Flow body of an aircraft and aircraft

Abstract

A flow body (10) of an aircraft, comprising a flow surface (11) which is exposed to an air flow during flight of the aircraft, the flow surface (11) generating an area (24) of at least one turbulent air flow during flight of the aircraft, at least one perforated area comprising a plurality of openings (32) extending through the flow surface (11), a flow collecting chamber (14) positioned inside the flow surface (11) in fluid communication with the openings (32), and at least one suction duct (28) having a first end (27) in fluid communication with the flow collecting chamber (14) and a second end (29) comprising a suction opening (20) and arranged in the area (24) of the at least one turbulent air flow, wherein the suction opening (20) is adapted to cause a suction in the at least one suction duct (28) when the flow surface (11) is exposed to an air flow during flight, thereby causing an air flow through the plurality of openings (32). The invention provides a flow body (10) with improved air flow.

Description

[0001] The present invention relates to a flow body and an aircraft, the flow body comprising a flow surface exposed to airflow during flight of the aircraft, the aircraft including the flow body.

[0002] During flight, the fluid body provides both lift and drag to the aircraft. The drag generated by the fluid body can be partially reduced when the airflow around it remains laminar. Hybrid Laminar Flow Control (HLFC) systems can be used to increase and control the laminarity of the airflow around the fluid body, and thus reduce drag. HLFC systems reduce drag by providing suction to the boundary layer airflow of the fluid body. This increases laminar flow and therefore significantly reduces frictional drag on the aerodynamic surfaces of the fluid body. The suction generated by the HLFC system can be provided by passive devices, such as those using a low-pressure region source, or by active devices, such as those using a suction pump.

[0003] EP 3 199 450 A1 describes an example of a passive HLFC system in which a chamber is arranged on the leading edge of a wing. A perforation in the leading edge provides an opening to the chamber. A tube extending along the chamber connects to a suction opening, which is arranged in a low-pressure region during flight. The suction generated at the suction opening draws airflow through the tube from the perforation to the tube.

[0004] A flow body that includes improved airflow is required.

[0005] This objective is achieved through the features of the independent claim. Advantageous embodiments are the subject of the dependent claims and are described below.

[0006] According to the present invention, a flow body of an aircraft includes: a flow surface exposed to an airflow during flight of the aircraft, a region on the flow surface generating at least one turbulent airflow during flight of the aircraft, at least one perforated region including a plurality of openings extending through the flow surface, a collection cavity positioned inside the flow surface and in fluid communication with the openings, and at least one suction tube having a first end and a second end, the first end being in fluid communication with the collection cavity, the second end including a suction opening and arranged in the region of the at least one turbulent airflow, wherein the suction opening is adapted to induce suction in the at least one suction tube when the flow surface is exposed to an airflow during flight, thereby causing an airflow through the plurality of openings.

[0007] This invention provides a passive HLFC system with at least one suction tube that draws air from a manifold of a flow body, wherein the suction opening of the suction tube is arranged in a region of turbulent airflow near the surface of the flow body. Because the suction opening is positioned within the region of at least one turbulent airflow, interference from the suction tube and / or suction opening in the remaining laminar flow is minimized. This avoids placing the outlet in a region where laminar flow could otherwise be achieved and avoids increasing the area of ​​turbulent airflow at the flow surface. Therefore, the positioning of at least one suction tube has minimal impact in the laminar flow region, thereby reducing drag losses attributable to the turbulence generated by at least one suction tube.

[0008] During flight, regions of turbulent airflow can be generated by the flow surface itself, such as through the leading edge or through components protruding from the flow surface of the flow body. The suction opening and the collector cavity are in fluid communication via a suction pipe. During flight, the suction force generated at the suction opening by the airflow along the flow surface causes airflow from the collector cavity through the suction pipe and the suction opening. This causes airflow to enter the collector cavity through multiple openings in the perforated region. The intake of some boundary layer through the perforations (i.e., multiple openings) reduces the boundary layer thickness, thus establishing or enhancing the laminarity of the airflow.

[0009] In the example, the flow body includes multiple suction tubes.

