CN219008104U - Aircraft trailing edge flap - Google Patents

Abstract

A trailing edge flap of an aircraft which is receivable in a wing flap compartment of said aircraft, the trailing edge flap having a leading edge side, a trailing edge side, an upper surface and a lower surface, the upper surface of the trailing edge flap having a recess, the position of the recess being arranged such that when the trailing edge flap is retracted into the wing flap compartment the recess is completely hidden in the flap compartment, and when the aircraft is in motion and the trailing edge flap extends out of the flap compartment, airflow flows through the recess. The provided trailing edge flap delays and weakens the airflow flow separation of the upper surface of the trailing edge flap under the condition of not adding an additional device, has simple structure and low cost, and has higher engineering applicability.

Description

Aircraft trailing edge flap

Technical Field

The utility model relates to the field of high lift devices of aircraft, in particular to a trailing edge flap of an aircraft.

Background

The lift of an aircraft varies mainly with the speed of flight and the angle of attack. When flying at a high speed, the wings can generate lift force enough to maintain the flight with a small attack angle; at low speeds of flight or taxiing, a larger angle of attack is required to generate sufficient lift. However, the wing shape of the aircraft is optimized to be more suitable for cruise conditions, which results in insufficient wing lift to be generated at low speeds at take-off and landing, even if increased to a critical angle of attack. Therefore, it is necessary to install a lift-increasing device on the wing, so as to shorten the ground running distance of the aircraft in the take-off and landing stage and improve the take-off, landing and climbing performances of the aircraft.

The high lift device mainly comprises a front edge slat, a front edge flap and a rear edge flap, wherein the rear edge flap is positioned at the rear edge of the main wing, and after the wing is opened, the chord length and the wing camber of the wing can be effectively increased, so that the lift coefficient of the aircraft under a small and medium attack angle is improved, and the aerodynamic characteristics of the aircraft are improved. However, when the trailing edge flap is in a large deflection state, as shown in fig. 3b and 4b, the peak value of the pressure coefficient of the head (leading edge side) is very high, so that flow separation is easily induced on the upper surface of the trailing edge flap, thereby causing lift loss, and at the same time, flap vibration may be induced, so that the take-off/landing performance of the aircraft is reduced, and even the situation that the take-off/landing requirement of the aircraft cannot be met may occur.

In order to control this flow separation, solutions are known in which vortex generators, plasma exciters, etc. are mounted on the upper surface of the trailing edge flap. Vortex generators are actually small wings of small aspect ratio mounted vertically on the body surface at a certain mounting angle, so they can generate tip vortices in the head-on airflow as conventional wings, but because of their small aspect ratio, the strength of the tip vortices is relatively strong. After the high-energy wingtip vortex is mixed with the low-energy boundary layer flow at the downstream of the wingtip vortex, energy is transferred to the boundary layer, so that the boundary layer flow field in the reverse pressure gradient can be continuously attached to the surface of a machine body without separation after additional energy is obtained. However, as an external attachment, the vortex generator simultaneously brings about an increase in resistance and is difficult to adapt to different operating states. The plasma exciter utilizes controllable disturbance applied to a flow field in the process of generating plasma by gas discharge to change the speed and vortex boundary conditions of the flow field, thereby realizing flow control and improving the problem of flow separation. However, most of the dielectric barrier discharge plasma exciters adopted at present have limited induced flow field speed, which restricts the application of the technology. Thus, these solutions are capable of effectively controlling flow separation on the upper surface of the trailing edge flap, but still suffer from the drawbacks of complex auxiliary mechanisms, high maintenance costs, limited engineering applications, etc.

Accordingly, there is a need for an improved trailing edge flap that addresses the problems and deficiencies of the prior art discussed above.

Disclosure of Invention

It is therefore an object of the present utility model to provide an improved trailing edge flap which is notched in the upper surface of the trailing edge flap so that the flow direction of the air flow in the upper surface of the trailing edge flap is changed, thereby delaying and reducing the flow separation without adding additional devices.

According to the utility model, there is provided a trailing edge flap of an aircraft, the trailing edge flap being receivable in a wing bay of the aircraft, the trailing edge flap having a leading edge side, a trailing edge side, an upper surface and a lower surface, the upper surface of the trailing edge flap having a recess, the recess being located such that: the recess is completely hidden in the wing flap compartment when the trailing edge flap is retracted into the wing flap compartment, through which recess an air flow flows when the aircraft is in motion and the trailing edge flap extends out of the flap compartment.

According to a further aspect of the disclosure, the recess is positioned at least partly in an airflow flow separation region on the trailing edge flap.

