s) <NUM> from the annular inlet <NUM> to the axial position (A), according to the invention, the atomized droplets have a median diameter of less than or equal to <NUM> microns.

In an additional embodiment, the supportability of the cleaning mist <NUM> within the flow path(s) <NUM> may be enhanced by the formation of a cleaning mist <NUM> having atomized droplets with a median diameter greater than or equal to <NUM> microns and less than or equal to <NUM> microns. In other words, in an embodiment wherein the water and/or water-detergent droplets have a median diameter in a range between <NUM> and <NUM> microns inclusive, the droplets may be entrained in the flow of the vapor component which through the core engine <NUM>. For example, in an embodiment, a thermal state of the core engine <NUM> may be less than or equal to <NUM>% of an ambient air temperature in degrees Celsius. In such an embodiment, the median diameter of the atomized droplets may facilitate a portion of the cleaning mist <NUM> remaining suspended within the airflow <NUM> to an axial position downstream (B) of the on-wing gas turbine engine <NUM>.

In order to develop droplets having the required median diameter, the delivery assembly <NUM> atomizes a portion of the cleaning fluid <NUM>. The delivery assembly <NUM> utilizes the nozzle <NUM> to develop the cleaning mist <NUM> having atomized droplets of the desired median diameter. The nozzle <NUM> may utilize at least one orifice and/or the application of ultrasonic energy via an ultrasonic nozzle to atomize the cleaning fluid <NUM>. For example, the cleaning fluid <NUM> may be drawn through the orifice(s) via a pressure differential across the orifice(s). Alternatively, the cleaning fluid <NUM> may be driven through the orifice(s) by the development of a higher pressure within the storage vessel <NUM> than at the orifice(s). The higher pressure may be developed via a pump, a compressed air source <NUM>, and/or heating. In at least one embodiment, the compressed air source <NUM> may also be configured as the flow generation assembly <NUM> to facilitate the passage of the cleaning mist <NUM> along the flow path(s) <NUM>.

In an additional embodiment, the nozzle <NUM> may be configured as an ultrasonic transducer. In such an embodiment, the nozzle <NUM> may be inserted into a portion of the cleaning fluid <NUM> so as to atomize a portion of the cleaning fluid <NUM>. The resultant atomized portion may be drawn from the cleaning fluid <NUM> by the flow generation assembly <NUM> for delivery to the annular inlet <NUM>.

As depicted in <FIG>, the nozzle <NUM> is positioned upstream of the fan section <NUM> and operably coupled to the annular inlet <NUM> of the core engine <NUM>. In an additional embodiment, the nozzle <NUM> may be one of an array of nozzles <NUM>. For example, the array of nozzles <NUM> may include four or more nozzles <NUM>. As depicted in <FIG>, the array of nozzles <NUM> may be arranged to interface with the fan section <NUM> so as to position an outlet <NUM> of each nozzle <NUM> at an axial location between the fan section <NUM> and the annular inlet <NUM>. In such an embodiment, the number of nozzles <NUM> of the array of nozzles <NUM> may correspond to the number of spaces between the fan blades <NUM> such that at least one nozzle <NUM> is inserted between each pair of fan blades <NUM>. In an embodiment, the nozzles <NUM> may be operably coupled to the annular inlet <NUM> without necessitating contact with the engine <NUM>.

In an embodiment wherein the delivery assembly <NUM> includes the array of nozzles <NUM>, modifying the number nozzles <NUM> employed to atomize the portion of the cleaning fluid <NUM> may affect the concentration of atomized droplets within a specified portion <NUM> of the flow path(s) <NUM>. As such, modifying the number of nozzles <NUM> may establish a cleaning mist volume. For example, in an embodiment wherein the entire array of nozzles <NUM> is activated, the concentration of atomized droplets may be greater than in an embodiment wherein the majority of the array of nozzles <NUM> are idle.

