DE102010014641A1 - Wall section for structure component for flow components of airplanes, has external cover, which is formed permeable for air flow, where internal cover is arranged with openings - Google Patents

Abstract

The wall section has an external cover (40), which is formed permeable for air flow. An internal cover is arranged with openings (34). A porous metal foam core (30) is arranged between the two covers. The external cover is supported against the internal cover. Independent claims are also included for the following: (1) a structure component with two side wall sections; and (2) a method for manufacturing a structure component.

Description

The invention relates to a wall section for a structural component for use for flow components of aircraft and to the structural component itself and to a method for the production thereof. Furthermore, the invention relates to a flow component for an aircraft with a structural component.

From the aerodynamics it is known that a laminar flow around carrying and guiding surfaces provides the highest possible lift with at the same time least resistance to the direction of flow. However, due to the given profile shape, it is often not possible to ensure such a laminar flow for all incident flow conditions occurring. Even with constant inflow conditions, the flow can become detached from discontinuities of the profile and become turbulent, resulting in reduced buoyancy and increased profile resistance.

As is further known from the field of aerodynamics, continuous aspiration of the turbulent layer can achieve a substantial laminarization of the flow. Since under cruise conditions a reduction in resistance at the same time also leads to a significant fuel savings, can be achieved by a Strömungslaminarisierung considerable economic benefits. Therefore, attempts have already been made to arrive by the attachment of suction in the wing to such a flow laminarization. In this context, it is an already known measure to provide extending on the surface of an airfoil in the spanwise slot-shaped suction or micro perforation. If such hollow components are provided by a designated as superplastic forming process in which they are expanded by means of internal pressure in a negative mold, the perforation of the surface aggregation must be made after the forming process, otherwise not required for the forming process internal pressure in the component can be produced. However, such subsequent perforation is associated with a considerable work and expense.

A disadvantage of the known cavity profiles is further that holes in the upper cover plate are necessary, which are designed as a perforation and the suction of air for Strömungslamaminarisierung serve. Through this perforation with a bore size of 30 to 100 microns, air is sucked out and the formation of turbulent flow is thus suppressed. However, the production of the perforation is very expensive, especially when relatively large amounts of air and / or relatively large areas for the Strömungslaminarisierung come into question. The perforation is made in known methods in the upper cover plate by means of micro perforation, for example by laser technology. Depending on the technology and the perforation quality required, perforation frequencies of 100 to 300 Hz are possible. If one presupposes ideal flow laminarization in the case of a wing, a tail unit, an engine nacelle or a flap of a commercial aircraft as the basis, it is usual for approx. 4 million holes per m ^{2 to be} necessary. This results in medium quality for a production time of 4.45 hours for 4 million holes, ie of about 4½ hours per square meter. In order to produce the necessary perforation for vertical and vertical stabilizer of a commercial aircraft with 5 to 10 m ² are therefore more than two days necessary.

Another disadvantage with the use of known methods for producing the perforation are resulting burrs at the holes and / or surface impairments by the laser technology. At such surface impairments or burrs there is a risk of air turbulence and thus a negative influence on the flow. The flow becomes more turbulent again due to the burrs or surface impairments. The production technology would thus counteract the actual goal of Strömungslaminarisierung again and this at least partially cancel. If you do not want to take this disadvantage into account, so must connect to the production of perforation another, very complex manufacturing step of deburring, for example by chemical etching.

The object of the present invention is to solve the above-described disadvantages of known methods. In particular, it is an object of the present invention to provide a wall section and a structural component, which can be made simpler, faster and thus more cost-effective.

This object is achieved by a wall section having the features of independent claim 1 and by a structural component having the features of independent claim 7. Further objects of the present invention are a method having the features of independent claim 14 and a flow component having the features of the independent claim 16th

According to the invention, there is provided a wall section or paneling section for use with an aerodynamic body or flow component of an aircraft comprising an upper or outer cover plate or upper cover shell which is at least partially permeable to air flow and at least one inner cover plate or lower cover shell disposed therein Has openings. The permeability of the upper cover plate can advantageously by a Training be achieved at least partially as air permeable metal mesh assembly. Further, a porous metal foam core is provided, which is arranged between the two cover plates and is permeable to air flow and the outer cover plate is supported against the inner cover plate. The metal foam core can be connected in particular flat with the upper or lower cover plate. In this case, in the context of the present invention, the porous metal foam core can also extend at least partially onto the upper cover plate, thus at least partially forming it. A separate layer of a porous metal foam can also be used to form the permeable upper cover plate. A wall section according to the invention thus differs from the known wall sections in particular by the use of a metal mesh arrangement which is permeable to air and at least partially forms the upper cover sheet. This metal mesh arrangement may be multi-layered or consist of a single mesh layer. Under metal braid, or metal braid arrangement is to understand any form of individual substantially strand-shaped metal elements, for example metal wires, which are intertwined with each other. Different braiding methods can be used. Crucial for the choice of braiding method and the type of metal elements is for the metal braid arrangement that it is permeable to air flow and meets the structural requirements in terms of their mechanical strength.

This permeability of the metal braid assembly does not allow fabrication of the wall portion with an alternative method of creating a perforation, but already through the inventive use of the metal braid assembly. In this way, the additional step of perforating by laser drilling can be completely eliminated, so that not only a time reduction of this process step is possible, but this step and the time required for it completely eliminated. Thus, compared to the calculation of the manufacturing time in the introduction of this specification, the manufacturing process of the wall portion when used for flow component of a commercial aircraft, such as wings, tail, engine nacelle or butterfly valve significantly accelerated. This acceleration of production leads to a reduction in the manufacturing costs of the wall section.

