DE102022115067A1 - Engine cowling for engines - Google Patents

Abstract

The invention relates to an engine cowling for the cowling of a transonic engine of an aircraft with an outer skin which forms a flow surface around which a fluid can flow and has at least one elastically deformable dent region for forming a shock control dent in order to counteract the effects of a transonic shock, and - a buckling actuator, which interacts with the elastically deformable buckling area of the outer skin to form the impact control bump as required, - so that the elastically deformable buckling area can be transferred from a first operating state without impact control bump to a second operating state with impact control bump.

Description

The invention relates to an engine cowling for the cowling of a transonic engine of an aircraft.

Airplanes that fly in a transonic speed range fly at a high subsonic speed. At such speeds in the high subsonic range, supersonic areas form on the aerodynamically flowed wings of the aircraft. These supersonic regions lead to a transonic shock (also called compression shock) in the direction of flow, which contributes to the wave resistance of the aerodynamic surfaces and thus to the overall flow resistance of the aircraft.

In order to mitigate the increase in resistance caused by a compression shock, it is known to provide a shock control bump in the wings in those areas where such a transonic shock is to be expected at high subsonic speeds in order to weaken the transonic shock and thereby reduce the flow resistance and/or the shock-induced shock To reduce or prevent flow separation. Such shock control bumps are also known as Shock Control Bump (SCB). However, at flow speeds well below the speed of sound, at which no supersonic regions form, such a shock control bump is undesirable because it causes an undesirable increase in the overall resistance. Such a shock control bump is therefore only useful if, at a correspondingly high subsonic speed, compression shocks can be avoided and the overall flow resistance can be reduced.

It is therefore known to provide such impact control bumps in the aerodynamic surface of a wing in such a way that the impact control bump can be retracted and extended as required. This means that the wing can be transferred from a first operating condition in which the shock control bump is not present in the outer contour of the surface to a second operating condition in which the shock control bump is present in the outer contour of the surface and attenuate a corresponding compression shock or even avoid it completely.

From the DE 10 2020 116 350 A1 For example, a spoiler of a transonic wing is known in which the shock control bump can be extended via an internal actuator. For this purpose, part of the outer surface of the spoiler is deformed when the shock control bump is extended, which creates a corresponding bump within the surface contour of the spoiler.

Out of T. Bein et al.: “An adaptive spoiler to control the transonic shock”, Smart mater. Struct. 9 (2000) pp. 141 - 148 an adaptive spoiler for forming a shock control bump is also known, the flexible outer skin of which is deformable relative to a load-bearing structure with several actuators arranged one behind the other in between. The actuators each comprise a B-shaped element, which causes a deformation of the outer skin when an internal pressure is applied or when a shape memory alloy partially forming the element is heated above a transition temperature.

Out of LF Campanile et al.: The “Fish-mouth” Actuator: Design Issues and Test Results, Journal of Intelligent Material Systems and Structures, Vol. 15 - September/October 2004, pp. 711-719 , a transonic wing is known with so-called fishmouth actuators arranged one behind the other in front of its trailing edge under a flexible outer skin. Each of the fish mouth actuators can be actuated to raise the area of the outer skin adjacent to it. The fishmouth actuators each have a flat oval or fishmouth-shaped elastic structure in cross section, between whose maximally spaced points a wire made of a shape memory alloy is stretched. When this wire is heated above the transition temperature of the shape memory alloy, it contracts between the narrow sides of the elastic arrangement and thus pushes its long sides apart.

From M. Kintscher et al.: Generation of a Shock Control Bump by Pressurized Chambers, ICAST 2015: 26th International Conference on Adaptive Structures and Technologies, October 14-16, 2015, Kobe, Japan, is a spoiler for a transonic wing with multiple Pressure chambers located one behind the other are known. By applying an internal pressure to the pressure chambers, a shock control bump (SCB) is formed above them, the height and position of which can be controlled by the pressure distribution in the pressure chambers.

Out of L. Hao etal: Numerical analysis on shape memory alloy-based adaptive shock control bump, Journal of Intelligent Material Systems and Structures, 2018, Vol. 29(15), pp. 3055-3066 , it is known for the temporary formation of a Shock Control Bump (SCB) on a wing surface to provide a four-sided clamped plate made of a shape memory alloy, which, when heated to above its transition temperature, changes from a flat shape to the bump shape of the Shock Control Bump (SCB). .

It has been shown that at high subsonic speeds, not only on the wings such a compression shock forms, but also in transonic engines. There, a supersonic region forms on the engine cowling both inside and outside the inlet of the engine, at the end of which the transonic shock forms. On the outside of the engine (external area), this leads to transonic increases in resistance. However, on the inside of the engine (inside the inlet) the shock leads to a shock-induced separation and increases the overall resistance of the engine and consequently of the aircraft.