Referring now particularly to <FIG>, in an embodiment, the delivery assembly <NUM> may include a duct portion <NUM> communicatively coupled between the core engine <NUM> and the storage vessel <NUM>. In such an embodiment, the atomization of the cleaning fluid <NUM> may occur in, or adjacent to, the storage vessel <NUM>. The atomized droplets may enter the duct portion <NUM> of the delivery assembly <NUM> and be delivered to the annular inlet <NUM> by the flow generating assembly <NUM>. In an embodiment, the flow generating assembly <NUM> may be incorporated into the duct portion <NUM>. Additionally, in an embodiment, duct portion <NUM> may incorporate the heating element(s) <NUM>.

Referring again to <FIG>, according to the invention, the system <NUM> includes the flow generation assembly <NUM>. The flow generation assembly <NUM> facilitates the passage of the cleaning mist <NUM> along the flow of path <NUM> by developing the airflow <NUM>. In an embodiment, the flow generation assembly <NUM> may be configured to drive or draw a portion of atmospheric air so as to generate the airflow <NUM>. In such an embodiment, the flow generation assembly <NUM> may, for example, be configured as a fan. Accordingly the flow generation assembly may be positioned upstream of the annular inlet <NUM> when configured to accelerate or drive the airflow <NUM> and may be positioned downstream of the engine <NUM> when configured to draw the cleaning mist <NUM> through the flow path(s) <NUM>.

In an embodiment, the flow generation assembly <NUM> may be configured to establish a pressure differential between the annular inlet <NUM> and the point-of-departure <NUM>. For example, in an embodiment, the flow generation assembly <NUM> may be configured as the compressed air source <NUM>. In such an embodiment, the compressed air may not only drive the cleaning fluid <NUM> through the nozzle <NUM>, but the venting of the compressed air through the nozzle <NUM> may create a region of increased pressure in fluid communication with the annular inlet <NUM>. The region of increased pressure may drive the cleaning mist <NUM> through the flow path(s) <NUM>. In a further embodiment, a high-pressure region may be established adjacent to the annular inlet <NUM> via the heating of a portion of atmospheric air adjacent to the annular inlet <NUM>. In yet a further embodiment, the flow generation assembly <NUM> may be positioned downstream of the engine <NUM> and configured to establish a low-pressure region adjacent to the point-of-departure <NUM>.

Referring still to <FIG>, in an embodiment, the flow generation assembly <NUM> of the system <NUM> may be configured as a heat source positioned downstream of the point-of-departure <NUM>. In such an embodiment, the flow generation assembly <NUM> may heat the portion of atmospheric air adjacent to the point-of-departure <NUM>. This heating of the atmospheric air may establish the airflow <NUM> as a convection current through the core engine <NUM>. The cleaning mist <NUM> may be drawn through the flow path(s) <NUM> via the convection current.

Referring again to <FIG>, according to the invention, the system <NUM> includes a control unit <NUM>. The control unit <NUM> may, in an embodiment, include a plurality of controls configured to permit an operator to employ the system <NUM> to remove a deposit from the component(s) <NUM> of the assembled, on-wing gas turbine engine <NUM>. In at least one embodiment, the control unit may include various readouts configured to provide the operator with information concerning the cleaning of the engine <NUM> and various manual controls configured to provide the operator with the necessary degree of control over the methods described herein to remove deposits from the component(s) <NUM>. In an additional embodiment, the control unit <NUM> may also include a controller <NUM>. The controller <NUM> may also be configured to implement the methods discussed herein to remove the deposit from the component(s) <NUM> of the engine <NUM>. It should be appreciated that the controller <NUM> may be employed in combination with various manual controls and displays to facilitate an operator's control of the methods described herein.