According to yet another aspect of the disclosure, the spanwise width of the groove does not exceed the spanwise width of the airflow flow separation region on the trailing edge flap. Setting the width too wide is not beneficial in reducing flow separation in the flow separation region of the air stream, but rather can affect structural strength by excessively changing the structure of the trailing edge flap.

According to yet another aspect of the disclosure, the depth of the groove is no less than a horizontal plane in which a leading edge line of the trailing edge flap is located. Too deep a depth also does not contribute significantly to reducing flow separation, but rather affects the structural performance of the trailing edge flap.

According to yet another aspect of the present disclosure, the shape of the groove comprises a rectangle, an oblong or an oval. Preferably, the shape of the groove is rectangular.

According to yet another aspect of the present disclosure, the trailing edge flap includes one or more grooves. In the case of an excessively wide flow separation region of the air flow, it is conceivable to provide a plurality of recesses in order not to significantly influence the structure of the trailing edge flap.

According to a further aspect of the disclosure, the recess is arranged close to the leading edge side of the trailing edge flap.

The utility model also proposes an aircraft comprising a trailing edge flap having the aforementioned characteristics.

According to the utility model, the groove is arranged on the upper surface of the trailing edge flap of the aircraft, which is close to the front edge side, so that the pressure at the groove is increased along the airflow direction, and a part of airflow can flow along the groove to the upper surface of the trailing edge flap when the aircraft moves forwards, so that the airflow direction is guided, and the airflow separation phenomenon is improved. The utility model achieves the aim of improving the air flow separation by only partially changing the structure of the trailing edge flap instead of adding additional devices, has simple structure, lower cost and wide application range, and has stronger engineering application value.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the utility model will become apparent from the following detailed description of the embodiments and the accompanying drawings.

Drawings

For a more complete understanding of the present utility model, reference is made to the following description of exemplary embodiments taken in conjunction with the accompanying drawings. The drawings are not intended to limit the utility model to the particular embodiments depicted therein, and are not necessarily to scale. In the accompanying drawings:

FIG. 1 is a top perspective view of a portion of an aircraft trailing edge flap according to a preferred embodiment of the utility model;

FIG. 2 is a bottom perspective view of the aircraft trailing edge flap of FIG. 1;

FIG. 3a is a schematic flow diagram of an upper surface of the aircraft trailing edge flap of FIG. 1;

FIG. 3b is a schematic flow diagram of the upper surface of a trailing edge flap of an aircraft of the prior art;

FIG. 4a is a schematic view of flow-to-wall shear forces of an upper surface of the aircraft trailing edge flap of FIG. 1;

FIG. 4b is a schematic view of flow-to-wall shear of the upper surface of a prior art aircraft trailing edge flap.

List of reference numerals

10 trailing edge flap

10' trailing edge flap of the prior art

101 upper surface

101' prior art upper surface

102. Lower surface of

103. Front edge side

104. Trailing edge side

2. Groove

Detailed Description

The following description of specific embodiments of the utility model refers to the accompanying drawings, which illustrate specific embodiments in which the utility model may be practiced. The embodiments are intended to describe aspects of the utility model in sufficient detail to enable those skilled in the art to practice the utility model. Other embodiments may be utilized and changes may be made without departing from the scope of the utility model. Therefore, the following description of the embodiments should not be taken as limiting. The scope of the utility model is to be defined only by the claims appended hereto, along with the full scope of equivalents to which such claims are entitled. The same reference numbers will be used throughout the drawings and the detailed description to refer to the same or like parts.

As used herein, azimuthal terms such as "forward," "aft," "chordwise," "spanwise," and the like are considered based on the orientation of the trailing edge flap in an operational state. In particular, the "chord direction" is the direction from the leading edge side to the trailing edge side of the trailing edge flap, and the "spanwise direction" is the direction from the side of the trailing edge flap close to the aircraft fuselage to the side thereof remote from the aircraft fuselage.

FIGS. 1 and 2 illustrate a trailing edge flap 10 according to a preferred embodiment of the utility model. As shown, the trailing edge flap 10 of the aircraft has an upper surface 101, a lower surface 102, a leading edge side 103 and a trailing edge side 104. In the inactive state, the trailing edge flap 10 is stowed in a wing-flap compartment of the aircraft; during take-off/landing of the aircraft, the trailing edge flap 10 extends out of the wing cabin, increasing the camber and chord length of the wing. A recess 2 is provided in the upper surface 101 of the trailing edge flap 10 near the leading edge side 103, which recess 2 extends along the chord-wise length of the trailing edge flap, i.e. is arranged such that when the trailing edge flap 10 extends out of the flap compartment, an air flow flowing through the aircraft fuselage flows through the recess 2. Such an orientation makes it possible to guide a part of the air flow flowing over the surface of the trailing edge flap 10 along the recess 2, while locally reducing the pressure on the leading edge side of the trailing edge flap 10, thereby changing the air flow direction of the upper surface of the trailing edge flap 10 and delaying the air flow separation.

