Turbine engine filter screen

Abstract

A strainer for an aviation gas turbine engine includes a plurality of first filaments and a plurality of second filaments. The plurality of second filaments together with the plurality of first filaments define a plurality of openings. The plurality of first filaments and the plurality of second filaments define a first arrangement in which the plurality of first filaments are perpendicular to the plurality of second filaments. When a force is applied to the screen, at least some of the plurality of first filaments and at least some of the plurality of second filaments are configured to translate from a first arrangement to a second arrangement in which a size of at least one of the openings is configured to change from a first size to a second size.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Polish patent application serial number P.446463 filed on October 23, 2023. Technical Field

[0003] The present invention relates to an aviation gas turbine engine and a structure for regulating airflow. Background Art

[0004] Inlet screens for foreign object debris (“FOD”) protection prevent potential damage and blockages that can be caused by FOD and ice. Conventional screens create resistance as air passes through the screen, which affects the efficiency of the engine. An inlet screen is needed that can address these challenges. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A full and enabling disclosure of the present invention, including the best mode thereof, is set forth in the specification to those skilled in the art, with reference to the accompanying drawings, wherein:

[0006] Figure 1 A is a view of a filter screen of an aircraft gas turbine engine in a first arrangement.

[0007] Figure 1 B is Figure 1 Detailed view of the filter screen of A.

[0008] Figure 2A is a view of the filter in a second arrangement.

[0009] Figure 2B yes Figure 2A Detailed view of the filter.

[0010] Figure 3 is a view of the filter in a third arrangement.

[0011] Figure 4 is a side view of an air inlet assembly of an aircraft gas turbine engine. DETAILED DESCRIPTION

[0012] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are shown in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. The same or similar designations in the drawings and description have been used to refer to the same or similar parts of the present disclosure.

[0013] As used herein, the term "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or better than other implementations. In addition, unless expressly stated otherwise, all embodiments described herein should be considered exemplary.

[0014] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0015] For example, the term “at least one” in the context of “at least one of A, B, and C” means only A, only B, only C, or any combination of A, B, and C.

[0016] The phrases "X to Y" and "between X and Y" each refer to a numerical range including the endpoints (ie, refer to a numerical range that includes X and Y).

[0017] The term "oblique" means "an angle other than 0 or 90 degrees," and two elements are "oblique" if the angle formed between them is not a right angle, or if they are not parallel or co-linear.

[0018] The term "arrangement" means a "pattern" or "specified positioning of elements" within an object.

[0019] Ordinal numbers such as "first," "second," and "third" are descriptive only and do not indicate importance, order, or priority.

[0020] The present disclosure generally relates to an inlet screen for an aviation gas turbine engine. Since conventional inlet screens need to solve FOD protection issues and still allow air to pass, a screen is designed that provides both benefits to improve engine operation when engine space is limited.

[0021] To address these challenges, a filter screen for an aviation gas turbine engine includes a plurality of first filaments and a plurality of second filaments. Each first filament is arranged in a transverse direction and is arranged in parallel with other first filaments. Each second filament is arranged in a longitudinal direction and is arranged in parallel with other second filaments. A plurality of second filaments together with a plurality of first filaments define a plurality of openings. A plurality of first filaments and a plurality of second filaments define a first arrangement, in which a plurality of first filaments are perpendicular to a plurality of second filaments. When a force is applied to the filter screen, at least some of the plurality of first filaments and at least some of the plurality of second filaments are configured to translate from the first arrangement to the second arrangement, and in the second arrangement, the size of at least one of the openings is configured to change from the first size to the second size.

[0022] Because the first and second filaments can slide relative to each other to the second arrangement, the opening defined by the first and second filaments is adjustable, for example, to provide a specific airflow to the engine. The force applied to the screen can use fewer mechanical parts than a conventional airflow regulator, thereby reducing the overall weight and space used in the engine. In addition, the screen formed by the first and second filaments provides FOD protection and can be controlled to remove debris and ice accumulation.