In an embodiment, removing the deposit from the component(s) <NUM> may include the operator/controller <NUM> obtaining environmental data indicative of the environmental conditions affecting the on-wing gas turbine engine. For example, the environmental data may include an ambient temperature, an ambient pressure, and an ambient humidity affecting the <NUM>. In an embodiment, the environmental data may also include data indicative of the type of suspended atmospheric particulate (e.g. dust-reacted and unreacted, sand, etc.), an atmospheric particulate concentration, and/or an atmospheric particulate size for an operating environment of the engine <NUM>. In other words, the environmental data may include data on the type and severity of contaminants encountered during the engine's operations. It should be appreciated that the information concerning the encountered particulates may be utilized by the operator/controller <NUM> to determine a cleaning fluid composition, cleaning operation duration and/or cleaning operation frequency. It should further be appreciated that the environmental data may be obtained from any suitable source, such as a plurality of sensors, an external provider, and/or a lookup table.

The operator/controller <NUM> may also obtain data indicative of the thermal state of the core engine <NUM>. The thermal state may indicate a difference between the temperature of components within the core engine <NUM> and the ambient temperature. The data indicative of the thermal state may be obtained via at least one sensor and/or via a lookup table. For example, the thermal state may be determined relative to an elapsed time since engine shutdown under ambient atmospheric conditions. Based on the environmental data and the data indicative of the thermal state, the operator/controller <NUM> may establish the cleaning mist volume delivered to the annular inlet <NUM>. For example, establishing the cleaning mist volume may include actuating a nozzle <NUM> to establish a concentration of atomized droplets within a specified portion <NUM> of the flow path(s) <NUM> at a specified time interval. Additionally, establishing the cleaning mist volume may also include establishing a cleaning mist flow rate within the flow path(s) <NUM>. Establishing the cleaning mist flow rate may include establishing/modifying the velocity of the airflow <NUM>. It should be appreciated that the velocity of the airflow <NUM> in conjunction with the number of nozzles <NUM> actuated may affect the resultant density of the cleaning mist <NUM> within the flow path(s) <NUM>.

Referring still to <FIG>, in an embodiment, the system <NUM> may also include in electronic sensor <NUM> (e.g., a humidity sensor, a lidar unit, an anemometer, and/or any other suitable sensor for detecting water/ water vapor). The electronic sensor <NUM> may be communicatively coupled to the control unit <NUM> and may be positioned at the point-of-departure <NUM> from the assembled, on-wing, gas turbine engine <NUM>. The electronic sensor <NUM> may monitor an absolute humidity level and/or quantity of liquid water droplets at the point-of-departure <NUM>. The absolute humidity level/ water droplet quantity may be utilized by the operator/controller <NUM> to determine a percentage of the delivered cleaning mist <NUM> remaining suspended at the point-of-departure <NUM> from the engine <NUM>. For example, the absolute humidity level at the point-of-departure <NUM> may, when corrected for the ambient temperature, be indicative of the fluid content of the airflow <NUM> at the point-of-departure <NUM>. The fluid content may, in turn, be indicative of a percentage of cleaning mist <NUM> introduced to the annular inlet <NUM> which remains suspended at the point-of-departure <NUM>.

Utilizing the determined percentage of the cleaning mist <NUM> remaining suspended at the point-of-departure <NUM>, the operator/controller <NUM> may, in an embodiment, adjust the cleaning mist volume delivered to the annular inlet <NUM> so as to achieve a desired level of wetting of the component(s) <NUM>. For example, in an embodiment wherein the thermal state of the engine <NUM> is relatively high when the system <NUM> is activated, a significant percentage of the cleaning mist <NUM> may be converted to vapor in cooling the core engine <NUM>. In such an embodiment, the absolute humidity level at the point-of-departure <NUM> may be relatively close to the ambient humidity level and may indicate a need to increase the cleaning mist volume to achieve the desired level of wetting of the component(s) <NUM>. In a further embodiment, the absolute humidity level at the point-of-departure <NUM> may be significantly higher than the ambient humidity level, thus indicating an excessive amount of cleaning mist <NUM> remains suspended at the point-of-departure <NUM>. In such an embodiment, the operator/controller <NUM> may reduce the cleaning mist volume and/or the velocity of airflow <NUM> so as to improve the efficiency of the system <NUM>. Accordingly, in an embodiment, a cleaning cycle of the engine <NUM> may consume less than <NUM> liters of cleaning fluid <NUM>.