Further eliminates any tolerance problem with respect to the perforation by the metal mesh assembly. Since no individual holes are made, no such must be checked for their tolerance accuracy. In addition, the use of a metal mesh arrangement according to the invention can enable a relatively free deformation of the hollow chamber profile. In contrast to cover plates with individual holes, which change during the forming of the hollow chamber profile, in particular during a forming process, the entire permeability of the metal mesh arrangement remains relatively unaffected by a forming process. This independence relates in particular to the permeability of the metal mesh arrangement with respect to the air flow. This is also crucial because sufficient airflow must pass through the top cover plate for successful flow laminarization.

By using the metal mesh arrangement for the structural component according to the invention, it is furthermore possible to achieve an even significantly smaller porosity, which corresponds to a significantly larger number of holes in the upper cover sheet, for example by means of even finer meshworks the manufacturing costs increased significantly. By using a metal mesh arrangement according to the invention for the wall section, the disadvantages mentioned are eliminated.

According to the invention, the metal mesh arrangement is combined with a porous metal foam core. This metal foam core takes over, inter alia, the task of supporting the cover plates against each other. In other words, the porous metal foam core serves for the mechanical stabilization of the wall section. It replaces otherwise usual structural profiles, such as honeycomb structures or truss structures. In its place, the porous metal foam core provides a full-surface support of the cover sheets against each other. In this way a constant over the surface of the cover plates away support just this cover plates is achieved. By increasing the force transmission surface for supporting the cover plates against each other, the force to be transmitted in the individual material regions of the porous metal foam core is reduced. In other words, the loads to be supported are distributed over a larger area than in the case of bars, truss structures or honeycomb structures. The resulting decrease in material load contributes to the safety of the component and, above all, to its longevity.

It is essential for the functionality of the present invention that it is a porous metal foam core. The term "porous" is understood to mean that the porous metal foam core is permeable to air flow. So he has a pore structure which is permeable to air flow. In this case, the pores of the porous metal foam core are connected to each other, so that, for example, a sponge-like structure can form the porous metal foam core. Here, the permeability of the porous metal foam core given in all three space dimensions. The air flow can therefore move substantially freely within the porous metal foam core. The freedom of movement of the air flow is not limited in space, but only by the resulting pressure loss in the porous metal foam core. From this it can be deduced that, depending on the thickness of the porous metal foam core, that is, depending on the distance of the two cover plates from each other, different pore sizes may be useful. In particular with larger thicknesses of the porous metal foam core, it should be noted that the pressure loss of the air flow as it flows through the porous metal foam core does not hinder or even prevent this air flow in the thickness direction between the two cover plates.

The porous metal foam core may be made of, for example, nickel-iron base. However, other, in particular corrosion-resistant materials, such as titanium or titanium alloys in the context of the present invention are conceivable. The pores can be produced both by a foaming process, that is building up, and by connecting, for example, by a sintering process. In particular, in the use of sintering processes for the production of the porous metal foam core, it may be useful to use this sintering process for the connection between the porous metal foam core and the cover plates. In other words, in such a variant, the porous metal foam core is as it were sintered to the cover plates. A full-surface connection between the porous metal foam and the respective cover plates may be advantageous, in particular if not only compressive forces but also tensile and / or shear forces are to be transmitted between the cover plates. This full-surface connection or even part-surface connections can be produced, for example, both by sintering, as well as by diffusion welding.

In areas of application in which solid or liquid soils are to be expected, it may be advantageous if the pore size, in particular the average pore size or the maximum pore size, of the porous metal foam core is greater than the pore size, in particular the average pore size or the maximum pore size, the metal mesh arrangement. In this way it is prevented that contaminants in the inaccessible from the outside of the inner wall portion, ie in the porous metal foam core, can get.

In the case of a wall section according to the invention, it may be advantageous if recesses are provided in the porous metal foam core which form passages between the porous metal foam core and the openings in the inner cover plate. In other words, these recesses increase the delivery surface of the porous metal foam core for air flow to the openings in the inner cover plate. While in direct contact of the porous metal foam core with the inner cover plate, the air flow discharge section from the porous metal foam core is identical to the cross section of the openings in the inner cover plate, by providing the recesses, the air flow discharge section can be enlarged from the porous metal foam core. In particular, this is in the range of 1.5 to 5 times the opening cross section of the openings in the inner cover plate.

Increasing the delivery cross section from the porous metal foam core has, inter alia, the advantage that the pressure loss, which virtually counteracts the air flow when leaving the metal foam core, becomes smaller. The air flow can escape from the porous metal foam core against resistance and leave the wall section via the openings in the inner cover plate.

It is irrelevant in a first step, which form the recesses. It is crucial that the discharge cross-section for air flow from the porous metal foam core is increased by the inventive design of the recesses in the porous metal foam core in such a way that passages between the porous metal foam core and the openings are formed in the inner cover plate. It is also irrelevant whether the recesses formed by the removal of material, or are already taken into account in the manufacture of the porous metal foam core.

It may be advantageous if the recesses at least partially have a spherical shape. In other words, the recesses can be hemispherical or partially spherical shells, which can be designed, for example, in a simple and cost-effective manner by means of a round milling head. The recesses may be designed such that each opening in the inner cover plate is associated with exactly one recess. However, it is also possible that the recesses are each provided for a plurality of openings in the inner cover plate.