[0010] In that example, suction is provided at multiple suction openings, so that the failure of a single suction tube does not lead to the complete failure of the HLFC system. If one of the suction tubes fails, the remaining active suction tubes can maintain airflow through the openings in the perforated area. Therefore, the airflow between the openings in the perforated area and the suction openings is improved.

[0011] According to an example, the flow surface generates multiple regions of turbulent airflow that are spaced apart from each other during the flight of the aircraft, and wherein the multiple suction pipes are arranged in the regions of turbulent airflow that are separated from each other.

[0012] The suction tubes and therefore the suction openings can be arranged such that they are spaced apart from each other in regions of turbulent airflow, which are themselves spaced apart from each other. The regions of turbulent airflow can be associated with a suction tube in a one-to-one manner. This means that each suction tube is arranged within its own region of turbulent airflow. This further reduces the turbulence effect generated by the suction tubes.

[0013] According to one example, the manifold includes multiple manifold sections, wherein each of the multiple manifold sections is arranged on a separated portion of the at least one perforated region. According to another example, the multiple suction tubes and the multiple manifold sections are associated with each other in a one-to-one ratio.

[0014] There is no need for a special tubing system that extends through the manifold and guides air from the first end of the suction tube, because multiple suction tubes can be arranged such that their suction force covers the entire manifold. Each manifold section can be covered by the first end of the suction tube to provide sufficient airflow through all openings in the perforated area.

[0015] According to the example, the manifold section is separated by a wall.

[0016] Due to the walls between the manifold sections, independent airflows can flow through the manifold sections. Each manifold section delivers airflow between the perforated area, the section on which the manifold section is arranged, and the suction pipe connected to the manifold section. This improves airflow through the manifold sections due to less turbulence within the manifold.

[0017] According to another example, the wall provides an airtight seal between the manifold sections.

[0018] The airtight seal between the manifold sections suppresses any airflow between them. This further improves airflow through the openings in the perforated area and the manifold sections.

[0019] According to an example, the at least one suction tube includes a cross-section adapted to the pressure value at the location of the suction opening in the region of the turbulent airflow.

[0020] Therefore, the suction pipes can be optimized for the airflow required to determine their placement. Furthermore, if more than one suction pipe is provided, each pipe can be optimized based on its location within the turbulent airflow region. Thus, a suction pipe placed in a region with lower pressure than another region where a separate suction pipe is placed can have a smaller cross-section. This reduces the weight of those suction pipes and adapts the airflow through them to the local pressure. Additionally, this adapts the pressure distribution within the manifold, allowing the airflow through all openings in the perforated region to be tailored to the locally required airflow at the corresponding openings in the perforated region. This further improves the airflow within the flow body and the manifold.

[0021] According to an example, the flow surface includes a turbulence-generating structure that generates the region of the at least one turbulent airflow.

[0022] Turbulence-generating structures can be any element on a flow surface that can influence airflow at that surface during flight. While such turbulence-generating structures may be inherently necessary for the design of the flow body itself, they can be detrimental because they interfere with and turbulentize the laminar airflow in contact with them. These turbulence-generating structures can take the form of one or more skin-cutouts (e.g., slat cutouts) for actuating elements, or other non-flush structures such as removable channel panels, rivets, fasteners, or gaps or steps at the intersections of adjacent components (e.g., skin panels, deflectors, hangers, etc.). The turbulence-generating structure can also include turbulence-generating elements that can be attached to the flow body to alter the lift and drag characteristics of the flow body during a given flight program. Examples include turbulence generators, vortex generators, and deflectors. The leading edge of an airfoil (e.g., an aircraft wing, winglet, horizontal stabilizer, or vertical stabilizer) can also be a turbulence-generating structure.

[0023] According to one example, the flow body can be an airfoil, such as an aircraft wing, winglet, vertical tail, or horizontal tail. According to another example, the flow body can include a leading edge facing the airflow during flight, wherein the at least one perforated area is arranged at the leading edge.

[0024] According to the example, the flow body is an airfoil, the airfoil includes a lift enhancement device, the lift enhancement device can be arranged in the flow collection cavity, wherein the lift enhancement device is preferably a Krueger lift enhancement device.