Out of A. John et al.: Using shock control bumps to improve engine intake performance and operability", Aeronaut. j., Vol. 124, No. 1282, pp. 1913-1944 , December 2020, it is known that at a high angle of attack indoors, a supersonic area can form on the underside of the engine lip in front of the rotor, which can lead to a compression surge. Such a transonic shock in the area of the engine has the disadvantage that not only the overall resistance of the engine is increased, but also shock-induced separation and thus vibrations are introduced into the engine, which can have a detrimental effect on comfort or safety.

Against this background, it is the object of the present invention to provide an improved engine cowling with which compression shocks in supersonic regions in a transonic engine can be avoided or at least reduced.

The task is solved according to the invention with the engine cowling according to claim one. Advantageous embodiments of the invention can then be found in the corresponding subclaims.

• - einer Außenhaut, die an einer Außenseite eine von einem Fluid umströmbare Strömungsoberfläche bildet und mindestens einen elastisch verformbaren Beulbereich zur Ausbildung einer Stoßkontrollbeule hat, um den Auswirkungen eines transsonischen Stoßes entgegenzuwirken, und
• - einem Beulaktuator, der mit dem elastisch verformbaren Beulbereich der Außenhaut zur bedarfsweisen Ausbildung der Stoßkontrollbeule zusammenwirkt,
• - sodass der elastisch verformbare Beulbereich von einem ersten Betriebszustand ohne Stoßkontrollbeule in einen zweiten Betriebszustand mit Stoßkontrollbeule überführbar ist.

According to claim 1, an engine cowling for the outer casing of a transonic engine of an aircraft is proposed, with the following features:

• - an outer skin, which forms a flow surface around which a fluid can flow on an outside and has at least one elastically deformable buckling area to form a shock control bump in order to counteract the effects of a transonic shock, and
• - a buckling actuator which interacts with the elastically deformable buckling area of the outer skin to form the impact control buckle as required,
• - So that the elastically deformable buckling area can be transferred from a first operating state without a shock control buckle to a second operating state with a shock control buckle.

The engine cowling has an outer skin around which the surrounding air can flow on an outside. This outer skin has at least one point an elastically deformable dent area, which is in operative connection with a dent actuator in such a way that a shock control bump (SCB - Shock Control Bump) can be formed by deforming this dent area, if necessary depending on the flight condition of the person in question aircraft. The actuator is designed in such a way that it can transfer the elastically deformable buckling area from a first operating state without a shock control buckle into a second operating state with a shock control buckle, wherein the transfer from the second operating state to the first operating state can also be provided by the buckling actuator.

The inventors have recognized that such a shock control dent on an engine cowling can be realized using an elastically deformable dent area, although an engine cowling generally has to have a very high degree of tightness and is generally extremely curved, often multiple times. However, it has been shown that with the help of such an elastically deformable dent area and an actuator that interacts with it, both 2D and 3D dents can be formed in the outer skin of the engine cowling to implement shock control dents.

It is particularly provided and particularly expedient if the elastically deformable dent area is part of the outer skin, in particular an integral part of the engine cowling. The elastically deformable dent region integrated into the outer skin of the engine cowling can be designed in such a way that it forms part of the outside of the outer skin that can be flowed around.

It is therefore proposed according to the invention that in order to control the flow in and around an engine of an aircraft, in particular a transonic aircraft with the ability to reach a high subsonic speed, as well as to control the partially occurring transonic shock to reduce the shock-induced separation and reduce the current strength using the elastic Deformable dent area corresponding shock control dents are formed in the outer skin of the engine cowling, which are formed in particular in the area surrounding the impact. With the help of the buckling actuator, such a shock control bump can be extended and retracted if necessary, whereby the shock control bump is adaptive or morphing.

The elastically deformable dent area can be provided either on an inner outside of the engine cowling (for example, the area of the cowling lip) or on an outer outside, which usually covers the entire surface of the engine.

It is conceivable that the height of the impact control bump can be varied using the buckling actuator. Accordingly, the buckling actuator is designed such that the height of the shock control bump is variable in the second operating state of the elastically deformable buckling area and can be changed in the second operating state. It is therefore conceivable that, in addition to a first and second operating state, second operating states exist and can be assumed in order, for example, to realize different heights of the shock control bump.

Furthermore, it is conceivable that the buckling actuator is designed such that the position of the shock control bump within the engine cowling is variable. Thus, the shock control bump can be generated at the location within the elastically deformable buckling region where the transonic shock actually occurs. This can be achieved, for example, by providing a plurality of independently acting buckling actuators, which can be controlled independently of one another and thus generate a shock control buckle at their respective positions if necessary.