[0023] In addition, it should be understood that the FOD ingestion risk of a gas turbine engine (e.g., a turboprop engine) may change under different operating conditions. For example, at takeoff, the FOD ingestion risk may be higher than at cruise. It is noteworthy that an inlet filter can be positioned on the inlet of a turboprop engine to reduce the risk of FOD ingestion. If designed to prevent the ingestion of FOD at takeoff, the filter may create unnecessary resistance to the inlet airflow during cruise. The present disclosure provides an inlet filter that can change the opening size (e.g., during different operating periods) to reduce the resistance to the inlet airflow during operating conditions with a lower risk of FOD ingestion.

[0024] Referring now to the drawings, wherein like numerals represent like elements throughout the drawings, the filter screen 10 is shown in a first arrangement. Figure 1 The first arrangement shown in A-1B can be a "rectangular" arrangement, such that the plurality of first filaments 12 and the plurality of second filaments 14 are arranged in a generally rectangular shape. In the rectangular arrangement, the filter screen 10 defines four corners and two sets of opposite parallel sides that form right angles at the corners. That is, the filter screen 10 includes two sides 18 arranged along the transverse direction X and two sides 20 arranged along the longitudinal direction Y. Alternatively, the filter screen 10 can be a different shape, such as a disc, annular, circular, triangular, quadrilateral, or another polygonal shape.

[0025] like Figure 1 As shown in A-1B, a plurality of first filaments 12 are arranged in a transverse direction X, and a plurality of second filaments 14 are arranged in a longitudinal direction Y. A plurality of first filaments 12 are perpendicular to a plurality of second filaments 14 to form a rectangular shape of a first arrangement. The first filament 12 and the second filament 14 are thin sheets (e.g., wires, strips, or rods) made of suitable materials (e.g., metals or composite materials). When the filter screen 10 moves to a different arrangement, the elongated shape of the material allows the first filament 12 and the second filament 14 to slide with each other. The first filament 12 and the second filament 14 can have substantially the same thickness, i.e., the diameter or specification of the cross section is similar. For example, the thickness of the first filament 12 and the second filament 14 can be 0.5 millimeters to 3 millimeters (mm).

[0026] Each pair of adjacent second filaments 14 defines a spacing, represented by variable A. This spacing is a "transverse" spacing, i.e., the spacing in the transverse direction X. Each pair of adjacent first filaments 12 defines a spacing, represented by variable B. This spacing is a "longitudinal" spacing, i.e., the spacing in the longitudinal direction Y. In this case, the spacing between adjacent first filaments 12 may be a "first spacing", and the spacing between adjacent second filaments 14 may be a "second spacing". Figure 1 In the embodiment of FIG. 1B, the spacings A and B between the first filaments 12 and the second filaments 14 are substantially the same throughout the filter screen 10, so that the same spacing A is defined between each pair of first filaments 12, and the same spacing B is defined between each pair of second filaments 14. In another embodiment not shown in the figure, at least some of the first filaments 12 may have a spacing A different from other first filaments 12, or at least some of the second filaments 14 may have a spacing B different from other second filaments 14.

[0027] like Figure 1 As shown in FIG. 1B , the plurality of first filaments 12 and the plurality of second filaments 14 together define a plurality of openings 16. Each opening 16 has a boundary 22 defined by a pair of adjacent first filaments 12 and a pair of adjacent second filaments 14. Figure 1 In the example shown in B, the opening 16 is substantially rectangular, with a pair of first filaments 12 defining two opposite sides in the transverse direction X, and a pair of second filaments 14 defining two opposite sides in the longitudinal direction Y. The opening 16 is configured to allow air to pass through, for example, into the inlet of an air duct as described below. The first filaments 12 are woven between the second filaments 14 to define the opening 16. By weaving the first filaments 12 between the second filaments 14, the sinusoidal shape of the woven first and second filaments 12, 14 holds the first and second filaments 12, 14 against each other in a mesh shape.