In an embodiment, such as particularly depicted in <FIG> and <FIG>, the system <NUM> may be configured to determine a first volume of cleaning fluid <NUM> atomized and delivered as the cleaning mist <NUM> to the annular inlet. The first volume may, for example, be determined via the monitoring of a dispersal rate of the cleaning fluid <NUM> from the storage vessel <NUM>. In an embodiment, the system <NUM> may also be configured to determine a second volume <NUM> of cleaning fluid <NUM> suspended at the point-of-departure <NUM> based on the retained total water level as may be indicated by the monitored absolute humidity level. Computing the difference between the first and second volumes may indicate the portion of the first volume of the cleaning fluid <NUM> precipitated/impacted onto the component(s) <NUM>.

In an embodiment, the operator/controller <NUM> may adjust the cleaning mist volume delivered to the annular inlet <NUM> so that the second volume is less than or equal to <NUM>% of the first volume. In other words, the system <NUM> may, in an embodiment, be configured to deliver the cleaning mist <NUM> at a cleaning mist volume and flowrate at which <NUM>% or more of the cleaning mist <NUM> is deposited within the core engine <NUM>. This may, for example, be desirable in an embodiment wherein the engine <NUM> is in a cold, thermally stable condition. However, for a hot engine <NUM>, excess cleaning fluid <NUM> may be introduced to the engine <NUM> so as to accelerate the cooling and wetting of the surfaces of the component(s) <NUM>. Accordingly, the second volume may exceed <NUM>% of the first volume. It should be appreciated that ensuring that no more than <NUM>% of the cleaning mist <NUM> passes completely through the core engine <NUM> once the core engine <NUM> is cooled may ensure that the system <NUM> is operating in an efficient manner. For example, the efficient manner may be defined by the execution of a cleaning cycle within <NUM> minutes which consumes less than <NUM> liters of cleaning fluid <NUM>.

Referring again to <FIG>, in an embodiment, the system <NUM> may include at least one blocking element <NUM> circumscribing the annular inlet <NUM>. Additionally, in an embodiment, the blocking element(s) <NUM> may circumscribe the array of nozzles <NUM>. The blocking element(s) <NUM> may at least partially occlude the alternative flow path(s) <NUM>. It should be appreciated that occluding the alternative flow path(s) <NUM>, may increase the efficiency of the system <NUM> by reducing or eliminating the portion of the cleaning mist <NUM> which may bypass the flow path(s) <NUM>.

Referring now to <FIG>, in an embodiment, the system <NUM> may be configured for employment on the engine <NUM> while the aircraft <NUM> is parked at a gate <NUM> of an airport <NUM>. Accordingly, the engine <NUM> may be cleaned utilizing the system <NUM> following a landing <NUM> or prior to a takeoff <NUM> without requiring that the aircraft <NUM> be moved to a maintenance area of the airport <NUM>. It should be appreciated that performing the cleaning operations described herein while the aircraft <NUM> is located at the gate <NUM> may reduce or eliminate the amount of time the aircraft <NUM> is removed from service for engine cleaning operations.

In an embodiment, the system <NUM> may be configured to execute a cleaning cycle which has a duration of <NUM> minutes or less and a consumption of less than <NUM> liters. For example, the system <NUM> may be employed to dissolve a portion of the deposits on the component(s) <NUM> within <NUM> minutes of the cycle initiation with a consumption of less than <NUM> liters.

In an embodiment, following the conclusion of the cleaning cycle, the delivery assembly <NUM> may be operably decoupled from the annular inlet <NUM>. However, as the cleaning cycle disclosed herein does not require a rinse cycle, the component(s) <NUM> may remain in a wetted condition following the operable decoupling of the delivery assembly <NUM>.