According to one embodiment, it is provided that the buckling actuator is arranged in or on the outer skin, in particular in or on the outer skin within the elastically deformable buckling area, or that the buckling actuator forms part of the outer skin, in particular the part of the elastically deformable buckling area.

According to one embodiment, it is provided that the elastically deformable dent region is arranged on an inside of a cladding lip which protrudes counter to the flow direction.

The protruding lip of the engine cowling forms a type of cylinder that is provided in front of the inlet into the engine. Particularly on the lower part of the fairing lip, at a moderate angle of attack in front of the rotor of the engine at a high subsonic speed, a supersonic region can form, which induces a transonic shock. With a shock control bump on the lower inside of the fairing lip before the engine inlet, both shock-induced separation and shock intensity can be reduced, thereby mitigating the effects of the supersonic region in this area. For this purpose, the cowling lip of the engine has at least one elastically deformable buckling area on the inside, preferably in the lower area, but at least in the regions in which supersonic regions are to be expected, which is in operative connection with the buckling actuator (inside in the engine cowling), that the elastically deformable dent area can be transferred from a first operating state to a second operating state and, if necessary, back and thus, if necessary, a shock control dent can be formed on the inside of the engine cowling in front of the inlet of the engine.

According to one embodiment, it is provided that a force element of the buckling actuator is embedded in an elastically deformable material. Such a force element can be embedded in the elastically deformable material of the buckling area in such a way that the force element exerts a force on the elastically deformable material and forces it to deform, whereby the impact control dent is formed and the elastically deformable material from the first operating state to the is transferred to the second operating state. Such a force element can be, for example, a linear actuator or, for example, a shape memory alloy.

According to one embodiment, it is provided that the buckling actuator has or consists of a shape memory alloy (FGL) and, when activated, transfers the elastically deformable buckling area into the second operating state or into the first operating state. The shape memory alloy is arranged in the form of one or more SMA elements in the elastically deformable dent area.

It can be provided that the SMA elements contract or stretch when transferring from the first operating state to the second operating state or that the SMA elements bend or straighten when transferring from the first operating state to the second operating state.

Such a shape memory alloy (SMA) can be provided, for example, in the form of wires (SMA wires), plates or grids in the elastically deformable dent area. It is conceivable that SMA elements of different lengths are provided in the elastically deformable dent area, which produce a dent of different heights with the same applied expansion, which can be advantageous for certain applications. However, it is also conceivable that SMA elements of the same length are used.

The shape memory alloy or the SMA elements can be embedded in a flexible, elastically deformable material, such as a flexible EPDM (ethylene-propylene-diene monomer). The elastically deformable area and the buckling actuator form an integral unit and can thus be embedded in the outer skin of the engine cowling flush with the outside of the outer skin.

Because of the deformation of the SMA elements, it is useful for the surrounding structure to be flexible to certain degrees of freedom. If the SMA elements contract in order to change from the first operating state to the second operating state, it is advantageous if relief areas are provided in the structure of the engine cowling, which are located between the rigid engine cowling and the SMA elements. An EPDM material can also be used here.

It is also conceivable that special elastic materials are implemented on the sides of the dents, which allow exploitation over the circumference of the elastically deformable area. EPDM can also be used here. Other materials for this and the other purposes mentioned above can be, for example, silicone, rubber or elastomers.

However, it is also conceivable that an actuator is used, such as that in LF Campanile et al.: The “Fish-mouth” Actuator: Design Issues and Test Results, Journal of Intelligent Material Systems and Structures, Vol. 15 - September/October 2004, S-711-719 is described. Such a buckling actuator in the form of a fish mouth actuator has one or more SMA wires which contract when heated and exert an upward deflection against the flexible outer skin (elastically deformable area) via a spring element (e.g. a glass fiber spring). This deflection transfers the elastically deformable region from the first operating state to the second operating state. By cooling the SMA wires and the restoring tension and force of the spring element (e.g. a fiberglass spring), the actuator is returned to its original, retracted state and the bulging of the flexible area is flattened again.

However, an SMA plate is also conceivable, which is attached to the outer skin of the engine cowling at the 4 corners and, when activated, changes from the first operating state to the second operating state without deforming the outer skin of the engine cowling underneath.

Furthermore, it is also conceivable that an SMA plate is glued flat to an underlying flexible structure or a flexible material, which can also deform upwards when the SMA plate bulges.

According to one embodiment, it is provided that the shape memory alloy is a thermally activated shape memory alloy, wherein the buckling actuator can be brought into operative connection with the engine bleed air for thermal activation and/or wherein the buckling actuator can be brought into operative connection for thermal activation with the heat source of an engine de-icing system or a cooling system.

