A narrow-band suction device and suction method for airfoils

Abstract

A narrow-band suction device and its suction method for airfoils, relating to the field of UAV aerodynamics, includes a suction panel, a gas delivery system, and a sealing structure. The sealing structure is disposed around the suction panel, which is fixed to the wing. The delivery system is fixed to the suction panel, which is also fixed to the leading, middle, or trailing edge of the upper surface of the wing. A parameter adjustment mechanism is provided to adjust the suction speed and direction. A flow rate controller adjusts the gas flow rate, and an angle adjuster connected to the wing changes the suction direction. This device can simulate the suction control conditions of the wing under different flight states, solving the problem of poor adaptability of traditional fixed suction devices. It provides reliable data support for optimizing the aerodynamic performance of UAV airfoils and is of great significance for improving the endurance and economy of UAVs.

Description

Technical Field

[0001] This invention relates to the field of aerodynamics technology for unmanned aerial vehicles (UAVs), and in particular to a narrow-band suction device and suction method for airfoils. Background Technology

[0002] Aerodynamic drag and lift are core factors affecting the endurance, range and operational efficiency of drones. Drag reduction and lift enhancement technologies are key to improving drone performance. The airflow state on the airfoil surface, such as boundary layer separation and turbulence development, directly affects the aerodynamic performance of drones.

[0003] Traditional methods for reducing drag in UAV airfoils often involve optimizing the shape or changing a single suction parameter (such as fixed position or velocity) for flow control, which makes it difficult to achieve significant aerodynamic drag reduction, especially for further improving the lift-to-drag ratio.

[0004] Therefore, providing a simple airfoil-shaped narrowband suction device and suction method for UAVs that can significantly improve the lift-to-drag ratio can solve the above-mentioned technical problems and has important engineering application value. Summary of the Invention

[0005] The purpose of this invention is to provide a narrow-band suction device and suction method for airfoils, which improves the lift-to-drag ratio performance of the airfoil by precisely adjusting the installation position of the narrow-band suction device, the gas flow rate, and the suction angle.

[0006] The present invention provides a narrow-band suction device for an airfoil, comprising a suction panel, a delivery system for absorbing gas, and a sealing structure. The sealing structure is disposed around the suction panel, the suction panel is fixed to the airfoil, and the delivery system is fixed to the suction panel.

[0007] Furthermore, the sealing structure is a sealant, which is applied around the suction panel.

[0008] Furthermore, the conveying system is a suction pump, with a suction port provided on the suction panel. One end of the suction pump is connected to the suction port, and the suction pump is fixedly connected to the suction panel.

[0009] Furthermore, the suction panel is fixed to the leading edge, middle, or trailing edge of the upper surface of the wing.

[0010] Furthermore, the suction panel is a strip structure, the width of the suction panel is 0.0167 to the chord length of the wing, and the length of the suction panel is the width of the wing span.

[0011] Furthermore, the ratio of the width of the suction port to the width of the suction panel is 0.4 to 0.8, and the ratio of the length of the suction port to the length of the suction panel is 0.8.

[0012] Furthermore, it also includes a parameter adjustment mechanism, which includes a flow rate controller for adjusting the gas flow rate and an angle adjuster for adjusting the angle between the suction port and the gas flow direction. The flow rate controller is fixed inside the suction panel, and the angle adjuster is fixedly connected to the wing.

[0013] Furthermore, it also includes a control module, which is electrically connected to the flow rate controller and the angle adjuster.

[0014] Furthermore, the flow rate adjustment range of the flow rate controller is 0.3. U ∞ ~0.7 U ∞ ,in, U ∞ The far-field velocity is defined as the angle range of 30° to 60°.

[0015] Furthermore, the flow rate controller includes a flow rate monitoring module for real-time monitoring of the suction velocity, and the angle adjuster includes an angle scale for real-time display of the angle between the suction port and the gas flow direction.

[0016] The flow rate monitoring module is electrically connected to the control module.

[0017] The present invention also provides a suction method, comprising the following steps:

[0018] S1: Set the wing's angle of attack to 10° and the far-field velocity U. ∞ , Reynolds number, select the target location to install the narrowband suction device;

[0019] S2: Adjust parameters, setting the gas flow rate to 0.3U using the flow rate controller and angle adjuster. ∞ 0.5U ∞ 0.7U ∞ The angles between the suction port and the gas flow direction are 30°, 45° and 60° respectively. Different working conditions are combined to form tests, and the resistance D, lift L and lift-to-drag ratio K are recorded under different working conditions.

