DE102022115054A1 - wing body - Google Patents

Abstract

The invention relates to an aerodynamically flowable wing body with an internal support structure and an outer skin covering the internal support structure, the outer skin perforated in this area being arranged at a distance from the support structure at least in sections by means of spacers in order to form an internal cavity between the outer skin and the support structure, which extends over the Perforation of the outer skin is in communication with an ambient medium, characterized in that an inductive de-icing system is provided in the internal cavity, which has a plurality of induction coils arranged next to one another, which generate an alternating magnetic field in response to an alternating current supplied to the induction coils, which is used for inductive Heating of the outer skin interacts accordingly, with at least one induction coil having a flux concentrator provided in the middle of the coil.

Description

The invention relates to an aerodynamically flowable wing body, in particular for a flying object, with an internal support structure and an outer skin covering the internal support structure, the outer skin perforated in this area being arranged at a distance from the support structure at least in sections by means of spacers in order to form an internal cavity between the outer skin and the support structure , which communicates with an environmental medium via the perforation of the outer skin.

Airplanes have aerodynamic surfaces over which the air flowing around them flows at a speed and thereby generates a lifting force that allows the aircraft to fly within the atmospheric air masses. However, depending on the flight situation, such aerodynamic surfaces can be susceptible to icing, whereby a layer of ice (partial or complete) forms on the outer flow surface around which the surrounding air masses flow, which changes the aerodynamic properties of the aerodynamic surface and thus has a negative effect on the overall flight condition can. Such icing can quickly lead to critical situations, particularly during take-off and landing. It is therefore necessary, in particular, to de-ice the aerodynamic surfaces, such as wings, in the event of icing or to prevent further icing, for example during flight operations.

It is known from practice that if the wings are icing, which has already occurred on the ground and it has been determined that the aircraft is de-iced using a liquid before take-off in order to remove the layer of ice that has formed on the wing. However, this process leads to a delay in handling the aircraft at the airport and thus higher costs. In addition, icing on the wings that develops during flight operations cannot be treated in this way.

It is also known to provide a thermal de-icing system in the wings of the aircraft, preferably in the area of the wing leading edge, which is known to be very susceptible to icing due to its exposed position, which generates heat input into the outer flow surface in order to close the ice layer melt to avoid further freezing of the wings.

For example, electrical conductors can be embedded in the outer skin, which can be subjected to a current flow in order to induce heat input due to the electrical resistance of the electrical conductors. However, due to the size of the wings and the high sub-zero temperatures during flight operations, the ladders have to be laid very closely, which leads to higher production costs and also causes a significant amount of weight to be added to the aircraft.

Such a de-icing system must therefore be as efficient as possible, i.e. H. it must have the lowest possible mass and the lowest possible energy requirement. Furthermore, the system must be able to be integrated into a wing body, especially if the wing body is constructed in multiple layers and is intended to be designed for laminar operation for boundary layer suction.

In the US 2014/0319278 A1 A de-icing system is described that consists of a plurality of inductive heating elements that are designed in the form of a coil. If the inductive heating elements are fed with an alternating voltage, the current flow caused by the alternating voltage leads to an alternating electromagnetic field, which causes eddy currents in the outer skin, which, due to the electrical resistance of the outer skin, lead to heating and thus to thermal energy input.

The disadvantage here is that in the US 2014/0319278 A1 The proposed de-icing system does not achieve homogeneous heating, which means that the energy input must be increased for complete de-icing. The proposed arrangement leads to many small central areas in which the magnetic field or the magnetic flux changes direction or forms a pole. Especially with thin materials and actually poor efficiency (very high penetration depth), the efficiency decreases further as the angle of the magnetic flux to the ceiling of the material increases. As a result, cold spots form at the poles, where the conductor of a coil is inserted, but no significant heat coupling occurs. These cold spots are typically also found on the edges of this coil.

Against this background, it is the object of the present invention to provide an improved de-icing system for wing bodies.

The object is achieved according to the invention with the wing body according to claim 1. Advantageous embodiments of the invention can be found in the corresponding subclaims.

