A force tunnel test device with jet control airfoil

Abstract

The application discloses a force tunnel test device with a jet control airfoil, and belongs to the technical field of flow control, and at least comprises but is not limited to a test section, end plates, a main airfoil and an airfoil flap; the two side walls of the test section are provided with accommodating cavities for accommodating the end plates, the end plates are movably arranged in the accommodating cavities, the airfoil flap is connected with the main airfoil, the main airfoil is arranged between the two end plates, and one side end plate is connected with a balance through a connecting piece away from the end face of the main airfoil; a bevel is arranged between the airfoil flap and the end plate; the scheme can effectively inhibit the corner separation between the airfoil and the end plate and the wing tip vortex, so that the force test result is closer to the value of a two-dimensional airfoil.

Description

Technical Field

[0001] The invention relates to the technical field of flow control, in particular to a force measuring wind tunnel test device with a jet control airfoil. Background Art

[0002] Transport aircraft are increasingly demanding short takeoff and landing capabilities, and mechanical high-lift devices are no longer sufficient. Flow control technology is a new solution. For transport aircraft, the aerodynamic characteristics of the airfoil largely determine its performance. Therefore, research on flow separation control for airfoil flaps is crucial for developing high-lift devices based on flow control technology.

[0003] At present, there have been many studies on the flow separation control of airfoil flaps at home and abroad. The airfoil wind tunnel test devices used are mostly research devices for studying the aerodynamic characteristics of basic airfoils, that is, keeping the wing section sealed and fixed to the wind tunnel wall and measuring the pressure distribution in the middle section of the wing section in the span direction, or keeping a gap between the wing section and the wind tunnel wall (usually less than 3mm) to facilitate the measurement of the aerodynamic force of the entire wing section (compared with pressure measurement, force measurement is more convenient and direct).

[0004] If the wing section remains sealed and fixed to the wind tunnel wall, a large separation zone (corner separation) will form between the flap and the wall. Research has shown that the span-to-chord ratio of the wing section must be greater than 1.5 to prevent the separation zone from extending to the mid-span of the wing section. If a gap is maintained between the wing section and the wind tunnel wall, not only will this cause corner separation, but the gap will also cause high-pressure airflow from the lower wing surface to flow around to the upper wing surface, forming wingtip vortices. Both corner separation and wingtip vortices will reduce the wing section's lift and increase drag, thus affecting the research results. Summary of the Invention

[0005] The purpose of the present invention is to provide a force measuring wind tunnel test device with a jet-controlled airfoil to address the above-mentioned shortcomings, thereby solving the problem that in the existing technology, when studying the flow separation control of airfoil flaps, there will be corner separation or wingtip vortexes, and corner separation or wingtip vortexes will lead to a decrease in lift and an increase in drag of the wing section, thereby affecting the research results.

[0006] The present invention is achieved through the following solutions:

[0007] A force measuring wind tunnel test device with a jet-controlled airfoil, comprising at least but not limited to a test section, an end plate, an airfoil main wing and an airfoil flap; a receiving cavity for accommodating the end plate is provided on both side walls of the test section, the end plate is movably arranged in the receiving cavity, the airfoil flap is connected to the airfoil main wing, the airfoil main wing is arranged between the end plates on both sides, and one end plate is connected to a balance via a connecting piece on its end surface away from the airfoil main wing; a chamfered portion is provided between the airfoil flap and the end plate.

[0008] Based on the structure of the above-mentioned force-measuring wind tunnel test device with a jet-controlled airfoil, the test section and the end plate are arranged in the same plane, and a gap of a predetermined distance is provided between the two.

[0009] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, the predetermined distance is 5 mm.

[0010] Based on the structure of the above-mentioned force measurement wind tunnel test device with a jet-controlled airfoil, the ratio of the span l of the airfoil to the chord length c of the airfoil when the airfoil flap is not deflected is 2.