It can be provided that, using a valve or bypass, heat from the external systems, for example the heat from special engine systems or the engine itself, is diverted to the shape memory alloy if necessary in order to activate the shape memory alloy and thus from the first operating state to the second operating state change.

A cold air stream can be used to cool the shape memory alloy more quickly if the normal cooling rate is not high enough to retract the shock control bump and return it to the first operating state.

According to one embodiment, it is provided that the buckling actuator has or consists of at least one piezoelectric element and, when activated, transfers the elastically deformable buckling area into the second operating state or into the first operating state. Such a piezoelectric element can be integrated into an elastically deformable material in the same way as an element made of a shape memory alloy, for example implemented using wires or planar actuators.

According to one embodiment, it is provided that the buckling actuator has one or more chambers which deform when pressure is applied to a chamber side that is operatively connected to the elastically deformable buckling area, so that when pressure is applied, the elastically deformable buckling area is transferred to the second operating state.

The chambers can be pressurized with a fluid, for example air, gaseous fluid or a liquid fluid.

The chambers or cells are expediently installed under a flexible skin. Here too, an air flow from the engine or from the environment can be tapped for pressurization, for example the bleed air. Closed systems, such as kinematics, pneumatics or hydraulics, are also conceivable.

It is also conceivable to realize the formation of a shock control dent using deformable pressure hoses, which dent a flexible skin that consists of an elastomer and is reinforced, for example with a metal wire mesh and/or a flexible sandwich core. By printing on the pressure hose and the associated deformation of the pressure hose, a leverage effect is achieved through which the elastically deformable area can be transferred from the first operating state to the second operating state.

A construct is also conceivable in which two hoses are used and are placed on the inside of the engine cowling around the entire circumference of the engine. Here too, elastic skin is bulged out by the tube located further out. By applying pressure to a pressure hose located further inside, it rotates and, via a connection to the hose located further outside, this hose can be moved further outwards or inwards, depending on the pressure on the hose located further inside. Further inside means the direction facing away from the engine cowling, while further outside means in the direction of the engine cowling.

Alternatively, a hose can be placed between a structure, which is then pushed apart when pressure is applied and the hose expands, thus forming the shock control bump.

It is also conceivable and encompassed by the idea of the invention that conventional electrical and hydraulic buckling actuators are provided, which are either arranged directly under the surface of the elastically deformable area and are in operative connection with it and can thus form a shock control bump or which have joints and levers (for example toggle joint ) are in operative connection with the elastically deformable dent area and can thus form a shock control dent.

According to one embodiment, it is provided that the actuator is connected to a lever at a first lever end, which is rotatably mounted and connected to the elastically deformable dent region with the opposite second lever end, so that when the lever is actuated by the actuator, the elastically deformable dent region is transferred to the second operating state or to the first operating state.

According to one embodiment, it is provided that the buckling actuator is in operative connection with the elastically deformable buckling area via a roller, roller and/or wedge inside the engine cowling in such a way that the roller, roller and/or is used to transfer the elastically deformable buckling area into the second operating state the wedge is pressed from the inside towards the outside of the engine cowling.

According to one embodiment, it is provided that the dent actuator has one or more chambers, one side of which is formed by the elastically deformable dent region of the outer skin, with a pressure (e.g. a negative pressure) being set or adjustable in the at least one chamber in such a way that Formation of a transonic shock, the elastically deformable buckling area is transferred to the second operating state.

There are different pressure levels in the environment of a transonic shock. The pressure in the supersonic region is lower than the pressure in the subsonic flow. This pressure difference can now be used by setting a corresponding pressure in the chamber with the elastically deformable dent area to automatically form a limited impact control dent if the pressure conditions are such that a transonic impact occurs. By controlling the pressure in the cavity, the dent can be controlled to a limited extent.

According to one embodiment, it is provided that one or more sensors for detecting a transonic impact are provided in the outer skin, which are connected to an evaluation unit, the evaluation unit activating the buckling actuator when detecting a transonic impact and the elastically deformable buckling area from the first operating state transferred to the second operating state.

