Patent ID: 12228041

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

In general, the present subject matter is directed to a system and method for cleaning a gas turbine engine designed for use within an aircraft. In several embodiments, the disclosed system may include a wash stand having a plurality of fluid injection nozzles configured to inject a high volume of cleaning fluid through the engine fan and into the booster compressor for subsequent delivery to the high pressure compressor of the gas turbine engine. Specifically, the wash stand may be initially positioned adjacent to the front or forward end of the engine, such as by rolling or moving the wash stand to the location of the aircraft or by moving the aircraft to the location of the wash stand. Thereafter, with the engine running, a significant volume of cleaning fluid (e.g., water or any other water-based liquid) may be injected through the fan in a manner that allows the cleaning fluid to be directed into the compressor inlet. The high-volume flow of cleaning fluid may then be directed through the booster compressor and/or the high pressure compressor as the engine is being operated to allow the cleaning fluid to clean the various internal components disposed along the engine's working fluid flow path.

In several embodiments, the orientation of the various nozzles of the wash stand relative to the gas turbine engine may be selected so as to allow the cleaning fluid to be injected past the engine's rotating fan blades and into the compressor inlet. Specifically, as will be described below, the nozzles may be angled relative to the engine centerline such that the cleaning fluid is expelled from the nozzles along a flow path that extends radially inwardly from the nozzle outlets. In addition, the nozzles may have a circumferential or tangential orientation relative to the engine centerline such that each nozzle is configured to expel fluid at a positive tangential angle (as defined based on the rotational direction of the fan blades). As such, as the fan blades rotate with operation of the gas turbine engine, the cleaning fluid expelled from the nozzles may be directed along a positive tangential trajectory that allows the cleaning fluid to flow between the rotating fan blades and into the compressor inlet.

It should be appreciated that the disclosed system and related method may provide numerous advantages for cleaning the interior of a gas turbine engine. For example, given the ability to provide a high-volume, targeted flow of cleaning fluid into the engine core, a greater cleansing effect may be provided for the interior components of the gas turbine engine, such as the airfoils of the high pressure compressor. In addition, given that the cleaning operation is performed while the engine is running, the cleaning fluid directed into the compressor inlet will be heated and pressurized, thereby increasing the likelihood that any material build-up on the interior components of the gas turbine (particularly the aft airfoils of the high pressure compressor) is removed and washed out of the system.

Referring now to the drawings,FIG.1illustrates a cross-sectional view of one embodiment of a gas turbine engine10that may be utilized within an aircraft in accordance with aspects of the present subject matter, with the engine10being shown having a longitudinal or axial centerline axis12extending therethrough for reference purposes. In general, the engine10may include a core gas turbine engine (indicated generally by reference character14) and a fan section16positioned upstream thereof. The core engine14may generally include a substantially tubular outer casing18that defines an annular compressor inlet20. In addition, the outer casing18may further enclose and support a booster compressor22for increasing the pressure of the air that enters the core engine14via the compressor inlet20to a first pressure level. A high pressure, multi-stage, axial-flow compressor24may then receive the pressurized air from the booster compressor22and further increase the pressure of such air. The pressurized air exiting the high-pressure compressor24may then flow to a combustor26within which fuel is injected into the flow of pressurized air, with the resulting mixture being combusted within the combustor26. The high energy combustion products are directed from the combustor26along the hot gas path of the engine10to a first (high pressure) turbine28for driving the high pressure compressor24via a first (high pressure) drive shaft30and then to a second (low pressure) turbine32for driving the booster compressor22and fan section16via a second (low pressure) drive shaft34that is generally coaxial with first drive shaft30. After driving each of turbines28and32, the combustion products may be expelled from the core engine14via an exhaust nozzle36to provide propulsive jet thrust.

Additionally, as shown inFIG.1, the fan section16of the engine10may generally include a rotatable, axial-flow fan rotor assembly38that is configured to be surrounded by an annular fan casing40. It should be appreciated by those of ordinary skill in the art that the fan casing40may be configured to be supported relative to the core engine14by a plurality of substantially radially-extending, circumferentially-spaced outlet guide vanes42. As such, the fan casing40may enclose the fan rotor assembly38and its corresponding fan rotor blades44. Moreover, a downstream section46of the fan casing40may extend over an outer portion of the core engine14so as to define a secondary, or by-pass, airflow conduit48that provides additional propulsive jet thrust.