Furthermore, it is possible that the recesses have at least partially a longitudinal extent and thus form elongate grooves in the porous metal foam core, which are arranged along the direction of the longitudinal extension of the grooves one behind the other and / or next to each other. The molding of such grooves by means of the recesses in the porous metal foam core serves to form channels or even network structures of the grooves, which still have a distribution of the air flow within the wall section, but already allow after exiting the porous metal foam core. The distribution within the wall section, but outside of the porous metal foam core has the advantage that at a relatively low pressure loss, a redistribution or compensation of the air flow can be made without attachments or external components on the inner cover plate are necessary.

Since in the regions of the porous metal foam core in which the recesses are located, the thickness of the porous metal foam core is smaller than the distance between the two cover plates, it may be useful for the recesses to support the porous metal foam core have at least one reinforcing element, which in Contact with the porous metal foam core is at least partially permeable to air flow. The reinforcing element, which is inserted for example in the form of a film or a shell or a sheet in the recess, thus serves to compensate for the weakening in mechanical terms at this point. It is important that this reinforcing element is also permeable to air flow, otherwise the advantage of the increased discharge cross-section in the porous metal foam core would have disappeared again. The permeability can be made, for example, by the use of porous materials for the reinforcing element or by providing holes therein.

A further subject of the present invention is a structural component for use in aircraft flow components. Such a structural component has at least two side wall sections, each comprising at least one wall section according to the invention and at least one nose section, which has an outer nose plate permeable to air flow and is arranged between the two side wall sections and connected thereto. Furthermore, at least one central air duct is provided, which is in fluid communication with the permeable metal mesh arrangement via the openings and the metal foam core for sucking air from the outside of the outer cover plate.

In this case, the individual sections, ie side wall sections and nose section can be manufactured separately, so that in principle a modular structure is possible. For example, the sidewall sections may be prefabricated individually with the metal braid assembly and / or the porous metal foam core, so that the tool sizes become smaller for the entire structural component. In particular, in cases where the sidewall portions are identical components, a single tool can be used to fabricate all the sidewall portions. This increases the efficiency of the entire production and thus reduces costs significantly.

To ensure that extracted in the structural component of the top of the outer cover plate, so from the top of the structural component, air can also be removed in the interior of the structural component, openings in the inner cover plate and an inventive porous metal foam between the cover plates are provided. The exact location of the openings in the inner cover plate depends on the desired arrangement of the central air duct. In any case, the openings are arranged, or configured such that the, for example, generated by a pump vacuum in the central ventilation duct via the openings in the hollow chamber profile can act on the metal mesh assembly and thus suction of air from the outside of the outer cover plate is made possible ,

In order to suppress a turbulent flow in the nose portion of the structural component, while the outer nose plate is also permeable to air flow, so that an influencing of the flow before the nose portion can take place. It is irrelevant in a first step in which way the permeability of the nose area is achieved. Thus, as will be described later, the use of the metal mesh arrangement and / or the porous metal foam core is also possible here. However, due to the relatively small area of the nose portion compared to the area of the side wall portions, more expensive methods, such as laser drilling, are conceivable for producing the permeability of the nose portion.

The central air duct is used to connect a compressor, a pump, or basically a device which is able to generate a negative pressure in this central air duct and to suck air. The term "fluid-communicating connection" is to be understood as meaning that the central air duct is connected to the metal mesh arrangement of the outer cover plate via the openings in the inner cover plate such that a negative pressure generated in the central air duct via the metal mesh arrangement and the porous metal foam core air from the Can suck off the top of the upper cover plate.

The combination of the porous metal foam core with the metal mesh arrangement brings about the same advantages for the structural component according to the invention as have already been explained for the wall section according to the invention.

Furthermore, in the context of the present invention, the side wall sections of the structural component and the at least one nose section can be components which are produced separately from each other and non-detachably connected to one another. In this way, the advantage is achieved that smaller and therefore more cost-effective tools can be used for the production of the structural component. In particular, the sidewall regions can be made more complex with respect to their structure as compared to otherwise customary manufacturing methods for all sections. In particular, an embodiment according to the invention of the side wall regions with a porous metal foam core is thus easier and more cost-effective.

The individual components, ie the separate side wall portions and the nose portion are connected to each other inextricably to create a mechanically stable structural component. This connection can be done for example by means of laser beam welding, soldering, gluing or riveting. As could be saved by the smaller tools for each section significantly in complexity in the manufacturing process, with regard to the connection of the individual sections, even more complex connection methods are economically feasible. Thus, despite the complexity reduction for a structural component according to the invention, a sufficient mechanical stability can be achieved in order to satisfy the structural requirements of the structural component.

One possibility for forming the central air duct is the provision of a channel plate which, together with the outer nose plate of the nose section, forms at least one line section of the central air channel. The central air duct comes in this way to lie directly behind the nose section. The further interior of the structural component, ie the area between the side wall sections, remains free of internals and can be used for other components or even functional elements. Another advantage, in addition to the space that can be achieved thereby, is achieved by a central air channel formed in this way, since in this way the pressure loss in the central air duct is reduced. In particular, the air volume, which is present, so to speak, as a dead space in the interior of the central air duct, is significantly smaller than if the entire area between the side wall sections is present as a dead space. Changes in the negative pressure, ie changes in the Absaugcharakteristik can be passed in this way much faster reaction to the surface of the upper cover plate. The entire system for influencing the flow through the structural component according to the invention thus becomes significantly more responsive.