[0028] The size of each of the plurality of openings 16 is based on a respective lateral spacing A and a respective longitudinal spacing B. Figure 1 In an example of B, the dimension may be an area defined by the product AB of the lateral spacing and the longitudinal spacing. In one example, the lateral spacing A may be substantially equal to the longitudinal spacing B, so that the opening 16 has a substantially square shape. In another example, the lateral spacing A may be different from the longitudinal spacing B, so that the opening 16 has a substantially rectangular shape. The ratio of the lateral spacing A to the longitudinal spacing B defines an opening aspect ratio A / B, which may be in the range of 0.2 to 1.0. The lateral spacing A and the longitudinal spacing B may each be in the range of 0.5 mm to 100 mm. The lateral and longitudinal spacings A, B and the opening aspect ratio may be determined to allow a specific airflow to pass through the filter screen 10 in the first arrangement.

[0029] The actuator 24 may be attached to the filter screen 10. Figure 1In the example of A-1B, the actuator 24 is a linear actuator. Alternatively, the actuator 24 can be a different type of actuator 24, such as a rotary actuator. The actuator 24 includes a translator 26, such as a rod or bar, and a driver 28, such as a motor or solenoid, which causes the translator 26 to slide along a track 30. For clarity, only one of the tracks 30 is shown in the figure, and it should be understood that the construction of each actuator 24 in these examples is similar. The converter 26 is attached to the filter 10 at the attachment point 32 by a suitable fastener (such as an adhesive, welding, or friction fit). The actuator 24 can be fixed to another component (such as a wall) to allow the actuator 24 to move the filter 10 relative to the component.

[0030] The translator 26 is attached to the filter screen 10 in such a manner that when the driver 28 translates the translator 26 along the track 30, the filter screen 10 moves with the translator 26. That is, the actuator 24 is configured to apply a force to a portion of the filter screen 10, and the force pushes or pulls the first filaments 12 and the second filaments 14. Since the first filaments 12 and the second filaments 14 are woven to slide against each other, the first filaments 12 and the second filaments 14 are translated by applying the force. The force translates the filter screen 10 to a second arrangement as described below, in which the plurality of first filaments 12 are arranged obliquely relative to the plurality of second filaments 14.

[0031] A plurality of actuators 24 may be attached to the screen 10 at respective attachment points 32, such as Figure 1 Two actuators 24 and two attachment points 32 are shown in A. The attachment points 32 can be arranged near the corners so that the force applied by the actuators 24 is substantially along the diagonal line D connecting the opposite corners. Alternatively, when the filter screen 10 is rectangular, the actuators 24 can be attached to each of the four corners. Alternatively, when the filter screen 10 is non-rectangular, the actuators 24 can be attached at suitable locations to move the filter screen 10 to a specific arrangement.

[0032] Reference now Figure 2A-2B , shows a second arrangement of the filter screen 10. In this arrangement, the actuator 24 applies a force F at the attachment point 32 to pull the filter screen 10, thereby translating at least some of the plurality of first filaments 12 and at least some of the plurality of second filaments 14. In this example, the relative corners to which the actuator 24 is attached move away from each other, thereby increasing the distance between the attachment points 32. As the relative corners move away from each other, the other two relative corners are pushed toward each other. That is, the translation of the first filament 12 and the second filament 14 by the actuator 24 causes the first filament 12 and the second filament 14 to move relative to each other. Figure 1The arrangement rotates. The rotation guides the first filament 12 and the second filament 14 to move along an axis (not shown) defined between the attachment points 32. Therefore, more lengths of the first filament 12 and the second filament 14 are aligned with the axis, and less lengths of the first filament 12 and the second filament 14 are arranged perpendicular to the axis. This results in the shape of the filter screen 10 being a parallelogram, having a longer diagonal D aligned with the axis of the attachment point and a shorter diagonal E perpendicular to the axis of the attachment point 32. The specific lengths of the diagonals D and E depend on the aspect ratio of the filter screen 10, that is, the ratio between the length and width of the filter screen 10. In this example, the direction of force F is aligned with the orientation of the actuator 24, the actuator 24 is at a certain angle relative to the diagonal D, and the actuator 24 can be arranged in a suitable position relative to the diagonal D to provide a specific direction for the force F.