[0011] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, when the airfoil flaps are not deflected, the projections of the airfoil main wing and the airfoil flaps on the plate are the airfoil profile, and the distance between the upper end of the airfoil profile and the top of the end plate is the first distance; the distance between the lower end of the airfoil profile and the top of the end plate is the second distance; the distance between the front end and the rear end of the airfoil profile and the two sides of the end plate is the third distance; the value of the first distance is not less than the value of the second distance, and the value of the second distance is not less than the value of the third distance.

[0012] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, the value of the first distance is not less than the value of c, the value of the second distance is not less than the value of c / 2; and the value of the third distance is not less than the value of c / 5.

[0013] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, the airfoil flap includes a first end and a second end, the first end is arranged close to the airfoil main wing, and the second end is arranged away from the airfoil main wing. The span of the airfoil flap is gradually reduced from the first end to the second end, and the beveled portion is arranged on both side walls of the airfoil flap close to the end.

[0014] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, the two sides of the second end are respectively at a fifth distance from the end plate, and a triangular bevel portion is formed between the airfoil flap and the end plate by bevel cutting from the two sides of the first end to the two sides of the second end.

[0015] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, the fifth distance is 1 / 10.

[0016] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, a flow controller is provided at the connection between the airfoil main wing and the airfoil flap; the flow controller is installed on the airfoil main wing or the airfoil flap according to actual needs.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. In this scheme, when it is necessary to experiment on the airfoil, air flow is blown in from one side of the test section, and the aerodynamic force of the entire airfoil is tested by a balance. Since the end plate does not generate lift but only a very small frictional resistance, the force measured by the balance can be considered as the aerodynamic force of the airfoil. It does not need to contact the accommodating cavity, which can ensure the accuracy of the force measurement. At the same time, a bevel is provided between the airfoil flap and the end plate, which can effectively reduce the parameters of the wingtip vortex and avoid its interference with the force measurement results, thereby achieving the effect of increasing the lift of the wing section and reducing the resistance.

[0019] 2. This scheme can effectively suppress the corner separation and wingtip vortex between the airfoil and the end plate, making the force measurement results closer to the values ​​of the two-dimensional airfoil. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the scheme;

[0021] Figure 2 This is the overall rear view of the scheme;

[0022] Figure 3 This is the left view of the whole scheme;

[0023] Figure 4 The streamline diagram near the airfoil surface after applying steady jet control when using the traditional test device;

[0024] Figure 5 This is a streamline diagram near the airfoil surface after applying steady jet control when the present invention is used;

[0025] Figure 6 Schematic diagram of the location of the test plane in the verification test;

[0026] Figure 7 The following are the effect diagrams of the traditional device and the device of this solution in the test experiment;

[0027] Figure 8 Schematic diagram comparing the two-dimensional results of the traditional device and the device of this solution;

[0028] Figure numerals: 1. test section; 2. end plate; 3. airfoil main wing; 4. airfoil flap; 5. balance; 6. chamfered portion; 7. first end portion; 8. second end portion; 9. flow controller. DETAILED DESCRIPTION

[0029] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0030] Any feature disclosed in this specification (including any appended claims and abstract), unless otherwise stated, may be replaced by other equivalent or similar features. In other words, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0031] In the description of the present invention, it should be understood that the terms "up", "down", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a predetermined direction, be constructed and operated in a predetermined direction, and therefore cannot be understood as a limitation on the present invention.

[0032] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features being referred to. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of such features.

[0033] Example 1

[0034] like Figures 1 to 3 The present invention provides a technical solution:

[0035] A force measuring wind tunnel test device with a jet-controlled airfoil, which at least includes but is not limited to a test section 1, an end plate 2, an airfoil main wing 3 and an airfoil flap 4; a receiving cavity for accommodating the end plate 2 is provided on both side walls of the test section 1, the end plate 2 is movably arranged in the receiving cavity, the airfoil flap 4 is connected to the airfoil main wing 3, and the airfoil main wing 3 is arranged between the end plates 2 on both sides, and the end surface of one side end plate 2 away from the airfoil main wing 3 is connected to a balance 5 through a connecting piece; a chamfered portion 6 is provided between the airfoil flap 4 and the end plate 2.