According to claim 1, an aerodynamically flowable wing body is proposed, which has a internal support structure and an outer skin covering the internal support structure. At least in sections, the outer skin is spaced from the support structure, whereby a cavity is formed between the outer skin of the support structure. The outer skin is attached to the support structure using spacers to form the cavity.

And a cavity in the sense of the present invention is also understood if it is composed of a plurality of partial cavities.

The outer skin has a perforation in the area of the underlying cavity, whereby the cavity is in communication with an ambient medium, for example the air flowing around it. With the help of a suction device, a negative pressure can be generated in the cavity, whereby the boundary layer on the outer flow surface of the outer skin is sucked into the cavity. This allows the longest possible flow around the laminar to be achieved. The transition from laminar boundary layer flow to turbulent boundary layer flow can thus be further delayed.

Due to the laminar nature of the boundary layer, the air resistance of the wing body can be reduced, which can save fuel costs.

According to the invention, it is now provided that an inductive de-icing system is provided in the internal cavity, which has a plurality of induction coils arranged next to one another, which generate an alternating magnetic field in response to an alternating current supplied to the induction coils, which interacts accordingly to inductively heat the outer skin, whereby at least one induction coil has a flux concentrator provided in the middle of the coil.

The induction coils can in particular be flat induction coils in which the surface area is many times larger than the thickness of the induction coils. In particular, it can be provided that the induction coils have a length in the surface that is many times larger than the width in the surface.

By using a flux concentrator (also called a flux guide) in the middle of the coil, the negative effects of pole formation when using a large number of induction coils can be avoided, allowing the outer skin to be heated more homogeneously and therefore more efficiently.

The wing body is in particular a wing body for flying objects, such as wings, horizontal stabilizer, vertical stabilizer, rotor blades of wind turbines or rotor blades of helicopters. A wing body in the sense of the present invention is therefore a body that can be flowed around aerodynamically and which, when a fluid flows against it, generates a force of whatever kind due to the flow.

According to one embodiment, it is provided that at least some of the induction coils are arranged between two adjacent spacers, with the flux concentrator provided in the middle of the coil being arranged centrally between the adjacent spacers in at least one induction coil.

This design variant has the advantage that the induction coils can be removed and reinstalled very easily, which has a positive impact on maintenance costs. In addition, this embodiment variant is preferred if the spacers are made of a non-conductive and non-magnetic material.

The alternating electromagnetic field is radiated through the spacers and thus creates a very homogeneous temperature distribution.

According to one embodiment, it is provided that in at least some of the induction coils the spacers are located in the center of the coil, with the flux concentrator provided in the respective center of the coil being formed by the central spacer.

In this embodiment variant, part of an induction coil lies in a first partial cavity, while the other part of the induction coil lies in the adjacent second partial cavity, the two partial cavities being separated from one another by a spacer element and the flux concentrator provided for the induction coil passing through this spacer is formed. The spacer thus forms the magnetic core of the coil.

The material provided for the flow concentrator can be arranged on the spacer. However, it is also conceivable that the material for the flow concentrator is integrated in the spacer or that the spacer consists of such a flow concentrator material.

This embodiment variant is preferably used when the spacers consist of an electrically conductive and magnetic material in order to avoid unnecessary heating of the spacers.

According to one embodiment, it is provided that the induction coils are connected to a control device which is set up to control the supply of the alternating current to the individual induction coils, at least partially neighboring induction coils being controlled in the same phase.

The in-phase control can ensure that corresponding cold spots are avoided in the edge areas between adjacent induction coils, thereby achieving a particularly homogeneous temperature distribution on the outside of the outer skin. In-phase here means that the current flow in the adjacent conductors of the adjacent induction coils runs parallel.

According to one embodiment, it is provided that for at least some of the induction coils the coil density in an edge region and/or in a central region is higher than in an intermediate region lying between the edge region and the central region.

This makes it possible to mitigate the negative effects of pole formation and to achieve the most homogeneous possible temperature distribution.

According to one embodiment, it is provided that in order to increase the coil density, the respective induction coil is wound in multiple layers in the edge region and/or in the central region.