[0020] S3: Calculate the drag coefficient, lift coefficient, and lift-to-drag ratio K according to the formula, where:

[0021] drag coefficient

[0022] Lift coefficient:

[0023] Boost-to-drag ratio:

[0024] Where ρ is the fluid density, and the unit is kg / m³. 3 S represents the reference area, which is the projected area of ​​the wing in the airflow direction, in meters (m²). 2 ;

[0025] S4: Collect and record experimental data;

[0026] S5: Analyze the data and determine the optimal parameter combination.

[0027] This invention discloses the following technical effects: This invention provides a narrow-band suction device and suction method for airfoils, which achieves suction position and velocity (0.3) through a parameter adjustment mechanism. U ∞ ~0.7 U ∞ The precise control of the suction speed and direction (30°~60°) changes the position of the suction panel on the upper surface of the wing. The parameter adjustment mechanism adjusts the suction speed and direction, the flow rate is adjusted by the flow rate controller, and the wing direction is changed by the angle adjuster connected to the wing, thereby changing the direction of the suction port, which can significantly improve the lift-to-drag ratio of the wing.

[0028] Secondly, a multi-condition test design is adopted, which covers the suction position, gas velocity and direction of the narrow-band suction device, and can comprehensively reflect the impact of parameter changes on aerodynamic performance.

[0029] Furthermore, the device of the present invention has a simple structure, is easy to change the suction position and adjust the parameters, has a wide range of applications, and can be extended to the aerodynamic performance testing of different types of UAV airfoils. It solves the problem of poor adaptability of traditional fixed parameter suction devices, provides reliable data support for the optimization of UAV airfoil aerodynamic performance, and is of great significance for improving the endurance and economy of UAVs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the wing structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the narrow-band suction device of the present invention installed on the leading edge of the wing;

[0033] Figure 3 This is a schematic diagram of the narrow-band suction device of the present invention installed in the middle of the wing;

[0034] Figure 4 This is a schematic diagram of the narrow-band suction device of the present invention installed on the trailing edge of an airfoil;

[0035] Figure 5 This invention is 0.5 U ∞ Comparison of upper surface pressure differential resistance distribution under 45° suction control;

[0036] Figure 6 This invention is 0.5 U ∞ Comparison of upper surface frictional resistance distribution under 45° suction control;

[0037] Wherein, 1. Wing; 2. Air intake panel; A is the angle of attack; B is the air intake direction; Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0040] like Figures 1-6 As shown, the present invention provides a narrow-band suction device, including a suction panel 2, a delivery system for absorbing gas, and a sealing structure. The sealing structure is a sealant, which is coated around the suction panel 2. The delivery system is a suction pump. A suction port is provided on the suction panel 2. One end of the suction pump is connected to the suction port. The suction pump is fixedly connected to the suction panel 2. The suction panel 2 is fixed on the wing 1.

[0041] In this embodiment, as Figure 2-4 As shown, the suction panel 2 is fixed to the leading edge, middle or trailing edge of the upper surface of the wing 1. The middle part refers to the position 0.5c (wing chord length c=0.15m) on the upper surface of the wing 1.

[0042] In this embodiment, the suction panel 2 is a strip structure. The width of the suction panel 2 is 0.0167 times the wing chord length, and the length is 0.3m of the spanwise length of the wing 1. The ratio of the width of the suction port to the width of the suction panel 2 is 0.4 to 0.8, and the ratio of the length of the suction port to the length of the suction panel 2 is 0.8.

[0043] In this embodiment, the wing 1 is model NACA0012, with a chord length of 0.15m, a span length of 0.3m, and a fixed angle of attack of 10°, that is, the width of the suction panel 2 is 0.0025m.

[0044] In this embodiment, a parameter adjustment mechanism and a control module are also included. The parameter adjustment mechanism includes a flow rate controller for adjusting the gas flow rate and an angle adjuster for adjusting the angle between the suction port and the gas flow direction. The flow rate controller is fixed inside the suction panel 2, and the angle adjuster is fixedly connected to the wing 1. The control module is electrically connected to the flow rate controller and the angle adjuster. The control module is used to control the operation and termination of the flow rate controller and the angle adjuster.