In an embodiment, the absence of a requirement to rinse the engine may be leveraged by supplying a surge portion of the cleaning mist <NUM> to the core engine <NUM> prior to operably decoupling the delivery assembly <NUM>. In such an embodiment, a soak period may be established following the operable decoupling of the delivery assembly <NUM> during which the cleaning fluid <NUM> continues affecting the deposits on the component(s) <NUM>. Accordingly, the surge portion may increase the wetness of the component(s) <NUM>, thereby increasing the effectiveness of the soak period.

The ability to execute a cleaning cycle within <NUM> minutes or less while the aircraft <NUM> is parked at the gate <NUM> may facilitate an increased cleaning frequency relative to current engine cleaning approaches. As such, in an embodiment, the removing of the deposit from the component(s) <NUM> may be repeated at least once every <NUM> days and/or engine cycles. For example, in an embodiment, the system <NUM> may be employed at least once every <NUM> days to remove deposits from the component(s) <NUM>. It should be appreciated that an engine cycle may correspond to a <NUM>-hour period, a takeoff/landing sequence, and/or a specified quantity of engine operating hours.

In an embodiment, the data on the type and severity of contaminants encountered during the engine's operations may be utilized to modify the cleaning interval. For example, the type and/or severity of the contaminants encountered during the engine's operations may be high and may indicate that a reduced cleaning interval is be warranted. Such particulate conditions may, for example, be encountered when operating the engine <NUM> in dusty/desert environments and may justify removing the deposits from the component(s) <NUM> with the system <NUM> on a nightly basis.

It should be appreciated that frequent cleanings may preserve the efficiency and lifespan of the engine <NUM>. It should also be appreciated that the more frequent cleanings may, individually, remove a smaller percentage of the deposits on the component(s) <NUM> relative to traditional water/foam washes. However, the effects of frequent cleanings may accumulate such that the combined effect of the frequent cleanings is cumulatively greater than any single water/foam wash. As a result, the shortened intervals between cleanings may result in the engine being operated in a less-fouled condition for a greater percentage of the time then is achievable under traditional approaches.

Referring now to <FIG>, a flow diagram of one embodiment of a method <NUM> removing a deposit from at least one component of an assembled, on-wing gas turbine engine is illustrated. The method <NUM> may be implemented using, for instance, the system <NUM> discussed above with references to <FIG>. <FIG> depicts steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that various steps of the method <NUM>, or any of the methods disclosed herein, may be adapted, modified, rearranged, performed simultaneously, or modified in various ways without deviating from the scope of the present disclosure.

As shown at (<NUM>), the method <NUM> includes operably coupling a delivery assembly to an annular inlet of the core gas turbine engine. The delivery assembly being coupled to a control unit and a storage vessel containing a cleaning fluid. As shown at (<NUM>), the method <NUM> includes atomizing a portion of the cleaning fluid with the delivery assembly to develop a cleaning mist. The cleaning mist includes a plurality of atomized droplets. Additionally, as shown at (<NUM>), the method <NUM> includes suspending the atomized droplets of the cleaning mist within an airflow within at least one flow path of the core gas turbine engine. The cleaning mist occupies a cross-sectional area of the at least one flow path to establish a simultaneous cross-sectional contact therein. At least a portion of the atomized droplets remain suspended within the at least one flow path from the annular inlet to an axial position downstream of a compressor of the gas turbine engine. As shown at (<NUM>), the method <NUM> includes impacting or precipitating a portion of the cleaning mist onto the at least one component so as to wet at least <NUM>% of an exposed surface of the at least one component. The method <NUM>, at (<NUM>), further includes dissolving at least a portion of the deposit on the at least one component.

<FIG> provides a block diagram of an exemplary controller <NUM> that may be used to implement the methods and systems described herein according to exemplary embodiments of the present disclosure. Though described below as a computing system, it should be appreciated that in some embodiments, the controller may be an analog system or an electrical system that does not include a computing device. As shown, the computing system <NUM> may include one or more computing device(s) <NUM>. The one or more computing device(s) <NUM> may include one or more processor(s) <NUM> and one or more memory device(s) <NUM>. The one or more processor(s) <NUM> may include any suitable processing device, such as a microprocessor, microcontroller, integrated circuit, logic device, or other suitable processing device. The one or more memory device(s) <NUM> may include one or more computer-readable media, including, but not limited to, non-transitory computer-readable media, RAM, ROM, hard drives, flash drives, or other memory devices.