According to one embodiment, it is provided that the induction coils arranged in the cavity are arranged on an inside of the outer skin or on an outside of the support structure.

According to one embodiment, it is provided that the support structure of the wing body is formed from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material.

According to one embodiment it is provided that the outer skin has, contains or consists of titanium.

Also included in the present invention is a flying object or a wind turbine with a wing body, as described above.

• 1 schematische Darstellung des erfindungsgemäßen Flügelkörpers;
• 2 schematische Querschnittdarstellung;
• 3 schematische Draufsicht in einer ersten Ausführungsform;
• 4 schematische Draufsicht in einer zweiten Ausführungsform;
• 5 schematische Querschnittdarstellung in einer weiteren Ausführungsform.

The invention is explained in more detail by way of example using the attached figures. Show it:

• 1 schematic representation of the wing body according to the invention;
• 2 schematic cross-sectional representation;
• 3 schematic top view in a first embodiment;
• 4 schematic top view in a second embodiment;
• 5 schematic cross-sectional representation in a further embodiment.

1 shows schematically the structure of the wing body 10 according to the invention in the form of a wing leading edge. The wing body 10 has an internal support structure 11 and an outer skin 12 covering this internal support structure 11. The outer skin 12 is arranged at a distance from the inner support structure 11 in the area of the wing leading edge and has spacers 13 for this purpose, via which the outer skin 12 is arranged on the inner support structure 11 to form a cavity 14.

The cavity 14 is divided into individual partial cavities 14a, which are limited in particular by the spacers 13 and can extend, among other things, over the entire span of the wing body 10.

The outer skin 12 has a perforation with which the external environment of the wing body 10 is in communication with the cavity 14. Using a suction device (not shown), a negative pressure can now be generated in the cavity 14, as a result of which the boundary layer that forms on the outer side of the outer skin 12 is sucked off as the flow flows against the wing body 10. In this way, a laminar boundary layer flow can be positively influenced and a transition to a turbulent boundary layer flow in the area of the leading edge of the wing can be avoided or reduced.

According to the invention, induction coils 15 of a de-icing system are now arranged in the cavity 14, which in the exemplary embodiment of 1 are arranged in the area of the inside of the outer skin 12.

If the induction coils 15 are fed with an alternating electrical voltage, a current flow occurs in the coils 15, so that an alternating electromagnetic field is generated. This alternating electromagnetic field couples in the material of the outer skin 12 and generates eddy currents here, which are converted into thermal energy due to the electrical resistance of the outer skin 12. A heating of the outer skin 12 is the result and leads to de-icing if a layer of ice is present, or follows icing.

2 shows a cross section through a partial cavity 14a in the 1 designated cavity 14, which is delimited by two spacers 13. The outer skin 12 is attached to the spacers 13, so that the outer skin 12 is attached to the support structure (in 2 not shown) to attach to the wing body.

Schematically, in a simplified representation, there is an induction coil 15 in the partial cavity 14a, which has a coil center 16. According to the invention, in this coil center 16, which forms a magnetic pole when the induction coil 15 is energized, there is a flux concentrator 17, which can be, for example, a ferrite, soft-magnetic composite or an iron sheet.

In the illustration below 2 The calculated heating power of the outer skin 12 is shown, whereby in the area of the coil center 16 it can be seen that the heating power increases significantly very quickly. Without the flow concentrator 17, such an increase would not be expected.

This gives the invention the possibility of achieving a homogeneous temperature distribution of the outer skin 12, whereby cold spots in the area of the poles (middle of the coil) are avoided.

3 shows an exemplary embodiment in which an induction coil 15 with a flux concentrator 17 in the middle of the coil 16 is provided in a first partial cavity 14a and in a second partial cavity 14b, which is adjacent to the first partial cavity 14a. The partial cavities are limited by the spacers 13 in the flow direction and are not limited in the span direction.