[0025] Therefore, the space used to store lift-enhancing devices during flight can be used as part of a flow collector. The flow collector can thus be multifunctional, allowing for space savings and weight reduction.

[0026] According to the present invention, an aircraft is also provided, the aircraft comprising at least one fluid body as described above.

[0027] The effects and further embodiments of the aircraft according to the present invention are similar to those described above. Therefore, the aircraft is referenced to the above description of the fluid body.

[0028] The invention is described below with reference to the accompanying drawings through exemplary embodiments.

[0029] Figure 1 The aircraft wing, serving as a fluid body, is shown.

[0030] Figure 2 It shows Figure 1 Details of the fluid body are shown.

[0031] Figure 3 It shows Figure 1 The vertical cross-section of the fluid body is shown.

[0032] Figure 4 The tail section of an aircraft with a flowing body on both the horizontal and vertical tail fins is shown.

[0033] Figure 5 An aircraft is shown that includes a fluid body at different lift-generating elements.

[0034] according to Figure 1 The flow body is indicated by reference numeral 10 in the accompanying drawings. The flow body 10 may be a component of a passive HLFC system.

[0035] The fluid body 10 can be arranged on the leading edge 18 of the aircraft wing 12. The leading edge 18 faces the airflow during flight. However, the fluid body 10 can also be arranged at different parts of the aircraft wing 12 or at different lift-generating elements of the aircraft 40.

[0036] The flow body 10 includes a flow surface 11 that is exposed to airflow during flight. This means that airflow flows along the flow surface 11 during flight, i.e., the flow surface 11 can be the outer skin of the aircraft wing 12.

[0037] When the flow surface 11 is exposed to the airflow during flight, the flow surface 11 can cause the airflow to provide lift for the aircraft 40 to rise.

[0038] The flow surface 11 may include at least one perforated region having a plurality of openings 32 in region 13, in which airflow along the flow surface 11 will remain laminar. The openings 32 may be components of a passive HLFC system to control the laminar flow of airflow along the flow surface 11.

[0039] Furthermore, the flow body may include a collection cavity 14, which is arranged below the flow surface 11, i.e., inside the flow surface 11. An opening 32 is in fluid communication with the collection cavity 14. This means that the opening 32 connects the collection cavity 14 to the airflow flowing along the flow surface 11.

[0040] exist Figure 1 In the provided example, the flow body 10 further includes a plurality of suction openings 20 in fluid communication with the manifold 14. The suction openings 20 are adapted to induce suction when they are exposed to the airflow during flight. This suction induces an airflow through the opening 32, the manifold 14, and the suction openings 20. However, the flow body 10 may also include only a single suction opening 20.

[0041] Suction can be generated at the suction openings 20 because these suction openings are arranged in the region of airflow on the flow surface 11, where the airflow has a lower pressure than in the manifold 14 due to the lower pressure in the manifold 20. In an example, the suction openings 20 may be Venturi nozzles driven by airflow during flight.

[0042] This airflow reduces the pressure at the perforated region, thereby drawing the airflow flowing along the flow surface 11 in the perforated region toward the flow surface 11. This drawing of the airflow toward the flow surface 11 maintains a boundary layer thickness suitable for laminar flow conditions.

[0043] Suction openings 20 are arranged in regions 24 of turbulent airflow. During flight, those regions 24 of turbulent airflow are generated by flow surfaces 11. Flow surfaces 11 may include turbulence-generating structures 22, which may be, for example, rivets or the edges of the outer skin of the aircraft wing 12.

[0044] The manifold 14 can be divided into multiple manifold sections 16. The wall 26 can separate the manifold sections 16 from each other. The separation through the wall 26 can be provided in an airtight manner (i.e., there is no airflow between the manifold sections 16 in this case).

[0045] Each manifold section 16 is in fluid communication with the portion separated from the perforated region and with its opening 32.

[0046] Furthermore, each manifold section 16 is in fluid communication with a separate suction opening 20. This means that the suction opening 20 can be connected to only one manifold section 16 (i.e., in a one-to-one manner). Therefore, airflow through the opening 32 into the manifold section 16 flows through the manifold section 16 and the separate suction opening 20 in fluid communication with the manifold section 16.