• 1 schematische Darstellung der Ausbildung eines transsonischen Stoßes an einer Lippe einer Triebwerksverkleidung;
• 2 schematische Darstellung einer Ausführungsform des elastisch verformbaren Beulbereiches mit FGL-Drähten;
• 3 schematische Darstellung (Draufsicht auf die untere Triebwerkslippe) einer Ausführungsform mit FGL eingebettet in ein umgebendes elastisch verformbares Material;
• 4 schematische Darstellung (Seitenansicht) einer Ausführungsform mit FGL in EPDM in starrer Verkleidungsstruktur;
• 5 schematische Darstellung (Seitenansicht) einer Ausführungsform eines FGL-Elementes zwischen EPDM-Strukturen in der Außenhaut;
• 6 schematische Darstellung einer Ausführungsform mit Druckkammern;
• 7 schematische Darstellung einer Ausführungsform mit Doppelschlauchkonstruktion;
• 8 schematische Darstellung einer Ausführungsform mit eingebettetem Druckschlauch;
• 9 schematische Darstellung einer Ausführungsform mit direkter Aktuatorbetätigung;
• 10 schematische Darstellung einer Ausführungsform mit indirekter Aktuatorbetätigung über nachgiebiege Strukturen und zwei Beulen;
• 11 schematische Darstellung weiterer Ausführungsformen mit indirekter Aktuatorbetägigung über eine Stab-Gelenk-Konstruktion;
• 12 schematische Darstellung von Ausführungsform mit Rollen- und Keilbetätigung;
• 13 schematische Darstellung einer Ausführungsform mit passiver Ausbeulung aufgrund der Druckunterschiede in der Umgebung des transsonischen Stoßes.

The invention is explained in more detail with reference to the accompanying figures. Show it:

• 1 schematic representation of the formation of a transonic shock on a lip of an engine cowling;
• 2 Schematic representation of an embodiment of the elastically deformable dent area with SMA wires;
• 3 Schematic representation (top view of the lower engine lip) of an embodiment form with SMA embedded in a surrounding elastically deformable material;
• 4 Schematic representation (side view) of an embodiment with FGL in EPDM in a rigid cladding structure;
• 5 Schematic representation (side view) of an embodiment of an SMA element between EPDM structures in the outer skin;
• 6 schematic representation of an embodiment with pressure chambers;
• 7 schematic representation of an embodiment with a double hose construction;
• 8th schematic representation of an embodiment with embedded pressure hose;
• 9 schematic representation of an embodiment with direct actuator actuation;
• 10 Schematic representation of an embodiment with indirect actuator actuation via flexible structures and two dents;
• 11 schematic representation of further embodiments with indirect actuator actuation via a rod-joint construction;
• 12 Schematic representation of embodiment with roller and wedge actuation;
• 13 Schematic representation of an embodiment with passive buckling due to the pressure differences in the area of the transonic shock.

1 shows a schematic representation of a front cross section through an engine cowling 100 and an engine. The fairing lip 110 is shown with the upper lip section 111 and the lower lip section 112. The rotor 120 of the engine is only indicated schematically. The engine cowling has an outer skin 113, which forms an outside along which the air flow is guided.

In some situations, for example when taking off the aircraft, such a transonic engine is subjected to flow at a high subsonic speed and at the same time at a comparatively high angle of attack α. Before a flow hits the leading edge of the fairing lip 112, this flow has subsonic speed 130. This subsonic speed 130 arises on the lower fairing lip 112 due to the in 1 shown angle of attack α a supersonic region 132, which then generates a transonic shock 134 on the inner outside of the engine cowling 100. This shock wave 134 leads to an increase in resistance or, as in 1 , to the shock-induced flow separation.

At a lower angle of attack a, as is generally the case in cruise flight, and at a high subsonic speed, the transonic shock 134 usually occurs on the outer side of the engine cowling 100, which in 1 however, is not shown.

To control the flow in and around engines as well as to control the partially occurring transonic shock 134 (to reduce the shock-induced separation and reduce the shock strength and thus the resistance), an elastically deformable buckling area is created in the area of the supersonic region 132 or in the area of the transonic shock 134 provided in the outer skin 113, which generates a shock control bump in the outer contour of the engine cowling 100 via a bump actuator. In this way, the effect of a transonic shock 134 can be mitigated or completely reduced.

Particularly in the area of the front turbine inlet section, where the supersonic region 132 and the transonic shock 134 are formed, such an elastically deformable buckling area is provided in the outer skin 113 of the engine cowling 100 in order to best counteract the effects of the transonic shock 134.

However, transonic shocks 134 can also form further back (in the flow direction) on the engine cowling 100, depending on the shape and type of the engine, operating status and the current inflow conditions, which is why this invention also includes the use of adaptive shock control bumps in such turbine areas.

The following figures show embodiments of how such an elastically deformable buckling area can be realized with a buckling actuator in the engine cowling of an engine.

2 shows an embodiment in which the elastically deformable dent region 200 consists of an elastic material or has such an elastic material and in which in or on the elastically deformable material of the dent region 200 SMA elements 210 (e.g. wires or wire-shaped) are made of a Shape memory alloy (SMA) are provided. These SMA elements 210 can have different lengths, whereby different dent contours can be realized.