It should be appreciated that, in several embodiments, the second (low pressure) drive shaft34may be directly coupled to the fan rotor assembly38to provide a direct-drive configuration. Alternatively, the second drive shaft34may be coupled to the fan rotor assembly38via a speed reduction device37(e.g., a reduction gear or gearbox) to provide an indirect-drive or geared drive configuration. Such a speed reduction device(s) may also be provided between any other suitable shafts and/or spools within the engine10as desired or required.

During operation of the engine10, it should be appreciated that an initial air flow (indicated by arrow50) may enter the engine10through an associated inlet52of the fan casing40. The air flow50then passes through the fan blades44and splits into a first compressed air flow (indicated by arrow54) that moves through conduit48and a second compressed air flow (indicated by arrow56) which enters the booster compressor22via the compressor inlet20. The pressure of the second compressed air flow56is then increased and enters the high pressure compressor24(as indicated by arrow58). After mixing with fuel and being combusted within the combustor26, the combustion products60exit the combustor26and flow through the first turbine28. Thereafter, the combustion products60flow through the second turbine32and exit the exhaust nozzle36to provide thrust for the engine10.

Referring now toFIGS.2-4, one embodiment of a system100for cleaning a gas turbine engine10is illustrated in accordance with aspects of the present subject matter. Specifically,FIG.2illustrates a simplified view of a wash stand102and various other components of the disclosed system100.FIG.3illustrates a side, cross-sectional view of portions of the gas turbine engine10shown inFIG.1and the wash stand102shown inFIG.2, particularly illustrating the wash stand102positioned adjacent to the front or forward end of the gas turbine engine10to allow a cleaning fluid to be injected therein. Additionally,FIG.4illustrates a simplified, radial view of a nozzle110of the disclosed system100as well as a plurality of the fan blades44of the gas turbine engine10, particularly illustrating the differing tangential orientations of the fan blades44and the nozzle110relative to the engine centerline12.

As particularly shown inFIG.2, the system100may include a wash stand102configured to be in fluidly coupled to a fluid surface104(e.g., via a suitable hose or fluid conduit106). In general, the wash stand102may include a base frame108and a plurality of fluid injection nozzles110supported by the base frame108. The base frame108may be formed from a plurality of structural members112,114configured to vertically support the nozzles110relative to the ground116. For example, as shown inFIG.2, the base frame108may include one or more frame members112configured to be coupled to the nozzles110(e.g., via a nozzle manifold118) and one or more stand members114supported on the ground116, with the stand member(s)114being configured to be coupled to the frame member(s)112so as to maintain the base frame108vertically upright relative to the ground116. In the illustrated embodiment, the stand members114are shown as being positioned directly onto the ground116. However, in other embodiments, a plurality of casters or wheels may be positioned between the stand members114and the ground116to allow the wash stand102to be rolled across the ground116.

It should be appreciated that the specific configuration of the base frame108may be selected such that a vertical height120of the wash stand102corresponds to a suitable height for aligning the nozzles110relative to the gas turbine engine10. For instance, as shown inFIG.3, the dimensions/configuration of the structural member(s)112,114of the base frame108may be selected such that the base frame108is configured to support the nozzles110at a vertical location relative to the ground116that allows the nozzles110to be positioned adjacent to the inlet52of the fan casing40when the base frame108is placed on the ground108proximal to the front or forward end of the engine10. In this regard, it should also be appreciated that the dimensions/configuration of the structural member(s)12,114may be adjustable, as desired or as necessary, to accommodate engines located at differing vertical heights relative to the ground116. For instance, as indicated by arrow122inFIG.2, a length of one or more of the frame member(s)112may be varied (e.g., using a telescoping configuration) to allow the vertical height120of the wash stand102to be adjusted.

In several embodiments, the fluid injection nozzles110may be coupled to the base frame108so as to form an annular array of nozzles for injecting a cleaning fluid through the inlet52of the fan casing44and into the interior of the gas turbine engine10. In such embodiments, the wash stand102may be configured to be positioned relative to the gas turbine engine10such that that a centerline124(FIG.3) of the annular array of nozzles110is generally aligned with the centerline12of the engine10. As such, each nozzle110may generally be positioned at the same radial location relative to the engine centerline12.