[0033] In the second arrangement, the size of at least one of the openings 16 is changed to a second size. That is, the oblique arrangement of the first filament 12 and the second filament 14 as described above reduces the area of ​​the opening 16 relative to the vertical arrangement of the first filament 12 and the second filament 14, and thus the second size is smaller than the first size. The first size of the opening 16 of the first arrangement allows a specific airflow to pass, while the second size of the opening 16 of the second arrangement allows a different airflow to pass. Therefore, by adjusting the size of the opening 16, the airflow through the filter screen 10 can be controlled by the actuator 24.

[0034] Each of the plurality of openings 16 defines an inclination, represented by the variable C. In this context, as described above, the inclination is the angle defined between one of the first filaments 12 defining the boundary 22 of the corresponding opening 16 and one of the second filaments 14 defining the boundary 22 of the corresponding opening 16. Figure 1 In B, the inclination of each of the plurality of openings 16 is 90 degrees, and each opening 16 is substantially rectangular. Figure 2B In the embodiment, the inclination of each of the plurality of openings 16 is different from 90 degrees, and the shape of each opening 16 is a parallelogram. Specifically, Figure 2B An inclination greater than 90 degrees, i.e. an obtuse inclination, is shown. The inclination can be, for example, a value from 20 to 160 degrees. The size of each opening 16 can be determined based on the spacing A, B and the inclination C: ABsin(C). Since the sine of 90 degrees is 1, the expression for the size of the opening 16 gives the size value of the rectangular opening 16 as AB, which is the same as above. When the inclination of the opening 16 is different from 90 degrees, the arrangement is a "tilted" arrangement.

[0035] Reference now Figure 3, the actuator 24 moves the filter screen 10 to the third arrangement. The actuator 24 applies a force F' to push the attachment points 32 toward each other, and the third arrangement is another inclined arrangement. In this example, the relative corners to which the actuator 24 is attached move toward each other, thereby reducing the distance between the attachment points 32. That is, the distance along the diagonal D is less than the distance along the diagonal E. In the third arrangement, the inclination of the opening is less than 90 degrees, that is, an acute angle inclination. Since the first filament 12 is inclined relative to the second filament 14, the opening 16 is again substantially shaped as a parallelogram, similar to the opening 16 in the second arrangement.

[0036] Actuator 24 can be moved by translating translator 26 back and forth along its respective track 30. Figure 1 A-3 moves the filter screen 10 between different arrangements. That is, the actuator 24 can vibrate the filter screen 10 between the first, second, and third arrangements or between different arrangements. During the vibration of the filter screen 10, the movement of the first filaments 12 and the second filaments 14 can remove contaminants (e.g., ice and dirt) that may accumulate on the filter screen 10 and block one or more openings 16. Removing contaminants by vibrating the filter screen 10 (sometimes referred to as a "de-icing" process) can provide a more consistent airflow through the filter screen 10 because the openings 16 are no longer blocked by contaminants.

[0037] refer to Figure 4 , an air duct assembly 40 for a gas turbine engine of an aircraft is shown. The gas turbine engine is more specifically a turboprop engine, such as a reverse flow turboprop engine.

[0038] The air duct assembly 40 provides air from outside the aircraft to the gas turbine engine. The air duct assembly 40 includes an air inlet 42, a first filter 44, a second filter 46, an actuator 48, and a controller 50. The air inlet 42 is an annular opening that allows air flow to the gas turbine engine. The first filter 44 and the second filter 46 are similar in construction to the above-described filter 10, including respective first and second filaments ( Figure 4 4. The first filter screen 44 and the second filter screen 46 are attached to the air inlet 42 and extend circumferentially around the air inlet 42. The actuator 48 includes a translator, a drive, and a track as described above and is not shown in FIG. Figure 4 Not shown.