The one or more memory device(s) <NUM> may store information accessible by the one or more processor(s) <NUM>, including computer-readable instructions <NUM> that may be executed by the one or more processor(s) <NUM>. The instructions <NUM> may be any set of instructions that when executed by the one or more processor(s) <NUM>, cause the one or more processor(s) <NUM> to perform operations. The instructions <NUM> may be software written in any suitable programming language or may be implemented in hardware. In some embodiments, the instructions <NUM> may be executed by the one or more processor(s) <NUM> to cause the one or more processor(s) <NUM> to perform operations, such as implementing one or more of the processes mentioned above.

The memory device(s) <NUM> may further store data <NUM> that may be accessed by the processor(s) <NUM>. For example, the data <NUM> may include a third instance of shared data for a gas turbine engine, as described herein. The data <NUM> may include one or more table(s), function(s), algorithm(s), model(s), equation(s), etc. according to example embodiments of the present disclosure.

The one or more computing device(s) <NUM> may also include a communication interface <NUM> used to communicate, for example, with the other component(s)s of system. The communication interface <NUM> may include any suitable component(s)s for interfacing with one or more network(s), including for example, transmitters, receivers, ports, controllers, antennas, or other suitable component(s)s.

One of ordinary skill in the art will recognize that the inherent flexibility of computer-based systems allows for a great variety of possible configurations, combinations, and divisions of tasks and functionality between and among component(s)s. For instance, processes discussed herein may be implemented using a single computing device or multiple computing devices working in combination. Databases, memory, instructions, and applications may be implemented on a single system or distributed across multiple systems. Distributed component(s)s may operate sequentially or in parallel.

Claim 1:
A method for removing a deposit from at least one component (<NUM>) of an assembled, on-wing aircraft gas turbine engine, the gas turbine engine comprising a core gas turbine engine (<NUM>) positioned downstream of a fan section (<NUM>), the core gas turbine engine (<NUM>) having an absence of powered rotation during the removal of the deposit, the method comprising:
operably coupling a delivery assembly (<NUM>) to an annular inlet (<NUM>) of the core gas turbine engine (<NUM>), the delivery assembly (<NUM>) being coupled to a control unit (<NUM>) and a storage vessel (<NUM>) containing a cleaning fluid (<NUM>), wherein the delivery assembly (<NUM>) is configured to develop atomized droplets having a median diameter of less than or equal to <NUM> microns;
atomizing a portion of the cleaning fluid (<NUM>) with the delivery assembly (<NUM>) to develop a cleaning mist (<NUM>), the cleaning mist (<NUM>) comprising a plurality of atomized droplets;
suspending the atomized droplets of the cleaning mist (<NUM>) within an airflow (<NUM>) within at least one flow path (<NUM>) of the core gas turbine engine (<NUM>), wherein the cleaning mist (<NUM>) occupies a cross-sectional area of the at least one flow path (<NUM>) to establish a simultaneous cross-sectional contact therein, wherein at least a portion of the atomized droplets remains suspended within the at least one flow path (<NUM>) from the annular inlet (<NUM>) to an axial position downstream of a high-pressure compressor (<NUM>) of the core gas turbine engine (<NUM>);
dissolving at least a portion of the deposit on the at least one component (<NUM>),
the method characterized by
impacting or precipitating a portion of the cleaning mist (<NUM>) onto the at least one component (<NUM>) so as to wet at least <NUM>% of an exposed, inlet-facing surface of the at least one component (<NUM>);
and
in that the atomized droplets have a median diameter of less than or equal to <NUM> microns and the cleaning mist (<NUM>) has a fluid-to-air mass ratio of at least <NUM> and less than or equal to <NUM> kilograms of cleaning fluid (<NUM>) to kilograms of air.