[0036] Based on the above structure, when it is necessary to experiment on the airfoil, air flow is blown in from one side of the test section 1, and the aerodynamic force of the entire airfoil is tested through the balance 5; since the end plate 2 does not generate lift but only generates a very small friction resistance, the force measured by the balance 5 can be considered as the aerodynamic force of the airfoil, which does not need to contact the accommodating cavity, and can ensure the accuracy of the force measurement. At the same time, a beveled portion 6 is provided between the airfoil flap 4 and the end plate 2, which can effectively reduce the parameters of the wingtip vortex and avoid its interference with the force measurement results, thereby achieving the effect of increasing the lift of the wing section and reducing the resistance.

[0037] As an example, the test section 1 and the end plate 2 are arranged in the same plane, and a gap of a predetermined distance is provided between them.

[0038] Based on the above structure, by setting a gap between the test section 1 and the end plate 2, on the one hand, force measurement can be facilitated, and on the other hand, the special setting of the gap can reduce the intensity of the overflow phenomenon caused by the gap.

[0039] As an example, the predetermined gap distance can be 5 mm. The smaller the gap, the weaker the overflow phenomenon caused by the gap, and the smaller the impact on the test results. Taking into account the factors of pneumatics and assembly, in the preferred embodiment of this embodiment, the gap is 5 mm.

[0040] As an example, the span l of the airfoil and the airfoil flap 4 wings are not deflected when the airfoil chord length c ratio is 2;

[0041] Based on the above structure, the greater the ratio of the airfoil's span l to its chord length c when the flap is not deflected (the aspect ratio), the less the impact of corner separation and wingtip vortices on the central portion of the airfoil. In a preferred embodiment, the airfoil's aspect ratio is 2. At this aspect ratio, the impact of corner separation and wingtip vortices on the central portion of the airfoil is minimized.

[0042] As an example, when the airfoil flap 4 is not deflected, the projections of the airfoil main wing 3 and the airfoil flap 4 on the plate are airfoil profiles, and the distance between the upper end of the airfoil profile and the top of the end plate 2 is the first distance; the distance between the lower end of the airfoil profile and the top of the end plate 2 is the second distance; the distance between the front end and the rear end of the airfoil profile and the two sides of the end plate 2 is the third distance; wherein the value of the first distance is not less than the value of the second distance, and the value of the second distance is not less than the value of the third distance.

[0043] As an example, the value of the first distance is not less than the value of c, the value of the second distance is not less than the value of c / 2; and the value of the third distance is not less than the value of c / 5.

[0044] Based on the above structure, the farther the gap between the test section 1 and the end plate 2 is from the airfoil (the larger the end plate 2), the smaller the impact on the test results in theory. However, an oversized end plate 2 is prone to deformation and will induce vibration under the action of the incoming flow. Therefore, the end plate 2 should not be too large. Since the upper surface of the airfoil is the suction surface, the external airflow will be sucked into the test section 1 through the gap, which will have a greater impact on the airfoil flow field. Therefore, the leading and trailing edges and the upper edge of the end plate 2 should be farther away from the airfoil. The lower surface of the airfoil is the pressure surface, and the airflow inside the test section 1 will flow out through the gap, which has less impact on the airfoil flow field. Therefore, the lower edge of the end plate 2 can be closer to the airfoil. That is, this scheme specially sets the upper, lower, left and right distances of the airfoil profile from the end plate 2 according to the impact of the gas entering the end plate 2 on the airfoil flow field, which can further reduce the impact of external factors on the experimental factors.

[0045] As an example, the aerofoil flap 4 may include a first end 7 and a second end 8, the first end 7 is arranged close to the aerofoil main wing 3, and the second end 8 is arranged away from the aerofoil main wing 3. From the first end 7 to the second end 8, the span l1 of the aerofoil flap 4 is gradually reduced, and the beveled portion 6 is arranged on both side walls of the aerofoil flap 4 near the end.

[0046] As an example, the second end 8 is at a fifth distance from the end plate 2 on both sides, and a triangular bevel portion 6 is formed between the airfoil flap 4 and the end plate 2 by beveling from both sides of the first end 7 to both sides of the second end 8; the fifth distance can be 1 / 10.