[0039] The air duct assembly 40 controls the airflow through the air inlet 42 by activating the controller 50 to move the first filter 44 and the second filter 46 from their respective first arrangements (actuators 48 shown in solid lines) to their respective second arrangements (actuators 48 shown in dashed lines). In the second arrangement, as described above, the size of the respective openings of the first filter 44 and the second filter 46 is adjusted to allow a specified airflow to pass through the first filter 44 and the second filter 46. Specifically, in the second arrangement, the first filter 44 and the second filter 46 can be configured to reduce the airflow through the air inlet 42 relative to a default airflow, which is defined as the airflow when the first filter 44 and the second filter 46 are in the first arrangement. In addition, the first filter 44 and the second filter 46 straighten the airflow by forcing air through the openings. These openings suppress high-pressure airflow and allow low-pressure airflow to pass, which results in the airflow through the first filter 44 and the second filter 46 being more uniform than the airflow outside the first filter 44 and the second filter 46.

[0040] The controller 50 includes a processor and a memory, and the memory includes instructions that can be executed by the process. Specifically, the controller 50 communicates with the actuator 48, such as a wired or wireless connection, to provide instructions to the actuator 48. The controller 50 is configured to provide instructions to actuate the actuator 48 to translate one or more of the first filter 44 or the second filter 46 to the corresponding second arrangement, thereby adjusting the airflow through the air inlet 42. That is, after receiving the instruction from the controller 50, the actuator 48 moves the translator to the specified position, thereby moving the first filter 44 and the second filter 46 attached with the translator to the second arrangement. For clarity, Figure 4 The controller 50 in FIG. 5 is shown close to the actuator, and it should be understood that the controller 50 may be disposed at a suitable location in the aircraft.

[0041] exist Figure 4In the exemplary air duct assembly 40 of FIG. 4 , an actuator 48 is shown. The actuator 48 is fixed to the outside of the air inlet 42 and translates the first filter 44 and the second filter 46. In one example, the actuator 48 moves the first filter 44 and the second filter 46 away from the actuator 48, toward the air inlet 42 and to the second arrangement. In another example, the actuator 48 translates the first filter 44 and the second filter 46 circumferentially to the second arrangement. Fixing the actuator 48 to the outside of the air inlet 42 allows air to flow through the air inlet 42 without being hindered by the actuator 48. Alternatively, the actuator 48 can be disposed in the air inlet 42 (not shown) and can pull the first filter 44 and the second filter 46 toward the actuator 48 and into the air inlet 42. Placing the actuator 48 in the air inlet 42 allows the actuator 48 to be closer to the first filter 44 and the second filter 46 than when it is disposed outside the air inlet 42. Alternatively, the air duct assembly 40 may include a plurality of actuators 48, each in communication with the controller 50 to translate one or more of the first filter 44 or the second filter 46 to the second arrangement. The plurality of actuators 48 may be disposed circumferentially about the air inlet 42.

[0042] The first filter 44 and the second filter 46 meet at a connection point 52 (i.e., the point where the first filter 44 contacts the second filter 46). Figure 4 In the exemplary air duct assembly of FIG. 5 , the connection point 52 is a common edge of the first filter 44 and the second filter 46, and the connection point 52 extends around the annular air inlet 42. The actuator 48 is attached to the first filter 44 and the second filter 46 at the connection point 52. When the controller 50 actuates the actuator 48, the translator applies a force and moves the connection point 52, thereby translating the first filter 44 and the second filter 46 to their respective second arrangements.

[0043] Alternatively, not shown in the figure, the air duct assembly 40 may include a single filter screen extending over the air inlet 42. The single filter screen may have a suitable shape, such as an arc, so that there is no connection point. The actuator 48 is attached to the single filter screen at a suitable attachment point and moves the filter screen to the second arrangement according to the instructions of the controller 50. Alternatively, the air duct assembly 40 may include multiple filters of suitable shapes to control the airflow through the air inlet 42.