Further, the channel plate of such an embodiment may also be used to enhance or complete the connection of the nose portion with the side wall portions. Thus, the mechanical stability of the entire structural component is improved over the channel plate, whereby the outer nose plate can be formed in structural terms easier. The connection of the channel plate with the respective sections is carried out, for example, laser beam welding, soldering, gluing, riveting or other unsolvable connection methods.

Alternatively, a channel plate may also be provided which, together with the outer nose plate of the nose section and the inner cover plates of the side wall sections, forms at least one line section of the central air channel. In other words, the central air passage is completely formed by the inner space between the side wall portions and the nose portion. In this case, the channel plate is preferably flexible, so for example formed as a membrane. In this way prevents bending moments in the channel plate can occur, which could lead to tearing of the channel plate. Due to the large cross section of this alternative embodiment, the further advantage is achieved that even large air flow rates can be easily promoted. In this embodiment of the present invention, the openings are provided in the inner cover sheets of the sidewall portions to establish a fluid communicating connection between the metal mesh assembly and the central air passage.

To make the entire construction of a structural component according to the invention even simpler and more compact, it may be advantageous if the outer nose plate of the nose portion at least partially also consists of a metal mesh arrangement which is permeable to air flow and between the outer nose plate and an inner nose plate also the porous metal foam core is provided. As a development of simple holes, which have for example been introduced into the nose section by means of laser beam welding, the use of a metal mesh arrangement and of the porous metal foam core also has the same advantages in the nose section as has already been described for the side wall sections. In particular, an efficient flow laminarization can be achieved in the flow-technically critical region of the nose section, on which a dynamic pressure usually prevails when used for flow components of an aircraft.

In this case, advantageously, the metal braid arrangements and / or the porous Metal foam cores of the nose portion and the side wall portions to be made integral. The integral design has the advantage that it is possible to dispense with connections, which usually entail fluidic disadvantages, between the outer cover plates and the outer nose plate. Also, other components of the nose portion, in particular, for example, an inner nose plate may also be integrally formed with the inner cover plates of the side wall portions. Such an integral embodiment can be produced, for example, by a manufacturing method in which, in a first step, a porous metal foam core obtains the desired curvature (s) of the structural component by forming and, in a second step, is arranged between the two already curved cover sheets. Subsequently, the three individual parts are joined together, for example by sintering or by diffusion welding.

Furthermore, it may be advantageous if the openings in the inner cover plates of the side wall sections have larger opening cross sections as the distance from the nose section increases. The openings in the inner cover plates of the side wall sections may also be referred to as diaphragms in their mode of action, the opening cross-section of which is responsible for the air passage rate of the respective diaphragm. When using the structural components according to the invention for flow components of aircraft profiles are usually used for the structural components, in which the flow pressure on the outside of the profile varies over the tread depth in the flow direction. In particular, the flow pressure on the outside of the profile at its counter to the flow direction furthest forward region, ie in the nose portion is greatest and decreases in the flow direction along the tread depth. Since the necessary negative pressure for sucking air from the surface of the upper cover sheets depends substantially on the flow pressure locally applied to this surface, the ideal negative pressure therefore also varies over the profile depth in the flow direction.

In the central air duct, however, a constant negative pressure is generated due to the technical simplicity. In particular, this negative pressure is constant over the tread depth in the flow direction. In order to adapt the constant negative pressure to the varying flow pressure, in this embodiment of the present invention, the opening cross sections of the openings in the inner cover plates of the side wall sections are increased over the depth of the profile in the flow direction. In other words, these openings are larger behind in the flow direction than the corresponding openings further forward. By this variation of the opening cross-sections, the effect of the constant negative pressure in the central air duct on the porous metal foam core and thus on the metal mesh assembly and the outside of the upper cover plate is varied. In particular, the actual course of the suction pressure on the outer side of the upper cover plates by the variation of the opening cross sections of the openings in the inner cover plates of the side wall sections is indirectly proportional to the profile of the flow pressure on the outer side of the outer cover plates of the side wall sections in the flow direction.

It may also be advantageous if in the fluid-communicating connection between the central air duct and the metal mesh arrangement at least one air collecting channel is provided, through which air from the metal mesh assembly and the porous metal foam core of the side wall portion of several openings in the inner cover plate of the side wall portion collected and conveyed to the air duct can. This collection takes place in particular via a plurality of openings in the inner cover plates of the side wall sections. In this way, the number of openings in the inner cover plates can be minimized compared to an embodiment with full-surface perforation of these inner cover plates. Due to the fact that each hole in the inner cover sheet from a mechanical point of view represents a weakening of the structural component, since each hole unfolds a notch effect with concomitant susceptibility to cracking due to the notch stress, the susceptibility of the structural component is further reduced by the use of an air collection channel. At the same time, the use of an air collecting channel makes it possible to extend the depth of the structural component in the direction of flow, since areas of the side wall sections lying further back relative to the direction of flow can be supplied with negative pressure via the air collecting channel (s), ie also in these areas an effective suction and thus An effective Strömungslamaminarisierung can take place.