[0047] In the case of providing multiple suction openings 20, if one of the multiple suction openings 20 fails, only a portion of the manifold 14 will stop providing laminar flow control for the airflow flowing along the flow surface 11.

[0048] Figure 2 It shows Figure 1 Details of the fluid body 10. Figure 1 In the middle, this detail is marked by a dashed circle.

[0049] Figure 2A perforated region with openings 32 at the leading edge 18 is shown, these openings being in fluid communication with one of a plurality of manifold sections 16. A suction opening 20, in fluid communication with the manifold section 16, can be arranged on a suction tube 28. The suction tube 28 includes a first end 27 and a second end 29. The suction opening 20 is arranged on the second end 29. The first end 27 is in fluid communication with the manifold section 16, i.e., with the manifold 14. Therefore, air can flow from the manifold section 16 through the first end 27 to the second end 29 and through the suction opening 20.

[0050] The wall 26 can be secured to the flow surface 11, for example, by rivets. Those rivets can be turbulence-generating structures 22 of the region 24 that generates turbulent airflow during flight. The region 24 of turbulent airflow can be conical, with the tip of the cone pointing upstream of the airflow flowing along the flow surface 11.

[0051] The suction pipe 28 and suction opening 20 are arranged in the region 24 of the turbulent airflow. This means that any turbulence generated by the suction pipe 28 or suction opening 20 will appear in the region 24 of the turbulent airflow caused by the turbulence generating structure 22. Therefore, the turbulence generated by the suction pipe 28 or suction opening 20 will not add any additional region of turbulent airflow to the airflow flowing along the flow surface 11.

[0052] Because the flow body 10 may include multiple walls 26 for separating multiple flow chamber sections 16 in the flow chamber 14, multiple turbulence generating structures 22 may exist on the flow surface 11. This means that multiple regions 24 of turbulent airflow that are spaced apart from each other may exist in the airflow on the flow surface 11.

[0053] If there are more than one turbulent airflow region 24 in the airflow flowing along the flow surface 11, the suction opening 20 can be arranged in the separated turbulent airflow regions 24. Thus, the suction openings 20 can be arranged spaced apart from each other. However, if the turbulent airflow region 24 covers an extended area on the flow surface 11, the suction openings 20 can also be arranged spaced apart from each other in that turbulent airflow region 24.

[0054] Each manifold section 16 may include a region 24 of turbulent airflow associated with it on a one-to-one basis. This means that a manifold section 16 includes its associated region 24 of turbulent airflow. Any suction pipe 28 or suction opening 20 associated with the manifold section 16 may be arranged in that associated region 24 of turbulent airflow.

[0055] exist Figure 1The cross-sections of the suction tube 28 at the different locations 42, 44, and 46 shown can be adapted to the local pressure at those locations. For example, if it is assumed that there is a higher pressure at location 42 than at locations 44 and / or 46, the cross-section of the suction tube at location 42 can be smaller than the cross-section of the suction tube at locations 44 and / or 46. This is because the suction force provided by the suction opening 20 at location 42 will be higher than the suction force provided by the suction opening 20 at locations 44 and 46.

[0056] By taking into account the local pressure at the location of the suction opening 20 during flight, the cross-section of the suction tube 28 can be adapted to that local pressure. This can result in an optimized cross-section of the suction tube 28 that causes an optimized airflow through the opening 32 to provide the suction required to laminate the airflow in the perforated region at those openings 32.

[0057] Figure 3 It shows Figure 1 The vertical cross-section of the flow body 10, which may be an aircraft wing 12, is shown. The cross-section of the flow body 10 shows a flow surface 11 and a flow collection cavity section 16 of a flow collection cavity 14 within the flow body 10. The flow collection cavity 14 is defined by a front spar 34 and the skin of the aircraft wing including the flow surface 11. A portion of the flow surface 11 includes at least one perforated area comprising a plurality of openings 32 extending through the flow surface 11.

