Force measurement wind tunnel test device with jet flow control airfoil profile

Abstract

The invention discloses a force measurement wind tunnel test device with a jet flow control airfoil profile, which belongs to a flow control technology and at least comprises but is not limited to a test section, an end plate, an airfoil profile main wing and an airfoil profile flap, accommodating cavities for accommodating the end plates are formed in the side walls of the two sides of the test section, the end plates are movably arranged in the accommodating cavities, the airfoil flap is connected with the airfoil main wing, the airfoil main wing is arranged between the end plates on the two sides, and the end face, far away from the airfoil main wing, of the end plate on one side is connected with the balance through a connecting piece; beveling parts are arranged between the wing-shaped flaps and the end plates; according to the scheme, angular separation and wingtip vortex between the airfoil profile and the end plate can be effectively inhibited, so that the force measurement result is closer to the value of a two-dimensional airfoil profile.

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 have an increasingly urgent need for short takeoff and landing capabilities, and mechanical lift-enhancing devices can no longer meet the demand. The use of flow control technology is a new solution. For transport aircraft, the aerodynamic characteristics of the airfoil largely determine the aerodynamic characteristics of the wing. Therefore, research on airfoil flap flow separation control is of great significance for the development of high-lift devices based on flow control technology.

[0003] At present, there have been many studies on 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 of 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 is kept sealed and fixed to the wind tunnel wall, a large separation zone (corner separation) will be formed between the flap and the wall. Studies have shown that the ratio of the wing section span to the chord length must be greater than 1.5 to ensure that the separation zone does not spread to the middle section of the wing section spanwise. If there is a gap between the wing section and the wind tunnel wall, it will not only cause corner separation, but the gap will also cause the high-pressure airflow on the lower wing surface to bypass the upper wing surface, forming a wingtip vortex. Both corner separation and wingtip vortex will lead to a decrease in lift and an increase in drag on the wing section, 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 deficiencies, thereby solving the problem that in the prior art research on airfoil flap flow separation control, there will be corner area separation or wingtip vortexes, and corner area 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 scheme: A force measuring wind tunnel test device with a jet-controlled airfoil, at least including but not limited to a test section, an end plate, an airfoil main wing and an airfoil flap; a receiving cavity for receiving 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 through 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.

[0007] 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 arranged between the two.

[0008] 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.

[0009] Based on the structure of the above-mentioned force measuring 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.

[0010] Based on the structure of the above-mentioned force measuring wind tunnel test device with a jet-controlled airfoil, when the airfoil flap is not deflected, the projection of the airfoil main wing and the airfoil flap on the plate is 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.

[0011] 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.

[0012] 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 chamfered portion is arranged on both side walls of the airfoil flap close to the ends.

[0013] 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 beveling from the two sides of the first end to the two sides of the second end.

[0014] 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.

[0015] 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.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this scheme, when it is necessary to experiment on the airfoil, airflow 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 generates very small friction resistance, the force measured by the balance can be considered as the aerodynamic force of the airfoil, which does not need to contact the accommodating cavity, and the accuracy of the force measurement can be guaranteed. At the same time, a chamfered portion 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.

[0017] 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

[0018] Figure 1 It is a schematic diagram of the overall three-dimensional structure of this scheme; Figure 2 This is the overall rear view of the scheme; Figure 3 This is the left view of the whole scheme; Figure 4 The streamline diagram near the airfoil surface after applying steady jet control when using the traditional test device; Figure 5 The streamline diagram near the airfoil surface after the steady jet control is applied when the present invention is used; Figure 6 Schematic diagram of the location of the test plane in the verification test; Figure 7 The effect diagram of the traditional device and the device of this solution in the test experiment; Figure 8 A schematic diagram showing the comparison of the two-dimensional results between the traditional device and the device of this scheme; 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

[0019] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0020] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other alternative features that are equivalent or have similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0021] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. 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.

[0022] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0023] Example 1 like Figure 1~Figure 3 The present invention provides a technical solution: 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 receiving 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, 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.

[0024] 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 to be the aerodynamic force of the airfoil, and it does not need to contact the accommodating cavity, so the accuracy of the force measurement can be guaranteed. 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.

[0025] 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 arranged between the two.