In this case, the air collecting channel is designed as an annular channel which extends between openings in the inner cover plate of the side wall portion and the air channel. This extension thus runs essentially along the flow direction of the structural component. In this way, the air collecting channel additionally supports the mechanical stability of the structural component, since it acts as a reinforcing rib, so to speak. Depending on the required extraction volume, the flow cross-section of the air collection channels and the required mechanical stiffening by the air collection channels, distances in the spanwise direction of the structural component of 300 mm, 500 mm or up to 1000 mm may be expedient. The more mechanical stiffening you want, the better less are the distances of the air collecting ducts in the spanwise direction of the structural component to choose.

In order to optimally distribute the distribution of the negative pressure and thus also the extracted air to the central air duct, it may be useful if, in one embodiment of the present invention, the recesses in the porous metal foam core at least partially form side wall channels within the side wall section, which the fluidkommunizierende connection between form the metal mesh assembly and the air duct over the porous metal foam core. In this way, both in the spanwise direction, as well as in the flow direction of the structural component, an optimal distribution of the negative pressure for sucking the air from the outside of the upper cover plates can be achieved. In particular, it is ensured in this way that suction pressures achieved in the porous metal foam core in the spanwise direction of the structural component within the porous metal foam core can be propagated through the apertures in the inner cover plates of the sidewall sections which function as apertures. Also in this embodiment, the side wall channels act as air collecting channels, whereby the number of diaphragms can be reduced and thus the mechanical stability of the structural component is increased. Nevertheless, a uniform extraction of air via the metal mesh assembly and the porous metal foam core remains possible via the sidewall channels.

When using a structural component according to the invention for flow components of aircraft, it may be advantageous if the structural component is an aerodynamic body in which the nose portion is a portion of the aerodynamic body with congestion flow and the side wall portions portions of the aerodynamic body with a boundary layer to be formed. This is to be understood that on the outer side of the nose portion by the applied flow, a relatively high surface pressure prevails and at the side wall portions by the applied flow, a relatively low surface pressure. In other words, the nose portion points against the flow direction, while the side wall portions extend substantially along the flow direction. In particular, the structural component is used for areas of the tail, of butterfly valves or wings or the engine nacelles. Especially at these positions of an aircraft laminar flows for the flight stability of great advantage. In particular, on the tail unit and the wings, turbulent flows have a negative impact on safety and comfort in the respective flight situation. The use of a structural component according to the invention for these areas thus serves the safety and comfort as well as the economy of the aircraft by reducing fuel consumption.

• • Herstellen eines ersten Seitenwandabschnitts
• • Herstellen wenigstens eines zweiten Seitenwandabschnitts
• • Herstellen eines Nasenabschnitts
• • Anordnen des Nasenabschnitts zwischen den beiden Seitenwandabschnitten
• • Verbinden des Nasenabschnitts mit den beiden Seitenwandabschnitten

Another object of the present invention is a process for the preparation of an inventive with the steps:

• • Make a first sidewall section
• • producing at least one second sidewall section
• • Make a nose section
• • Arrange the nose section between the two sidewall sections
• • Connecting the nose section with the two side wall sections

An essential advantage of the method described above is the multi-part mode of production of the structural component. In this case, smaller molds can be used, which lowers the production costs. The quality of the structural component also increases, since problems in the deformation of the nose portion, in particular in the case of nose portions having a significantly greater curvature than the side portions, can be avoided by the separate production. Attention should be drawn in particular to the problem that can occur during deformation with strong curvatures in the nose section material compression and even drape on the surface of the material. This is avoided by the multi-part design of the sections.

• • Integrales Formen der äußeren Deckbleche und des äußeren Nasenbleches
• • Anordnen des porösen Metallschaumkerns an den äußeren Deckblechen und dem äußeren Nasenblech
• • Anordnen der inneren Deckbleche und des inneren Nasenblechs auf dem porösen Metallschaumkern

A method for the production according to the invention can be developed in that it comprises the following steps:

• Integral shaping of the outer cover plates and the outer nasal plate
• • Arranging the porous metal foam core on the outer cover plates and the outer nose plate
• • Arranging the inner cover plates and the inner nose plate on the porous metal foam core

In this way, more complex tools are necessary, but can be avoided by the integral molding material collisions and thus joints. In this way, the structural component is improved both mechanically and aerodynamically. In this case, so to speak, the two cover sheets, as well as the porous metal foam core prefabricated and then arranged one inside the other. This has the advantage that after the arrangement, in particular after the joining of the individual parts, no further forming step has to take place which could impair the material properties of the individual sections. The metal mesh can be placed loosely on top of each other and only during the connecting step via diffusion welding in itself get connected. Possible recesses in the porous metal foam core are advantageously produced even before the forming, that is to say the prefabrication, in the flat state of the porous metal foam core.

Another object of the present invention is a flow component of an aircraft comprising at least one structural component according to the invention. The advantages that can be achieved with this result from the comments on the structural component itself.

The present invention will be explained in more detail with reference to the accompanying drawing figures. The terms used "left", "right", "top", "bottom" refer to the drawings with an orientation with normal readable reference numerals. Show it:

1a in cross section an embodiment of the metal mesh arrangement,

1b in an isometric view the metal mesh arrangement,

2 in an isometric partial section an embodiment of a structural component according to the invention,

3 in cross section a further embodiment of a structural component according to the invention,

4 in cross section a section of an embodiment of a wall section with a porous metal foam core,

5 in cross section a section of a further embodiment of a wall section with a porous metal foam core,

6 In cross-section, a section of a further embodiment of a wall section with a porous metal foam core with reinforcing element,

7 in cross section a section of a further embodiment of a wall section with a porous metal foam core,

8th in the lower view, another embodiment of a wall section with a porous metal foam core.