[0058] The suction tube 28 is connected to the suction opening 22 of the manifold section 16. The suction tube 28 is arranged on the flow surface 11 such that the suction tube 28 protrudes from the flow surface 11.

[0059] Figure 3 Arrows are shown indicating the airflow through the opening 32, the manifold section 16, the suction tube 28, and the suction opening 20 in the perforated area.

[0060] Furthermore, the manifold section 16 includes a lift enhancement device 30, which may be, for example, a Kruger lift enhancement device. The lift enhancement device 30 can be pivoted to open the manifold section 16. In this case, the opening provided by pivoting the lift enhancement device 30 can induce additional airflow into the manifold section 16.

[0061] Figure 4 Another example of the flow body 10 is shown.

[0062] The flow body 10 may be a vertical tail 36. The vertical tail may include a flow collection cavity 14 at the leading edge 18.

[0063] In another example, the flow body 10 may be a horizontal tail 38, wherein the flow collection cavity 14 may be arranged at the leading edge 18 of the horizontal tail 38.

[0064] Figure 5 An aircraft 40 comprising multiple flow bodies 10 is shown. The flow bodies 10 may be wings 12, winglets 37, vertical tail 36, and / or horizontal tail 38. Furthermore, the flow bodies 10 may be any additional element of the aircraft 40 requiring laminar flow control of airflow.

Claims

1. A flow body (10) for an aircraft, the flow body comprising: A flow surface (11) that is exposed to airflow during flight of the aircraft, and the flow surface (11) generates at least one region (24) of turbulent airflow during flight of the aircraft. At least one perforated region, the at least one perforated region comprising a plurality of openings (32) extending through the flow surface (11). A flow collector (14), which is positioned inside the flow surface (11) and in fluid communication with the opening (32), and At least one suction tube (28) having a first end (27) and a second end (29), the first end (27) being in fluid communication with the collection cavity (14), and the second end (29) including a suction opening (20) and arranged in the region (24) of the at least one turbulent airflow. The suction opening (20) is adapted to generate a suction force in at least one suction tube (28) when the flow surface (11) is exposed to airflow during flight, thereby causing an airflow through the plurality of openings (32). The fluid body is an airfoil, which includes one or more of the following: an aircraft wing (12), a winglet (37), a vertical tail (36), or a horizontal tail (38). The airfoil is an aircraft wing including a lift enhancement device (30), which is configured to be arranged in the air intake cavity (14), and The lift enhancement device is a Kruger lift enhancement device.

2. The flow body according to claim 1, wherein, The flow body (10) includes a plurality of suction tubes (28).

3. The flow body according to claim 2, wherein, The flow surface (11) generates multiple regions (24) of turbulent airflow that are spaced apart from each other during the flight of the aircraft, wherein the multiple suction tubes (28) are arranged separately in the multiple regions (24) of turbulent airflow.

4. The flow body according to claim 3, wherein, The flow collection cavity (14) includes a plurality of flow collection cavity sections (16), wherein each of the plurality of flow collection cavity sections (16) is arranged on a separated portion of the at least one perforated region.

5. The flow body according to claim 4, wherein, The plurality of suction tubes (28) and the plurality of collection chamber sections (16) are associated with each other in a one-to-one ratio.

6. The flow body according to claim 4 or 5, wherein, The collection chamber section (16) is separated by a wall (26).

7. The flow body according to claim 6, wherein, The wall (26) provides an airtight seal between the manifold sections (16).

8. The flow body according to any one of claims 1 to 5, 7, wherein, Each of the at least one suction tube (28) includes a cross section adapted to the pressure value at the location of the suction opening (20) in the region (24) of the turbulent airflow.

9. The flow body according to any one of claims 1 to 5, 7, wherein, The flow surface (11) includes a turbulence generating structure (22) that generates the at least one region (24) of turbulent airflow.

10. The flow body according to any one of claims 1 to 5, 7, wherein, The flow body (10) includes a leading edge (18) facing the airflow during flight, wherein the at least one perforated region is arranged at the leading edge (18).

11. An aircraft (40) comprising at least one mobile body (10) according to any one of claims 1 to 10.

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