The direction of contraction 220 is indicated by the arrows. In the first operating state, in which the elastically deformable buckling region 200 does not form a shock control buckle, the SMA elements 210 are in a non-contracted form. At Activation of the SMA elements 210, for example by heating, contract the SMA elements 210 and deform the elastically deformable dent area 200 so that a shock control dent is created in the desired type and contour. Due to the different lengths of the SMA elements 210, different heights of the impact control bump can be achieved. In this way, 3D bumps in particular can be realized.

The SMA elements 210 form a buckling actuator that interacts with the elastically deformable buckling area 200 and is connected to the buckling area 200 in such a way that the buckling area 200 is deformed by activating the buckling actuator. The SMA elements 210 can in particular be integrally integrated into the elastically deformable dent area 200 (material-bonded) or can be glued over the entire surface on an inside.

According to the invention, this elastically deformable dent region 200 can itself form the outside around which the flow flows. However, it is also conceivable that this elastically deformable dent area is additionally covered by an elastic film or another elastic material in order to avoid damage to the SMA elements 210 and to ensure thermal insulation.

In addition to the embodiment shown in the form of wires, plates or grids can also be used.

3 shows an exemplary embodiment in which the SMA element 310 is embedded in a figure-of-eight shape in the elastically deformable dent region 300. The elastically deformable dent region 300 is formed from a flexible material such as EPDM (ethylene-propylene-diene monomer), which forms an elastic body 330 in which the SMA element 310 is embedded. Here too, the embedded SMA element 310 forms a buckling actuator to form the shock control buckling. The FGL element together with the EPDM forms one in this 3 rectangular “elastically deformable dent area”. This area in turn lies in a rigid structure of the turbine, which also includes the turbine lip.

4 shows an exemplary embodiment in which the elastic body 430, which can also be formed from an EPDM, is embedded in a rigid structure 440. The SMA elements 410 are arranged on a top side 432 of the elastic body 430, so that an elastically deformable buckling area 400 with an integrated buckling actuator is created. The elastic body 430 serves in particular as a relief area for the structure when the buckling actuator is activated.

5 shows a further exemplary embodiment in which the SMA element or elements 510 are arranged between two elastic regions 530a, 530b. On the other hand, the elastic areas are connected to the rigid structure 540 of the engine cowling, so that the SMA elements 510 can deform accordingly when activated and can thus form a shock control dent in the elastically deformable area 500.

The buckling actuators shown in the exemplary embodiments in the form of SMA elements are in particular thermally activated in order to form the shock control buckle.

The thermal activation can be carried out, for example, by heat that is tapped from the engine's bleed air or from the engine's "hot air" current. Electrical and inductive heating systems are also conceivable, as well as a combination with a de-icing system, which basically creates heat input into the engine cowling structure. The removal of excess heat from cooling systems is also conceivable. The buckling actuator with the shape memory alloy is connected to the corresponding heat source if necessary and can thus be activated accordingly. This can be done, for example, using valves, a bypass or, in the case of electrical systems, using an appropriate control system.

6 shows an exemplary embodiment in which the elastically deformable region 600 has three pressure chambers 610 which can be pressurized. The number of pressure chambers is variable. The elastically deformable area is embedded in the rigid structure 640 of the engine cowling. At least the upper side 612 (outside) of the pressure chambers 610 is designed to be elastic and deforms out of the contour of the engine cowling when the interior of the pressure chambers 610 is acted upon. The chamber walls can also be designed to be flexible. It is also conceivable that the entire pressure chambers made of an elastic material are embedded in a support structure, whereby only the upper side 612 is deformed.

The system can use the air flows also present in the engine to generate the necessary pressure in the pressure chambers 610. With the help of appropriate valves and the valve position, part of the pressurized air flow can be diverted and into the pressure chamber mern 610 are deflected in order to generate a corresponding pressure, which bulges the upper side 612 of the pressure chambers 610.

By applying different pressures in the respective pressure chambers, the shape of the shock control bump can be varied and individually adapted to the prevailing conditions.

In the exemplary embodiment 6 The pressure chambers 610 together with the pressure source, not shown, thus form the buckling actuator in the sense of the present invention.

7 shows an exemplary embodiment in which the actuator 710 consists of two pressure hoses 712, 714, which are connected to one another via a connecting element 716. This actuator arrangement 710 is arranged on the inside of the engine cowling 740, specifically in the area in which the elastically deformable area 700 is also located.

If the lower, further inner pressure hose 714 is now pressurized, it expands and thereby winds up the connecting element 716 connected between the two pressure hoses 712, 714, as a result of which the upper, further outer pressure hose 712 is displaced with respect to its vertical position. This allows an outward force to be exerted on the elastically deformable region 700. As long as the pressure hose 714 located further inside is pressurized, no shock control dent occurs. When the pressure is reduced, the connecting element 716 unwinds and creates the shock control bump.