In the 1a and 1b is a metal mesh arrangement 42 shown in more detail. In this case, any weaves, such as body tissue or armored tissue can be used. Such is in the embodiment according to 1a in cross-section to recognize that the individual metal wires 44 at different levels but not exclusively within these levels. Rather, the metal wires run 44 substantially wave-shaped and each offset at an angle of 90 ° to each other. This creates a mesh like it does for example in 1b is shown in isometric view. The single metal wires 44 extend one above the other and in alternation and intertwined in this way together to form a mechanically stable metal mesh arrangement 42 ,

The permeability of this metal braid assembly 42 This is due to the automatically occurring in the braid distances between the individual metal wires 44 and the resulting holes, or pores given. Depending on the tightness of the wickerwork and the distances between the individual metal wires 44 To each other, a higher or lower mechanical stability and also a higher or lower permeability can be adjusted in this way.

The metal mesh arrangement 42 is in it, so the individual metal wires 44 connected to each other via diffusion welding. Thus, individual layers of the metal mesh arrangement in itself, but also the individual layers of the metal mesh arrangement are interconnected via diffusion bonding. By using the diffusion welding method, connections between the metal wires become here 44 produced, which are on the one hand particularly durable, on the other hand also very simple, namely to be produced inexpensively. The diffusion welding process is in a in the 1a and 1b not shown tool 80 at about 1000 ° C and in the range between 10 to 85 bar, in particular between 20 and 60 bar, carried out over several hours, for example 3 hours away. There are basically a variety of braided structures conceivable. For example, it is possible that the individual metal wires 44 offset by about 90 ° to each other, as in the 1a and 1b is shown, and in each case alternately over each other and run through each other. Thus, a high mechanical stability is created over a plurality of contact points of the individual metal wires and at the same time through the spaces between the contact points and the metal wires 44 created sufficient openings, which lead to the desired permeability of the upper cover plate.

In 3 is an embodiment of a structural component according to the invention 10 shown in cross section. This is a flow component of an aircraft, for example on the tail unit. The structural component 10 has one nose section 80 and two sidewall sections 70 on which over the nose section 80 to the structural component 10 are connected. The two side wall sections 70 are with porous metal foam cores 30 equipped, as they have been explained in detail above the wall section according to the invention.

The nose section 80 of the structural component 10 has an outer nose plate 84 and an inner nose plate 82 on, which together with the porous metal foam core 30 in the nose section 80 both the mechanical stability of the nose portion 80 generated, as well as in 3 not shown openings 34 in the inner nose plate 82 the fluid communication with the central air duct 60 inside the structural component 10 generated. The openings 34 in the inner nose plate 82 are here, for example, by laser drilling or other drilling methods, preferably in the inner nose plate 82 made in its still flat state.

The central air duct 60 is between the sidewall sections 70 and the nose section 80 formed and thus takes practically the entire interior of the structural component 10 to complete. In 3 down is the air duct 60 through an air duct sheet 62 limited, which is crescent-shaped bent. When using the structural component 10 for example, for the tail of an aircraft is behind the duct plate 62 , So at the respective ends of the side wall sections 70 the jumper connection. Behind the channel plate 62 outside the air duct 60 also run electrical lines and / or hydraulic lines.

The central air duct 60 stands for the extraction of air from the outside of the upper cover plates 40 the sidewall sections 70 with the metal mesh arrangement 42 the upper cover sheets 40 over openings 34 , what a 3 not shown, in the inner cover sheets 20 as well as over the porous metal foam core 30 in fluid communication connection. In addition, the central air duct is above the openings in the inner nose plate 84 of the nose portion also with the outside of the nose portion in fluidkommunizierender connection, so that also in this section, an air suction can take place. The metal mesh arrangement 42 in this embodiment, as in the above to the 1a and 1b be executed described.

Based on 3 should the functioning of the structural component 10 for flow laminarization will be explained in more detail below.

On the outside of the structural component 10 is an air flow, which in 3 flows from top to bottom. The air flow first hits the nose section 80 and splits up there. The split flow then follows the two sidewall sections 70 to the subsequent component of an aircraft, which in 3 the sake of clarity is no longer shown. When hitting the air flow in the nose section 80 and when flowing around the side wall sections 70 exists, depending on the flow situation and flow velocity, the risk of the formation of turbulent flow areas. This is prevented by in the central air duct 60 a negative pressure via a at this central air duct 60 connected pump is created. The negative pressure is propagated through the fluid-communicating connection of the central air channel 60 over the openings 34 in the inner cover sheets 20 the side wall portions and through the porous metal foam core 30 and thus lies on the inside of the metal mesh arrangement 42 at. The vacuum applied there sucks air through the metal mesh arrangement 42 and then through the porous metal foam core 30 through and thus takes the air flow on the outside of the side wall sections air. In this way, so by sucking the air from the outside of the side wall sections 70 the formation of turbulence is prevented and the flow is laminarized. The extracted air is through the openings 34 in the inner cover plates in the central air duct 60 guided and transported away from there by means of the pump.

The discharged air can be supplied to other systems of an aircraft, which require the compressed air. These are, for example, the air conditioning of the cabin of the aircraft or other flow control devices that require compressed air. Alternatively, the extracted air via a valve can also be performed overboard.