[0044] In addition to the air duct assembly 40 shown in the figure, the filter (e.g., filter 10 or the first filter 44 and the second filter 46) can be used for other applications. In one example, the filter can be incorporated in a heat exchanger system, passing through a heat exchanger pipe to avoid overcooling of the oil. In this form, the filter can be actuated to limit the cooling airflow, thereby maintaining the minimum temperature of the oil. In another example, the filter can be incorporated into a fluid system to assist or replace a valve. In this form, an arrangement can allow a certain fluid to flow through the filter, and when the filter moves to a different arrangement, the smaller size of the opening can slow down or stop the fluid from flowing through the filter. Therefore, the filter acts like a valve, selectively providing a specified fluid flow.

[0045] The following topics provide further aspects:

[0046] A filter screen for an aviation gas turbine engine, the filter screen comprising: a plurality of first filaments, each of the plurality of first filaments being arranged in a transverse direction and being arranged in parallel with other first filaments in the plurality of first filaments; and a plurality of second filaments, each of the plurality of second filaments being arranged in a longitudinal direction and being arranged in parallel with other second filaments in the plurality of second filaments, the plurality of second filaments together with the plurality of first filaments defining a plurality of openings, wherein the plurality of first filaments and the plurality of second filaments define a first arrangement, in which the plurality of first filaments are perpendicular to the plurality of second filaments, wherein when a force is applied to the filter screen, at least some of the plurality of first filaments and at least some of the plurality of second filaments are configured to translate from the first arrangement to a second arrangement, in which the size of at least one of the openings is configured to change from a first size to a second size.

[0047] The screen of any one or more of the clauses herein, wherein the second dimension of the at least one of the openings is smaller than the first dimension of the at least one of the openings.

[0048] A filter according to any one or more of the clauses herein, wherein each of the plurality of openings defines an inclination, the inclination being an angle between one of the first filaments defining a boundary of the corresponding opening and one of the second filaments defining the boundary of the corresponding opening, the inclination of each of the plurality of openings in the first arrangement being 90 degrees, and the inclination of each of the plurality of openings in the second arrangement being different from 90 degrees.

[0049] The filter screen of any one or more of the clauses herein, wherein each of the plurality of first filaments is woven between each of the plurality of second filaments to define the plurality of openings.

[0050] A filter according to any one or more of the clauses herein, wherein each adjacent pair of first filaments in the plurality of first filaments defines a pair of first filaments having a first spacing therebetween, and each adjacent pair of second filaments in the plurality of second filaments defines a pair of second filaments having a second spacing therebetween, and a size of each of the plurality of openings is based on a corresponding first spacing between the pair of first filaments defining the boundaries of the openings and a corresponding second spacing between the pair of second filaments defining the boundaries of the openings.

[0051]

[0013] The filter screen of any one or more of the clauses herein, wherein the respective first spacing of at least one of the plurality of openings is different than the respective second spacing of the at least one of the plurality of openings.

[0052]

[0013] The filter screen of any one or more of the clauses herein, wherein the respective first spacing of at least one of the plurality of openings is substantially equal to the respective second spacing of the at least one of the plurality of openings.

[0053] The filter screen of any one or more of the clauses herein, wherein a ratio of the respective first spacing of the openings to the respective second spacing of the openings defines an opening aspect ratio.

[0054] The filter screen according to any one or more of the clauses herein, wherein the opening aspect ratio is in the range of 0.2 to 1.0.

[0055] The filter screen according to any one or more of the clauses herein, wherein the first spacing and the second spacing are both in the range of 0.5 mm to 100 mm.

[0056] A filter according to any one or more of the clauses herein, wherein, when a second force is applied to the filter, at least some of the plurality of first filaments and at least some of the plurality of second filaments are configured to translate from the first arrangement to a third arrangement, wherein a size of at least one of the openings in the third arrangement is configured to change from a first size to a third size.