The induction coils 15 are significantly longer in the span direction than in the flow direction, where they are limited by the spacers 13. The adjacent induction coils 15 are designed so that they work in phase, i.e. H. the current flow direction 18 is identical in the adjacent conductors of the adjacent induction coils 15, which is indicated by the two arrows.

The in-phase current flow ensures that the probability of cold spots is reduced in the edge areas between the two induction coils 15, which are separated from one another by the central spacer 13, and thus a largely homogeneous temperature distribution is achieved.

4 shows an exemplary embodiment in which the spacers 13 run through the middle of the coil 16 and thereby form the respective flow concentrator 17. The partial cavity 14a thus has a first part of the left induction coil 15a and a second part of the right induction coil 15b.

The flow concentrator 17 in the area of the spacers 13 ensures that cold spots in the area of the spacers 13 are avoided. The in-phase current flow 18 also ensures that the polemics resulting from the polemics are also reduced in the middle of the partial cavity 14a. Refrigerate

5 finally shows, in a highly simplified representation, a cross section through half of a partial cavity, in which the flow concentrator 17 and half of the auction school 15 can be seen on the left side. The individual conductors 19 of the induction coil 15 can be seen in the cross-sectional view.

In the area of the flux concentrator 17 it is now provided that the coil 15 has an additional winding 19a. The pole formation in the middle of the induction coil 15 leads to a decreasing heat output on the outer skin 12, which is compensated for by an additional winding 19a so that the heating output in the area of the center of the coil is increased. The cold spot that forms at the center of the coil can be minimized in this way. The result is a more homogeneous temperature distribution.

Reference symbol list

10

wing body

11

Support structure

12

outer skin

13

Spacers

14

cavity

14a, 14b

Partial cavity

15

induction coil

16

Coil center

17

flow concentrator

18

Current flow direction

19

Coil conductor

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2014/0319278 A1 [0007, 0008]

Claims (10)

Aerodynamically flowable wing body (10) with an internal support structure (11) and an outer skin (12) covering the internal support structure (11), the outer skin (12), which is perforated in this area, being separated from the support structure (11) at least in sections by means of spacers (13). is arranged at a distance in order to form an internal cavity (14) between the outer skin (12) and the support structure (11), which is in communication with an ambient medium via the perforation of the outer skin (12), characterized in that in the internal cavity (14 ) an inductive de-icing system is provided which has a plurality of induction coils (15) arranged next to one another, which generate an alternating magnetic field in response to an alternating current supplied to the induction coils (15), which interacts accordingly to inductively heat the outer skin (12), whereby at least one induction coil (15) has a flux concentrator (17) provided in the middle (16) of the coil. Wing body (10). Claim 1 , characterized in that at least some of the induction coils (15) are arranged between two adjacent spacers (13), with at least one induction coil (15) having the flux concentrator (17) provided in the middle of the coil (16) centrally between the adjacent spacers (13 ) is arranged. Wing body (10). Claim 1 or 2 , characterized in that in at least some of the induction coils (15), the spacers (13) are located in the center of the coil (16), the flux concentrator (17) provided in the respective center of the coil (16) being formed by the central spacer (13). . Wing body (10) according to one of the preceding claims, characterized in that the induction coils (15) are connected to a control device which is set up to control the supply of the alternating current to the individual induction coils (15), at least partially adjacent induction coils (15) be controlled in phase. Wing body (10) according to one of the preceding claims, characterized in that in at least some of the induction coils (15), the coil density in an edge region and/or in a central region is higher than in an intermediate region lying between the edge region and the central region. Wing body (10). Claim 5 , characterized in that to increase the coil density, the respective induction coil (15) is wound in multiple layers in the edge area and/or in the middle area. Wing body (10) according to one of the preceding claims, characterized in that the induction coils (15) arranged in the cavity (14) are arranged on an inside of the outer skin (12) or on an outside of the support structure (11). Wing body (10) according to one of the preceding claims, characterized in that the support structure (11) of the wing body (10) is formed from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material. Wing body (10) according to one of the preceding claims, characterized in that the outer skin (12) has, contains or consists of titanium. Flying object or wind turbine with a wing body (10) according to one of the preceding claims.

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