In addition to the extraction on the side wall sections 70 can in the embodiment of the 3 also on the nose section 80 Air are sucked out of the air flow. This is what the central air duct stands for 60 in direct fluid-communicating contact with the openings 34 in the outer nose plate 84 through which the applied negative pressure on the inside of the outer nose plate 84 Air from the porous metal foam core 30 is sucked inwards. In this way, substantially on the entire outside of the structural component 10 Air in the central air duct 60 sucked and thus performed substantially on the entire outer surface of the structural component a Strömungslaminarisierung.

In the embodiment of the 3 are the sidewall sections 70 integral with the nose portion 80 executed. In particular, the outer nose plate 84 and the outer cover sheets 40 . which each as a metal mesh arrangement 42 are formed, integrally executed. Also the inner cover sheets 20 the side wall sections are integral with the inner nose plate 80 , In this case, advantageously, the openings in the inner cover plates 20 and the inner nose plate 82 in the flat state, ie before producing the desired curvature, generated. Next is a uniform porous metal foam core 30 for the sidewall sections 70 and the nose section 80 available.

In this case, the thickness of the porous metal foam core varies 30 between the sidewall sections 70 and the nose section 80 , Such is the porous metal foam core 30 in the nose section 80 thinner than in the sidewall sections 70 , This allows the nose section 80 a significantly greater curvature than that for the sidewall sections 70 applies. Next is the porous metal foam core 30 with recesses 36 equipped, which with respect to the 4 to 8th will be described in more detail later.

In 2 is an alternative to the embodiment of 3 shown. It differs by the arrangement of the central air duct 60 , This is again through a channel plate 62 however, which in the present embodiment is independent of the sidewall portions 70 namely exclusively with the nose section 80 , in particular its outer nose plate 84 the central air duct 60 forms. The cross section of the central air duct 60 is significantly smaller than in the embodiment of 3 , This gives free space between the side wall sections 70 , which can be used for example for cables or hydraulic lines.

To ensure that the necessary fluid communicating connection between the central air duct 60 the embodiment of the 2 with the outside of the upper cover plates 40 the sidewall sections 70 is present in this embodiment via the openings 34 in the inner cover sheets 20 the sidewall sections 70 Air flow from the side wall sections in an air collection channel 64 sucked and over this the central air duct 60 fed. Here is the air collection channel 64 designed as an annular channel, which at the same time as a stiffening rib for the structural component 10 serves.

In the 4 to 8th Various embodiments of the recesses are now shown in the wall sections, which for the side wall sections 70 and partly also for the nose section 80 can be used.

In 4 the simplest embodiment of the wall section is shown in cross-section. From outside to inside, so in 4 from right to left, the sandwich construction of the wall section builds up successively as follows. After an outer cover plate 40 passing through a metal mesh arrangement 42 is formed, followed by a porous metal core 30 made of a titanium alloy or nickel-iron base, that is generally made of corrosion-resistant material. Inside, the wall section through an inner cover plate 20 completed in which openings 34 available. In 4 as well as in the following 5 to 7 is in each case only a single opening 34 , or only a single aperture 34 shown, but with a plurality of openings over the inner surface of the inner cover plate 20 are distributed. The embodiment of the 4 limits the suction of air to the opening cross-section of the opening 34 , The other areas of the porous metal foam core 30 , which on the inner cover plate 20 Adjacent are not essential for the removal of air flow. The opening cross-section of the openings 34 thus forms the bottleneck in the quantity of suction of the air flow, which can not be arbitrarily increased, otherwise the mechanical stability of the wall section would suffer.

In order to further improve the suction of air flow and still be able to provide a sufficient mechanical stability is in 5 a cross section through two further embodiments shown. After this 5 is the recess 36 either with a spherical boundary surface to the porous metal foam core 30 or with a semi-cylindrical boundary surface to the porous metal foam core 30 fitted. In both cases, the active Absaugungsquerschnitt increases between de recess 36 and the porous metal foam core 30 , In the present case, the Absaugungsquerschnitt the recess 36 about four times as large as the opening cross section of the opening 34 inside cover plate 20 , In this way, the pressure loss is reduced in the interior of the wall portion, so that at the same opening cross-section of the opening 34 inside cover plate 20 a significantly larger amount of air flow can be extracted. It should be noted that for the extraction of the porous metal foam core 30 the active, ie the openly accessible Absaugungsquerschnitt the porous metal foam core 30 is crucial. By providing the recesses 36 in this way this Absaugungsquerschnitt of the opening cross-section of the openings 34 decoupled in the inner cover plate so to speak, and thus also serves as an air collection channel 64 for the suction.

6 Modifies the embodiment of the 5 in that at the contact surface of the recess 36 with the porous metal foam core 30 a reinforcing element 38 is provided. This reinforcing element 38 serves the mechanical support of the recess 36 because through the recess 36 a weakening of the porous metal foam core 30 and thus the wall section is done. This weakening is caused by the reinforcing element 38 mechanically balanced.

The 7 shows the embodiment of the recesses 36 as a substantially rectangular shape. This embodiment is also provided with a reinforcing element 38 providable. 8th shows for all forms of recesses an embodiment as elongated grooves, which are arranged mutually substantially parallel and offset from one another in the longitudinal direction. In 8th It is easy to see that in each recess 36 more than one opening 34 is arranged. In this way, on the one hand an exchange of extracted air flow in the longitudinal direction of the grooves possible, and on the other hand, the active Absaugungsquerschnitt the recesses 36 very much enlarged. In these cases, the active Absaugungsquerschnitt the recesses 36 about 60 times the opening cross-section of the openings 34 in the inner cover sheets.