As shown inFIG.2, in one embodiment, each nozzle110may be coupled to the base frame108via a ring-shaped nozzle manifold118, with the various nozzles110being spaced apart circumferentially from one another around the manifold118. In such an embodiment, each nozzle110may be provided in flow communication with a fluid flow path defined within the interior of the manifold118such that all of the nozzles110are supplied with cleaning fluid via a common fluid line. For example, as shown inFIG.2, a fluid conduit106may be provided between the fluid source104and the manifold118. As such, cleaning fluid supplied from the fluid source105may be directed through the fluid conduit106and into the manifold118for subsequent delivery to each of the nozzles110.

It should be appreciated that, in one embodiment, the manifold118may be configured to be separately coupled to the base frame108, such as by welding the manifold118to one or more of the frame members112or by coupling the manifold118to the base frame108via suitable mechanical fasteners. Alternatively, the manifold118may be formed integrally with or otherwise form part of the base frame108.

It should also be appreciated that the fluid source104may generally correspond to any suitable fluid source capable of supplying a cleaning fluid to the wash stand102. In several embodiments, the fluid source104may be configured to pressurize the cleaning fluid for subsequent delivery to the nozzles110. For instance, as shown inFIG.2, the fluid source104may correspond to a mobile cleaning unit that includes a pump126configured to receive cleaning fluid from a tank or reservoir128located within the unit (or from a source external to the cleaning unit) and pressurize the fluid to a suitable fluid pressure. Specifically, in one embodiment, the cleaning fluid may be supplied to the nozzles110at a pressure ranging from about 60 pounds per square inch (psi) to about 900 psi, such as from about 100 psi to about 700 psi or from about 200 psi to about 400 psi and any other suitable subranges therebetween. As will be described below, such fluid pressure may be varied, as necessary or desired, to ensure that the cleaning fluid expelled from the nozzles110is directed past the fan blades44and into the compressor inlet20. Moreover, the fluid pressure, in combination with the number and orifice size of the nozzles110, may determine the amount of cleaning fluid injected into the engine10. In general, it may be desirable to maximize the flow amount without inducing any operability issues, such as flameout or stall, for embodiments in which the engine is running during performance of the cleaning operation.

Additionally, it should be appreciated that the cleaning fluid used within the system100may generally correspond to any suitable fluid. For instance, the cleaning fluid may correspond to a liquid, gas and/or any combination thereof (e.g., foam). In a particular embodiment, the cleaning fluid may correspond to water (e.g., distilled water) or any other water-based liquid (e.g., a solution/mixture containing water and a cleaning agent or any other suitable additive).

Referring particularly toFIGS.3and4, in several embodiments, the fluid injection nozzles110may be configured to be oriented relative to the centerline12of the engine10such that the cleaning fluid expelled from each nozzle110is directed through the fan casing40and into the compressor inlet20. For example, each nozzle110may be oriented radially inwardly relative to the engine centerline12such that the cleaning fluid expelled from the nozzles110is directly along a flow path (indicated by arrows130inFIG.3) having a radially inward component. Specifically, as shown inFIG.3, each nozzle110may extend both axially aft and radially inwardly at a radial angle132defined relative to the engine centerline12. In such an embodiment, the radial angle132of each nozzle110may be selected based on the relative radial locations of the nozzles110and the compressor inlet120to provide the desired flow path130for directing the cleaning fluid through the fan casing40and into the compressor inlet20.

It should be appreciated that, in several embodiments, the radial orientation of the nozzles110may be adjustable to accommodate differing engine configurations. For example, for an engine having a smaller or larger fan rotor radius, the radial angle132of each nozzle110may be adjusted to account for the difference in the relative radial location between the nozzles110and the compressor inlet20for the smaller/larger engine. Such adjustability of the radial orientation of the nozzles110may be achieved using any suitable means and/or methodology. For instance, in one embodiment, the nozzles110may be movably coupled to the manifold118(e.g., via a pivotal or hinged coupling) to allow the orientation of each nozzle110relative to the manifold118be adjusted. Alternatively, the nozzles110may be removably coupled to the manifold118. In such instance, when nozzles110having a differing radial orientation are desired to be installed on the wash stand '01, the existing nozzles110may be removed and replaced with nozzles110having the desired radial orientation.