8th shows an exemplary embodiment in which a pressure hose 810 is embedded as a buckling actuator in a zigzag structure 812. The pressure hose 810 is integrated in a honeycomb structure in the form of a positive fit. If the pressure hose 810 is pressurized, it pushes the zigzag structure 812 apart, the structure 812 being in operative connection with the elastically deformable area in such a way that a shock control bump results on the outer skin.

9 shows an exemplary embodiment in which linear actuators 910 are in operative connection with the elastic outer skin 900 and form a corresponding shock control bump by shifting outwards by the linear actuators 910. In addition to the actuators 910, stiffening areas 920 can be provided in order to make the outer skin less sensitive. The stiffening areas 920 have a stiff contour arch 922 which rests on the inside of the outer skin of the engine cowling. The area 924 lying between the rigid contour arch 922 and the outer skin 930 can be filled with a highly flexible material, for example EPDM. With the help of this contour arch 922, a desired dent shape can be achieved.

10 shows a special embodiment in which two dents are provided in the outer skin 1030, only one linear actuator 1010 being necessary for this. A rigid or flexible lever element 1011 is connected to a linear actuator 1010, with the lever element 1011 being mounted on two pivot bearings 1012. At the two ends of the lever, the construction is in operative connection with the outer skin 1030 and can form the shock control dents there. Above the linear actuator 1010 there is a flexible structure 1020, which is flattened in the first operating state (lower illustration) and thus creates a smooth, dent-free contour on the outer skin 1030, while in the second operating state (upper illustration) the flexible structure 1020 is bent up to follow the contour when the shock control bump is formed by the lever end. By actively connecting the flexible structure 1020 to the outer skin 1030, the minimum between the two dent maxima can always be shaped as desired and depending on the dent heights.

In the 11 2 further exemplary embodiments are shown in which a shock control bump can be generated using a linear actuator. In the illustration above, a toggle joint is shown that instead of the flexible area from the 10 has a swivel joint on the outer skin 1130. By moving the linear actuator, the shock control bump is retracted and extended.

There are also combinations from the picture above 11 and the 10 conceivable, in which flexible elements and rigid rod-joint systems complement each other.

In the picture below the 11 An exemplary embodiment is shown in which only one lever and one actuator is provided for each bump.

In the 12 The figure above shows an exemplary embodiment in which the impact control bump is implemented using a roller or roller. The roller or roller is pressed against the outer skin from the inside and thus creates a dent contour on the surface to form the shock control dent.

The figure below shows an example of how this can be done using a wedge element can be realized, which is rotated about its longitudinal axis and can therefore form a bump of different heights and possibly in different positions depending on the angle of rotation.

13 shows an exemplary embodiment in which the impact control bump is generated passively. For this purpose, there is a cavity 1340 in the engine cowling 1330, which is subjected to a negative pressure. The subsonic range can have a negative pressure of 0.4 bar, while in the supersonic range, at the point where a transonic shock is formed, a higher negative pressure of 0.6 bar is usually formed.

This pressure difference can be used to passively create a shock control bump in the engine cowling. For this purpose, a pressure in the cavity 1340 is set so that when a transonic shock is formed by the flexible outer skin, a shock control bump is generated that counteracts this.

Reference symbol list

100

engine cowling

110

fairing lip

111

upper lip section

112

lower lip section

113

Outside

120

Engine rotor

130

Air flow at subsonic speeds

132

Airflow at supersonic speeds (supersonic regions)

134

transonic collision

200

elastically deformable dent area

210

SMA element/wires/buckling actuator

220

Direction of contraction of the SMA elements

300

elastically deformable dent area

310

SMA element/buckling actuator

330

elastic body

400

elastically deformable dent area

410

SMA element/buckling actuator

430

elastic body

432

Surface of the elastic body

440

rigid structure of the engine cowling

500

elastically deformable area

510

FGL elements

530

elastic areas

540

rigid structure of the engine cowling

600

elastically deformable area

610

Pressure chambers

612

elastic upper area of the pressure chambers

640

rigid structure of the engine cowling

700

elastically deformable area

710

actuator

712

upper hose of the actuator

714

lower hose of the actuator

716

Connecting element between the hoses

740

engine cowling

810

pressure hose

812

Zigzag structure

900

elastically deformable area

910

Linear actuators

920

stiffening area

922

contour arch

924

filling material

930

outer skin

1010

Linear actuator

1011

Lever element 1011

1012

Pivot bearing

1020

yielding structure

1030

outer skin

1130

outer skin

1330

engine cowling

1340

cavity

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

• DE 102020116350 A1 [0005]