[0047] Based on the above structure, the wingtip of the airfoil flap 4 is beveled inward from the leading edge of the flap, forming a triangular gap between the flap and the end plate 2. The length of the trailing edge of the airfoil flap 4 removed on each side is 1 / 10. The gap formed by the beveled cut ensures a smooth change in the flow area at that location, preventing the expansion of the fluid in the boundary layer of the upper airfoil end plate 2 and eliminating corner separation. The beveled cut of the flap tip results in a smaller gap between the two at the leading edge of the flap and a larger gap at the trailing edge. The pressure difference between the upper and lower surfaces at the leading edge of the flap is large, and the smaller gap suppresses the bypass flow. The pressure difference between the upper and lower surfaces at the trailing edge of the flap is small, so even with a larger gap, the bypass flow intensity is not strong.

[0048] As an example, a flow controller 9 can be provided at the connection between the airfoil main wing 3 and the airfoil flap 4; the flow controller 9 can be installed on the airfoil main wing 3 or the airfoil flap 4 according to actual needs; the flow controller 9 is used to control the flow separation on the flap, which can be active (jet controller, etc.) or passive (vortex generator, etc.), etc.

[0049] Therefore, compared with the prior art, the present invention effectively suppresses the angular separation and wingtip vortex between the airfoil and the end plate 2, making the force measurement result closer to the value of the two-dimensional airfoil.

[0050] At the same time, this solution conducts a specific simulation of the test of the existing technology and this solution. A monitoring plane is set at the tail of the wing flap 4, and the monitoring results are as follows: Figures 4 to 8 As shown, the results show that in the traditional device, there is a large separation area (low-speed recirculation area), while the low-speed recirculation area of ​​this solution is basically eliminated; at the same time, the lift result of the structure of this patent is closer to the two-dimensional value. It can be seen that by adopting this solution, the angular separation and wingtip vortex between the airfoil and the end plate 2 can be effectively suppressed, making the force measurement result closer to the value of the two-dimensional airfoil.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A force measurement wind tunnel test device with a jet-controlled airfoil, characterized by: The wing profile is configured to have a first end portion and a second end portion, wherein the first end portion is configured to have a first end portion and a second end portion, the first end portion being configured to have a first end portion and a second end portion, the first end portion being configured to have a first end portion and a second end portion, the first end portion being configured to have a first end portion and a second end portion, the first end portion being configured to have a first end portion and a second end portion, the first end portion being configured to have a first end portion and a second end portion, the first end portion being configured to have a first end portion and a second end portion, the 2. The force measurement wind tunnel test device with a jet-controlled airfoil according to claim 1, characterized in that: The predetermined distance is 5 mm.

3. The force measurement wind tunnel test device with a jet-controlled airfoil according to claim 2, characterized in that: Airfoil span l The ratio of the airfoil chord length c to the airfoil chord length when the airfoil flap is not deflected is 2.

4. The force measurement wind tunnel test device with a jet-controlled airfoil according to claim 3, characterized in that: When the aerofoil flaps are not deflected, the projections of the aerofoil main wing and the aerofoil flaps on the plate are the aerofoil profile, and the distance between the upper end of the aerofoil profile and the top of the end plate is the first distance; the distance between the lower end of the aerofoil profile and the top of the end plate is the second distance; the distance between the front end and the rear end of the aerofoil profile and the two sides of the end plate is the third distance; the value of the first distance is not less than the value of the second distance, and the value of the second distance is not less than the value of the third distance.

5. The force measurement wind tunnel test device with a jet-controlled airfoil according to claim 4, characterized in that: The value of the first distance is not less than the value of c, the value of the second distance is not less than the value of c / 2; and the value of the third distance is not less than the value of c / 5.

6. The force measurement wind tunnel test device with a jet-controlled airfoil according to claim 5, characterized in that: The fifth distance is l / 10.

7. A force measurement wind tunnel test device with a jet-controlled airfoil according to any one of claims 1 to 4, characterized in that: A flow controller is provided at the connection between the airfoil main wing and the airfoil flap; the flow controller is installed on the airfoil main wing or the airfoil flap according to actual needs.

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