[0026] 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.

[0027] As an example, the gap of the predetermined distance may be 5 mm. The smaller the gap is, the weaker the overflow phenomenon caused by the gap is, and the smaller the impact on the test results is. Taking into account the factors of pneumatics and assembly, in the preferred solution of this embodiment, the gap is 5 mm.

[0028] As an example, the ratio of the span l of the airfoil to the chord length c of the airfoil when the airfoil flap 4 wings are not deflected is 2; Based on the above structure, the larger the ratio of the span l of the airfoil to the chord length c of the airfoil when the flap is not deflected (aspect ratio), the smaller the influence of the angular zone separation and the wingtip vortex on the middle part of the airfoil. In the preferred scheme of this embodiment, the aspect ratio of the airfoil is 2. Under the condition of this aspect ratio of the airfoil, the influence of the angular zone separation and the wingtip vortex on the middle part of the airfoil can be reduced.

[0029] 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 upper end of the airfoil profile is at a first distance from the top of the end plate 2; the lower end of the airfoil profile is at a second distance from the top of the end plate 2; the front and rear ends of the airfoil profile are at a third distance from both sides of the end plate 2; 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.

[0030] 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.

[0031] 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 is), the smaller the impact on the test results will be 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 internal airflow of the test section 1 will flow out through the gap, which has a smaller 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.

[0032] 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 chamfered portion 6 is arranged on the two side walls of the aerofoil flap 4 near the ends.

[0033] 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 may be 1 / 10.

[0034] Based on the above structure, the wing tip 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, and the length of the trailing edge of the airfoil flap 4 cut off on each side is 1 / 10. The gap formed by the bevel makes the flow area change smoothly, avoiding the expansion of the fluid in the boundary layer of the upper wing end plate 2 and eliminating the separation of the corner area. The beveled flap tip makes the gap between the two smaller at the leading edge of the flap and larger 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 if the gap is large, the bypass flow intensity is not large.

[0035] 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.

[0036] Therefore, compared with the prior art, the present invention effectively suppresses the corner separation and wingtip vortex between the airfoil and the end plate 2, so that the force measurement result is closer to the value of the two-dimensional airfoil.

[0037] At the same time, this scheme conducts a specific simulation of the test of the prior art and this scheme, and a monitoring plane is set at the tail of the wing flap 4. The monitoring results are as follows: Figure 4~Figure 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.

[0038] 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 protection scope of the present invention.

Claims

1. A force measuring wind tunnel test device with a jet-controlled airfoil, characterized in that: It at least includes a test section, an end plate, an aerofoil main wing and an aerofoil flap; a receiving cavity for receiving the end plate is provided on both side walls of the test section, the end plate is movably arranged in the receiving cavity, the aerofoil flap is connected to the aerofoil main wing, the aerofoil main wing is arranged between the end plates on both sides, wherein the end surface of one end plate away from the aerofoil main wing is connected to the balance through a connecting piece; a chamfered portion is provided between the aerofoil flap and the end plate.

2. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 1, characterized in that: The test section and the end plate are arranged in the same plane, and a gap of a predetermined distance is arranged between the two.

3. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 2, characterized in that: The predetermined distance is 5 mm.

4. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 3, characterized in that: 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.

5. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 4, characterized in that: When the airfoil flap is not deflected, the projection of the airfoil main wing and the airfoil flap on the plate is an airfoil profile, and the upper end of the airfoil profile is at a first distance from the top of the end plate; the lower end of the airfoil profile is at a second distance from the top of the end plate; the front end and the rear end of the airfoil profile are at a third distance from both sides of the end plate; 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.

6. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 5, 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.

7. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 6, characterized in that: The aerofoil flap comprises a first end and a second end, wherein the first end is arranged close to the aerofoil main wing, and the second end is arranged away from the aerofoil main wing. The span of the aerofoil flap is gradually reduced from the first end to the second end, and the chamfered portion is arranged on both side walls of the aerofoil flap close to the ends.

8. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 7, characterized in that: 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 beveling from the two sides of the first end to the two sides of the second end.

9. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in claim 8, characterized in that: The fifth distance is 1 / 10.

10. A force measuring wind tunnel test device with a jet-controlled airfoil as claimed in 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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