Additionally, as shown inFIG.4, the nozzles110may be oriented circumferentially or tangentially relative to the engine centerline12to allow the cleaning fluid to be injected past the fan blades44and into the compressor inlet20as the fan blades44are being rotated during operation of the engine10. Specifically, in several embodiments, each nozzle110may be configured to expel cleaning fluid at a tangential angle134that is oriented in the opposite direction as the corresponding pre-defined stagger angle136of the fan blades44. For example, as shown inFIG.4, each nozzle110may be oriented at a positive tangential angle134relative to the engine centerline12whereas each fan blade44may define a stagger angle136relative to the engine centerline12corresponding to a negative tangential angle. As used herein, the terms “positive tangential angle” and “negative tangential angle” are used to differentiate tangential angles defined relative to the rotational direction of the fan blades44(indicated by the arrows138inFIG.4). For example, as shown inFIG.4, the tangential angle134of the nozzle110is defined as positive since the tangential component of the angle134(indicated by arrow140) is directed in the same direction as the rotational direction138of the fan blades44. In contrast, the stagger angle136of each fan blade44is defined as a negative tangential angle since the tangential component of the angle136(indicated by arrows142) is directed in the opposite direction of the rotational direction138of the fan blades44.

It should be appreciated that the stagger angle136generally corresponds to the angle defined between a reference line extending parallel to the engine centerline12and a straight line connecting the leading and trailing edges of the fan blade44. For example, as shown inFIG.4, each fan blade44may include a pressure side144and a suction side146extending between a leading edge148and a trailing edge150. As shown in the illustrated embodiment, the leading edge148of each fan blade44“leads” or is ahead of the trailing edge150in the rotational direction138of the fan blades44, thereby defining the negative stagger angle136.

It should be appreciated that the stagger angle136of the fan blades44may generally vary as each fan blade44extends radially outwardly towards the fan casing40. However, in a particular embodiment, the stagger angle136of each fan blade44at the radial location at which the cleaning fluid is being injected past the fan blades44(e.g., radial locations152shown inFIG.3) may generally range from less than zero degrees to about −60 degrees, such as from about −10 degrees to about −50 degrees or from about −20 degrees to about −40 degrees and any other subranges therebetween.

Additionally, it should be appreciated that the tangential angle134associated with each nozzle110as well as the pressure of the cleaning fluid supplied to the nozzles110may generally be selected so as to ensure that the cleaning fluid is expelled from the nozzles110at a suitable fluid velocity and tangential orientation for allowing all or a significant portion of the fluid to be directed between the rotating fan blades44and into the compressor inlet20. In this regard, the tangential angle134and fluid pressure required to achieve such a result may vary depending on the engine configuration, namely the stagger angle134of the fan blades44and the fan rotor radius, as well as the rotor speed at which the fan blades44are being rotated during the performance of the cleaning operation. Thus, in several embodiments, the tangential orientation of the nozzles110and/or the pressure of the cleaning fluid supplied to the nozzles110may be adjusted to provide the desired flow characteristics for the cleaning fluid being expelled from the nozzles110. For instance, in one embodiment, the tangential orientation of the nozzles110may be fixed relative to the manifold118. In such an embodiment, the pressure of the fluid supplied to the nozzles110may be adjusted, as necessary, such that the fluid velocity of the cleaning fluid expelled from the nozzles110is sufficient to allow the cleaning fluid to be injected past the rotating fan blades44and into the compressor inlet20. Alternatively, the tangential orientation of the nozzles110may be adjustable relative to the manifold118, such as by providing a pivotal or hinged connection between the nozzles110and the manifold118. In such instance, the tangential orientation of the nozzles110may be adjusted, either alone or in combination with corresponding pressure adjustments, to ensure that the cleaning fluid is directed between the fan blades44and into the compressor inlet20.