Of course, the above applies to the recesses 36 explained also for a nose section 80 a structural component 10 with a wall section according to the invention. The connection between the porous metal foam core and the two cover plates 20 and 40 , as well as the two nose plates 82 and 84 can be done via sintering or diffusion bonding.

LIST OF REFERENCE NUMBERS

10

structural component

20

inner cover plate

30

porous metal foam core

34

opening

36

recesses

38

reinforcing element

40

outer cover plate

42

Metal mesh arrangement

44

metal wires

60

central air duct

62

channel plate

64

Air collection channel

66

Sidewall channels

68

nasal passages

70

Sidewall elements

80

nosepiece

82

inner nose plate

84

outer nose plate

Claims (16)

Wall section for use with aircraft airborne components, comprising: an outer cover plate ( 40 ), which is at least permeable to air flow, at least one inner cover plate ( 20 ) with openings ( 34 ) and a porous metal foam core ( 30 ), between the two cover sheets ( 20 . 40 ) and is permeable to air flow and the outer cover plate ( 40 ) against the inner cover plate ( 20 ) is supported. Wall section according to claim 1, characterized in that the outer cover plate ( 40 ) at least partially from a metal mesh arrangement ( 42 ) which is permeable to air flow. Wall section according to claim 1 or 2, characterized in that in the porous metal foam core ( 30 ) Recesses ( 36 ), which passages between the porous metal foam core ( 30 ) and the openings ( 34 ) in the inner cover plate ( 20 ) form. Wall section according to one of the preceding claims, characterized in that the recesses ( 36 ) at least partially have a spherical shape. Wall section according to one of claims 3 or 4, characterized in that the recesses ( 36 ) at least partially have a longitudinal extension and thus elongated grooves in the porous metal foam core ( 30 ), which are arranged along the direction of the longitudinal extent of the grooves one behind the other and / or next to each other. Wall section according to one of claims 3 to 5, characterized in that the recesses ( 36 ) for supporting the porous metal foam core ( 30 ) at least one reinforcing element ( 38 ) which is in contact with the porous metal foam core ( 36 ) and is at least partially permeable to air flow. Structural component ( 10 ) for use with flow components of aircraft having at least two side wall sections ( 70 ), each comprising at least one wall section having the features of one of claims 1 to 5, at least one nose section ( 80 ), which has an outer air permeable outer nose plate ( 84 ) and between the two side wall sections ( 70 ) is arranged and connected to these, and at least one central air duct ( 60 ), which for sucking air from the outside of the outer cover plate ( 40 ) with the permeable metal mesh arrangement ( 42 ) over the openings ( 34 ) and the metal foam core ( 30 ) is in fluid-communicating communication. Structural component ( 10 ) according to claim 7, characterized in that a channel plate ( 62 ) is provided, which together with the outer nose plate ( 84 ) of the nose portion ( 80 ) at least one line section of the central air channel ( 60 ). Structural component ( 10 ) according to claim 7, characterized in that a plurality of channel plates ( 62 ) are provided, which between the two side wall sections ( 70 ) and thus the air duct ( 60 ) form. Structural component ( 10 ) according to one of claims 7 to 9, characterized in that the outer nose plate ( 84 ) of the nose element ( 80 ) also of a metal mesh arrangement ( 42 ) which is permeable to air flow and between the outer nasal plate ( 84 ) and an inner nose plate ( 82 ) also the porous metal foam core ( 30 ) is provided. Structural component ( 10 ) according to claim 10, characterized in that the air collecting channel ( 64 ) is designed as an annular channel which extends between openings ( 34 ) in the inner cover plate ( 20 ) of the side wall section ( 70 ) and the air duct ( 60 ). Structural component ( 10 ) according to one of claims 7 to 11, characterized in that in the porous metal foam core ( 30 ) of the sidewall elements ( 70 ) Sidewall channels ( 66 ) provided by recesses in the porous metal foam core ( 30 ) and between the openings ( 34 ) in the inner cover plate ( 20 ) and the porous metal foam core ( 30 ) of the sidewall sections ( 70 ) establish the fluid-communicating connection. Structural component ( 10 ) according to one of claims 7 to 12, characterized in that the structural component ( 10 ) is an aerodynamic body, wherein the nose portion ( 80 ) a portion of the aerodynamic body with congestion flow and the sidewall portions ( 70 ) Are sections of the aerodynamic body with a boundary layer to be formed. Method for producing a structural component ( 10 ) comprising the features of one of claims 7 to 13, comprising the steps of: • producing a first sidewall portion ( 70 ) • producing at least one second side wall section ( 70 ) • making a nose section ( 80 ) • arranging the nose section ( 80 ) between the two side wall sections ( 70 ) • connecting the nose section ( 80 ) with the two side wall sections ( 70 ) Method according to claim 14, characterized in that the side wall sections ( 70 ) and the nose portion ( 80 ) are produced together by the following steps: Integral shaping of the outer cover sheets ( 40 ) and the outer nasal plate ( 74 ), • arranging the porous metal foam core ( 30 ) on the outer cover plates ( 40 ) and the outer nose plate ( 74 ), • arranging the inner cover plates ( 20 ) and the inner nose plate ( 72 ) on the porous metal foam core ( 30 ) Flow component of an aircraft comprising at least one structural component ( 10 ) having the features of one of claims 7 to 13.

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