In order not to affect the overall aerodynamic performance of the aircraft, the chord-wise length of the groove 2 is dimensioned such that when the trailing edge flap 10 is retracted into the flap compartment, the groove 2 is completely hidden in the flap compartment, preferably being dimensioned to be equal to or slightly smaller than the chord-wise length of the portion of the trailing edge flap 10 that is retracted into the flap compartment. In order to avoid affecting the structural strength of the trailing edge flap 10, the depth of the recess 2 should also be limited. According to a preferred embodiment of the utility model, the depth of the recess 2 is limited to be no lower than the level at which the leading edge line of the leading edge side 103 of the trailing edge flap 10 is located as shown in fig. 2. For a better air flow control effect, the recess 2 is positioned at least partly in the air flow separation region on the trailing edge flap 10 and its spanwise width does not exceed that of this region.

Fig. 3a and 3b compare the flow direction of the upper surfaces of the trailing edge flap 10 according to the utility model and of the trailing edge flap 10 'according to the prior art, and fig. 4a and 4b compare the flow-to-wall shear force of the upper surfaces of the trailing edge flap 10 according to the utility model and of the trailing edge flap 10' according to the prior art. It can be observed that the provision of a groove 2 in the region of the flow separation of the air stream, which has a spanwise width substantially equal to the width of this region, results in a reduced wall shear of the head at the groove 2 and subsequently an increased flow direction compared to the trailing edge flap 10' of the prior art, so that the flow separation of the air stream on the upper surface of the trailing edge flap 10 is retarded and reduced. However, in the case of a relatively wide flow separation region of the air flow, which is, for example, wider than one third of the upper surface 101 of the trailing edge flap 10, the provision of a recess 2 with a corresponding width can significantly influence the structural strength of the trailing edge flap 10, so that it is conceivable to provide two or more recesses 2 for controlling the air flow in sections. According to a preferred embodiment of the utility model, the recess 2 is shaped as a rectangle, but the utility model is not limited thereto, other shapes suitable for guiding the air flow are also conceivable, such as an oblong or oval shape.

The trailing edge flap of the utility model is provided with a recess in its upper surface such that the wall shear at the recess decreases before increasing in the flow direction, and a part of the air flow flowing past the trailing edge flap is guided along the recess, so that the flow separation of the air flow is retarded and reduced. The improved trailing edge flap is not additionally provided with any additional device, has obvious improvement effect, and solves the defects of complex auxiliary mechanism, high maintenance cost and limited engineering application in the prior art.

As used herein, the terms "comprises," "comprising," "includes," "including," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such method, article, or apparatus.

The utility model is not limited to the embodiments described above, which are only illustrative and not restrictive. Any possible variations and modifications can be made by those skilled in the art without departing from the spirit of the utility model and the scope of the claims, given the benefit of this disclosure. Therefore, any modification, equivalent variation and modification of the above embodiments according to the technical substance of the present utility model fall within the protection scope defined by the claims of the present utility model.

Claims (8)

1. An aircraft trailing edge flap receivable in a wing flap compartment of the aircraft, the trailing edge flap having a leading edge side, a trailing edge side, an upper surface and a lower surface,

characterized in that the upper surface of the trailing edge flap is provided with a recess,

the position of the recess is arranged such that when the trailing edge flap is retracted into the flap compartment, the recess is completely hidden in the flap compartment, through which recess an air flow flows when the aircraft is in motion and the trailing edge flap is extended out of the flap compartment.

2. The trailing edge flap of claim 1 wherein the groove is positioned at least partially in an airflow flow separation region on the trailing edge flap.

3. The trailing edge flap according to claim 1 or 2, characterized in that,

the spanwise width of the groove does not exceed the spanwise width of the flow separation region of the air flow on the trailing edge flap.

4. The trailing edge flap of claim 1 wherein the depth of the groove is no less than a horizontal plane in which a leading edge line of the trailing edge flap lies.

5. The trailing edge flap of claim 1 wherein the shape of the groove comprises a rectangle, an oblong, or an oval.

6. The trailing edge flap of claim 1 wherein the trailing edge flap comprises one or more grooves.

7. The trailing edge flap of claim 1 wherein the groove is disposed proximate the leading edge side of the trailing edge flap.

8. An aircraft, characterized in that it has a trailing edge flap according to any one of claims 1-7.

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