Non-patent literature cited

• T. Bein et al.: “An adaptive spoiler to control the transonic shock”, Smart mater. Struct. 9 (2000) pp. 141 - 148 [0006]
• L. F. Campanile et al.: The “Fish-mouth” Actuator: Design Issues and Test Results, Journal of Intelligent Material Systems and Structures, Vol. 15 - September/October 2004, pp. 711-719 [0007]
• L. Hao etal: Numerical analysis on shape memory alloy-based adaptive shock control bump, Journal of Intelligent Material Systems and Structures, 2018, Vol. 29(15), pp. 3055-3066 [0009]
• A. John et al.: Using shock control bumps to improve engine intake performance and operability", Aeronaut. j., Vol. 124, No. 1282, pp. 1913-1944 [0011]
• L. F. Campanile et al.: The “Fish-mouth” Actuator: Design Issues and Test Results, Journal of Intelligent Material Systems and Structures, Vol. 15 - September/October 2004, S-711-719 [0032]

Claims (13)

Engine cowling (100, 740, 1330) for the cowling of a transonic engine of an aircraft - an outer skin (930), which forms a flow surface around which a fluid can flow on an outside (113) and has at least one elastically deformable dent region (200, 300, 400, 500, 700, 800, 900) to form a shock control dent, around which to counteract the effects of a transonic shock (134), and - a buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010), which is used with the elastically deformable buckling area (200, 300, 400, 500, 700, 800, 900) of the outer skin (930). If necessary, the formation of the impact control bump works together, - So that the elastically deformable buckling area (200, 300, 400, 500, 700, 800, 900) can be transferred from a first operating state without impact control bump to a second operating state with impact control bump. Engine cowling (100, 740, 1330). Claim 1 , characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) is in or on the outer skin (930), in particular in or on the outer skin (930) within the elastically deformable buckling area ( 200, 300, 400, 500, 700, 800, 900), or that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) forms part of the outer skin (930), in particular the Part of the elastically deformable dent area (200, 300, 400, 500, 700, 800, 900). Engine cowling (100, 740, 1330). Claim 1 or 2 , characterized in that the elastically deformable dent region (200, 300, 400, 500, 700, 800, 900) is arranged on an inside of a cladding lip (110) which projects against the direction of flow. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that a force element of the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) is embedded in an elastically deformable material. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) has or consists of a shape memory alloy and when activated the elastically deformable buckling area (200, 300, 400, 500, 700, 800, 900) is transferred to the second operating state or to the first operating state. Engine cowling (100, 740, 1330). Claim 5 , characterized in that the shape memory alloy is a thermally activated shape memory alloy, wherein the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) can be brought into operative connection with the engine bleed air for thermal activation and/or wherein the Bulging actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) can be brought into operative connection for thermal activation with the heat source of an engine de-icing system or a cooling system. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) has or consists of at least one piezoelectric element and When activated, the elastically deformable buckling area (200, 300, 400, 500, 700, 800, 900) is transferred to the second operating state or to the first operating state. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) has one or more chambers which open when pressurized deform a chamber side that is in operative connection with the elastically deformable dent area (200, 300, 400, 500, 700, 800, 900), so that when pressure is applied, the elastically deformable dent area (200, 300, 400, 500, 700, 800, 900) is transferred to the second operating state. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) is connected to a lever at a first lever end, which rotatably mounted and connected to the elastically deformable dent region (200, 300, 400, 500, 700, 800, 900) with the opposite second lever end, so that when the lever is actuated by the actuator (710), the elastically deformable dent region (200 , 300, 400, 500, 700, 800, 900) is transferred to the second operating state or to the first operating state. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) is connected to the elastically deformable dent area (200, 300, 400, 500, 700, 800, 900) is in operative connection in such a way that the elastically deformable dent area (200, 300, 400, 500, 700, 800, 900) is transferred into the second operating state, the roller, roller and / or the wedge is pressed from the inside towards the outside (113). Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) has one or more chambers, one side of which is through the elastically deformable dent region (200, 300, 400, 500, 700, 800, 900) of the outer skin (930) is formed, wherein a pressure in the at least one chamber is set or adjustable in such a way that when a transonic shock (134) is formed elastically deformable dent area (200, 300, 400, 500, 700, 800, 900) is transferred to the second operating state. Engine cowling (100, 740, 1330) according to one of the preceding claims, characterized in that one or more sensors for detecting a transonic shock (134) are provided in the outer skin (930), which are connected to an evaluation unit, the evaluation unit when detecting a transonic impact (134), the buckling actuator (210, 310, 410, 510, 610, 710, 810, 910, 1010) is activated and the elastically deformable buckling area (200, 300, 400, 500, 700, 800, 900) transferred from the first operating state to the second operating state. Airplane with at least one engine having an engine cowling according to one of the preceding claims.

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