As indicated above, the tangential angle defined by the nozzles110may need to be varied as a function of numerous turbine parameters, including the rotor speed of the engine10during the performance of the cleaning operation. However, in general, the tangential angle134defined by each nozzle110may vary from greater than zero degrees to about 60 degrees when the engine is operating at a minimum rotor speed or higher (e.g., a rotor speed equal to greater than a rotor speed associated with a dry motoring speed, an idle speed and/or a partial throttle speed for the associated engine10), such as a tangential angle ranging from about 10 degrees to about 50 degrees or from about 20 degrees to about 40 degrees and/or any other subranges therebetween.

Additionally, it should be appreciated that, in several embodiments, the tangential orientation and/or radial orientation of the nozzles110may be adjusted as a function of the rotor speed at which the engine is running during performance of the cleaning operation. For instance, the nozzles110may be configured to be set at a predetermined tangential angle134and/or a predetermined radial angle132based on the rotor speed at which the engine is being operated. Such an adjustment to the orientation of the nozzles110may be made independent of or in combination to any angular adjustments due to the engine radial size. For example, in one embodiment, the nozzles110may be configured to be set at a predetermined tangential angle134and/or a predetermined radial angle132based on a combination of the rotor speed and the fan radius.

Referring now toFIG.5, a flow diagram of one embodiment of a method200for cleaning a gas turbine engine is illustrated in accordance with aspects of the present subject matter. In general, the method200will be discussed herein with reference to the gas turbine engine10described above with reference toFIG.1and the system100described above with reference toFIGS.2-4. However, it should be appreciated by those of ordinary skill in the art that the disclosed method200may generally be implemented with gas turbine engines having any other suitable engine configuration and/or with systems having any other suitable system configuration. In addition, althoughFIG.5depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

As shown inFIG.5, at (202), the method200may include positioning a wash stand having a plurality of fluid injection nozzles relative to the gas turbine engine. For example, the disclosed wash stand102may be positioned adjacent to the front or forward end of the gas turbine engine10such that the nozzles110are configured to inject cleaning fluid through the fan casing40of the engine10. As described above with reference toFIG.3, in one embodiment, the wash stand102may be positioned relative to the gas turbine engine10such that the centerline124of the annular array of nozzles110is generally aligned with the engine centerline12. It should be appreciated that the wash stand102may be positioned relative to the engine10by moving the wash stand102relative to the engine10or by moving the engine10relative to the wash stand102.

Additionally, as (204), the method200may include operating the gas turbine engine such that a plurality of fan blades of the engine are rotated in a rotational direction about the engine centerline. Specifically, as indicated above, the engine10may be running during the performance of the disclosed cleaning methodology, which may allow the cleaning fluid expelled from the nozzles110to be both heated and pressurized as the fluid is directed through the engine core14. In several embodiments, the gas turbine engine10may be operated at an operational speed at or above a minimum threshold speed for the engine10. For instance, the minimum threshold speed may correspond to a rotor speed that is equal to or greater than a rotor speed associated with a dry motoring speed, an idle speed and/or a partial throttle speed for the associated engine10.

Referring still toFIG.5, at (206), the method200may include supplying a cleaning fluid from a fluid source to the nozzles of the wash stand. Specifically, as indicated above, the wash stand102may be fluidly coupled to a suitable fluid source104(e.g., a mobile cleaning unit). As such, cleaning fluid may be directed from the fluid source104to the wash stand102(e.g., via a suitable fluid conduit106). Additionally, as described above with reference toFIGS.2and3, the various nozzles110may, in one embodiment, be fluidly coupled to a common nozzle manifold118. In such an embodiment, the cleaning fluid supplied from the fluid source104may be directed into the manifold118for subsequent delivery to the nozzles110.

Moreover, at (208), the method200may include injecting the cleaning fluid from the nozzles through a fan casing of the engine as the fan blades are being rotated such that the cleaning fluid is directed past the fan blades and into a compressor inlet of the engine. Specifically, as indicated above, the radial and/or tangential orientation of the nozzles relative110to the engine centerline12may be selected such that the cleaning fluid expelled from the nozzles110is directed between the rotating fan blades44and into the compressor inlet20. For instance, as described above with reference toFIG.4, the nozzles110may be oriented at a positive tangential angle134relative to the engine centerline12(as opposed to the negative tangential or stagger angle136of the fan blades44) to ensure that the cleaning fluid is directed at a suitable trajectory to allow the fluid to be injected unabated through the fan blades44.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.