[0057] A component comprises: a filter screen, the filter screen comprising a plurality of first filaments and a plurality of second filaments, the plurality of first filaments being arranged perpendicular to the plurality of second filaments to define a first arrangement, the first arrangement comprising a plurality of openings defined between the plurality of first filaments and the plurality of second filaments; and an actuator, the actuator being attached to the filter screen and configured to move a portion of the filter screen to translate the filter screen to a second arrangement, in which the plurality of first filaments are arranged obliquely to the plurality of second filaments, wherein a corresponding second size of each of the plurality of openings in the second arrangement is different from a corresponding first size of each of the plurality of openings in the first arrangement.

[0058] The assembly of any one or more of the clauses herein, wherein the actuator is configured to oscillate the filter between the first arrangement and the second arrangement.

[0059] A component according to any one or more of the clauses herein, wherein each of the plurality of openings defines an inclination, the inclination being an angle between a first filament among the plurality of first filaments defining a boundary of the opening and a second filament among the plurality of second filaments defining the boundary of the opening, the inclination of each opening in the first arrangement being 90 degrees, and the inclination of each opening in the second arrangement being different from 90 degrees.

[0060] An assembly as recited in any one or more of the clauses herein, wherein the respective second sizes of the plurality of openings in the second arrangement are smaller than the respective first sizes of the plurality of openings in the first arrangement.

[0061] An assembly as described in any one or more of the clauses herein, wherein the actuator is attached to the filter screen at an attachment point.

[0062] The assembly of any one or more of the clauses herein, further comprising a plurality of actuators, each actuator of the plurality of actuators being attached to the filter at a respective attachment point.

[0063] The assembly of any one or more of the clauses herein, wherein the respective attachment point of each of the plurality of actuators is determined based on a shape of the filter screen.

[0064] An air duct assembly for a turbine engine, the air duct assembly comprising: an air inlet; a filter screen extending across the air inlet, the filter screen comprising: a plurality of first filaments arranged parallel to each other in a transverse direction; and a plurality of second filaments arranged parallel to each other in a longitudinal direction, the plurality of second filaments together with the plurality of first filaments defining a plurality of openings, wherein the plurality of first filaments and the plurality of second filaments define a first arrangement in which the plurality of first filaments are perpendicular to the plurality of second filaments, and an actuator attached to the filter screen and configured to translate the filter screen from the first arrangement to a second arrangement in which the plurality of first filaments are arranged obliquely to the plurality of second filaments, wherein in the second arrangement, respective second sizes of the plurality of openings are smaller than respective first sizes of the plurality of openings in the first arrangement, and wherein in the second arrangement, the filter screen is configured to reduce airflow through the air inlet relative to a default airflow through the air inlet.

[0065] The air duct assembly according to any one or more of the clauses herein, further comprising a controller configured to actuate the actuator to translate the filter to the second arrangement to provide a specific airflow through the air inlet.

[0066] The air duct assembly of any one or more of the clauses herein, wherein the controller is configured to actuate the actuator to oscillate the filter between the first arrangement and the second arrangement.

[0067] The air duct assembly of any one or more of the clauses herein, further comprising a second actuator attached to the filter, wherein the controller is configured to actuate the actuator and the second actuator to translate the filter to the second arrangement.

[0068] The air duct assembly according to any one or more of the clauses herein, further comprising a second filter screen attached to the filter screen to define a connection point.

[0069] An air duct assembly according to any one or more of the clauses herein, wherein the actuator is attached to the filter and the second filter at the connection point, and the actuator is configured to translate the filter and the second filter to a corresponding second arrangement when a force is applied to the filter and the second filter at the connection point.

[0070] A method for moving a filter screen of a gas turbine engine, the filter screen comprising a plurality of first filaments and a plurality of second filaments, the plurality of first filaments together defining a plurality of openings, the method comprising actuating an actuator to apply a force to the filter screen to translate the filter screen from a first arrangement to a second arrangement in which a size of at least one of the openings is configured to change from a first size to a second size.

[0071] The method of any one or more of the clauses herein, further comprising removing ice or debris from the filter screen when translating the filter screen to the second arrangement.

[0072] The method of any one or more of the clauses herein, further comprising translating the screen from the first arrangement to the third arrangement in which the size of at least one of the openings is configured to change from the first size to the third size.

[0073] The method of any one or more of the clauses herein, further comprising actuating the actuator to oscillate the filter screen between the first arrangement and the second arrangement.

[0074] A method as recited in any one or more of the clauses herein, further comprising reducing airflow through the filter when the filter is in the second arrangement.

[0075] The method according to any one or more of the clauses herein, further comprising a plurality of actuators to apply force to the filter screen.

[0076] The method according to any one or more of the clauses herein, wherein the second dimension of at least one of the openings is smaller than the first dimension of at least one of the openings.

[0077] A method according to any one or more of the clauses herein, wherein each of the plurality of openings defines an inclination, the inclination being an angle between one of the first filaments defining a boundary of the corresponding opening and one of the second filaments defining the boundary of the corresponding opening, the inclination of each of the plurality of openings in the first arrangement being 90 degrees, and the inclination of each of the plurality of openings in the second arrangement being different from 90 degrees.

[0078] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable those skilled in the art to practice the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the present disclosure 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 that do not differ substantially from the literal language of the claims.

Claims

1. A filter screen for an aviation gas turbine engine, characterized in that: The filter comprises: a plurality of first filaments, each of the plurality of first filaments being arranged in a transverse direction and arranged in parallel with other first filaments of the plurality of first filaments; and a plurality of second filaments, each of the plurality of second filaments being arranged in a longitudinal direction and parallel to other second filaments of the plurality of second filaments, the plurality of second filaments together with the plurality of first filaments defining a plurality of openings, wherein the plurality of first filaments and the plurality of second filaments define a first arrangement in which the plurality of first filaments are perpendicular to the plurality of second filaments, Wherein, when force is applied to the filter, at least some of the plurality of first filaments and at least some of the plurality of second filaments are configured to translate from the first arrangement to a second arrangement, in which the size of at least one of the openings is configured to change from a first size to a second size.

2. The filter screen according to claim 1, characterized in that: in, The second dimension of the at least one of the openings is smaller than the first dimension of the at least one of the openings.

3. The filter screen according to claim 1, characterized in that: in, Each of the multiple openings defines an inclination, which is an angle between a first filament among the first filaments defining a boundary of the corresponding opening and a second filament among the second filaments defining the boundary of the corresponding opening, the inclination of each of the multiple openings in the first arrangement is 90 degrees, and the inclination of each of the multiple openings in the second arrangement is different from 90 degrees.

4. The filter screen according to claim 1, characterized in that: in, Each of the plurality of first filaments is woven between each of the plurality of second filaments to define the plurality of openings.

5. The filter screen according to claim 1, characterized in that: in, Each adjacent pair of first filaments in the plurality of first filaments defines a pair of first filaments having a first spacing therebetween, and each adjacent pair of second filaments in the plurality of second filaments defines a pair of second filaments having a second spacing therebetween, and a size of each of the plurality of openings is based on a corresponding first spacing between the pair of first filaments defining a boundary of the opening and a corresponding second spacing between the pair of second filaments defining the boundary of the opening.

6. The filter screen according to claim 5, characterized in that: in, The respective first pitch of at least one of the plurality of openings is different from the respective second pitch of the at least one of the plurality of openings.

7. The filter screen according to claim 5, characterized in that: in, The respective first pitch of at least one of the plurality of openings is substantially equal to the respective second pitch of the at least one of the plurality of openings.

8. The filter screen according to claim 5, characterized in that: in, A ratio of the respective first pitches of the openings to the respective second pitches of the openings defines an opening aspect ratio.

9. The filter screen according to claim 8, characterized in that: in, The opening aspect ratio is in the range of 0.2 to 1.

0.

10. The filter screen according to claim 5, characterized in that: in, The first spacing and the second spacing are both in the range of 0.5 mm to 100 mm.

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