[0045] In this embodiment, the flow rate controller is selected from the Brooks Instrument SLA5850S ​​series; the angle adjuster is selected from the XR200 series electric rotary table to operate the wing 1 to change its position, thereby adjusting the direction of the suction port on it.

[0046] In this embodiment, the flow rate adjustment range of the flow rate controller is 0.3. U ∞ ~0.7

[0047] U ∞ ,in, U ∞ The far-field velocity is 7.7 m / s, and the angle range is 30° to 60°.

[0048] In this embodiment, the flow rate controller includes a flow rate monitoring module for real-time monitoring of the suction velocity, and the angle adjuster includes an angle scale for real-time display of the angle between the suction port and the gas flow direction.

[0049] The present invention also provides a suction method, comprising the following steps:

[0050] S1: Set the wing 1 to an angle of attack of 10° and a far-field flow velocity. U ∞ =7.7m / s, Reynolds number 77000, select the target location (leading edge, middle or trailing edge of the upper surface of wing 1) to install the narrow-band suction device;

[0051] S2: Adjust parameters by setting the gas flow rate to 0.3U using the flow rate controller and angle adjuster.∞ 0.5U ∞ 0.7U ∞ The angles between the suction port and the gas flow direction were 30°, 45°, and 60°, respectively, to form different working conditions for testing. The resistance D, lift L, and lift-to-drag ratio K were recorded under different working conditions.

[0052] S3: Calculate the drag coefficient, lift coefficient, and lift-to-drag ratio K according to the formula, where:

[0053] drag coefficient

[0054] Lift coefficient:

[0055] Boost-to-drag ratio:

[0056] Where ρ is the fluid density, and the unit is kg / m³. 3 S represents the reference area, which is the projected area of ​​wing 1 in the airflow direction, in meters. 2 ;

[0057] S4: Collect and record experimental data;

[0058] S5: Analyze the data and determine the optimal parameter combination.

[0059] Install the device following these steps:

[0060] Fix the NACA0012 airfoil to the test platform, ensuring an angle of attack of 10°;

[0061] According to the test requirements, the suction narrow strip device is installed at the target position (leading edge, middle or trailing edge), and the joint between the suction panel 2 and the wing 1 is treated with sealant.

[0062] Connect the parameter adjustment mechanism and calibrate the flow rate controller (error ≤ ±0.01U). ∞ ) and angle scale (error ≤ ±1°).

[0063] System settings and parameter calculations:

[0064] The test environment was set to far-field flow velocity. U ∞ =7.7m / s, Reynolds number 77000;

[0065] Pressure sensors and force sensors were used to measure the static pressure on the airfoil surface and the drag and lift it experienced, respectively.

[0066] Process the raw data according to the following formula:

[0067] Pressure coefficient:

[0068] Parameter description:

[0069] p: Local static pressure (Pa); p ∞ : Far-field static pressure (Pa); ρ: Fluid density (kg / m3); U ∞ Far-field velocity (m / s);

[0070] Data acquisition and analysis under different operating conditions:

[0071] Fixed suction velocity 0.5 U ∞ and the suction direction at 45° (e.g.) Figure 2 As shown in the figure), the comparison of aerodynamic drag and lift under suction control at three different positions is shown in Table 1.

[0072] Table 1

[0073]

[0074]

[0075] Observe the pressure drag distribution on the upper surface of wing 1 at different locations when it draws in air (e.g.) Figure 4 It can be observed that by drawing in air at different positions on wing 1, the pressure drag at the trailing edge of wing 1 is reduced to varying degrees. Among them, when air is drawn in at position 0.5c on wing 1, the pressure drag at the trailing edge of wing 1 is reduced the most, and the drag reduction effect is the best.

[0076] Observe the distribution of frictional resistance on the upper surface of wing 1 when it draws in air at different positions (e.g.) Figure 5 It was found that when the airflow was drawn in at the leading edge of wing 1, the frictional resistance on wing 1 increased at the leading edge of wing 1; when the airflow was drawn in at position 0.5c of wing 1, the frictional resistance on the leading edge of wing 1 decreased significantly, while the frictional resistance near the airflow inlet increased slightly; when the airflow was drawn in at the trailing edge of wing 1, the frictional resistance on the leading edge of wing 1 decreased.

[0077] By drawing air in through an inlet at 0.5c on wing 1 at a 45° angle to the flow direction, the drag and lift experienced by wing 1 under different airflow velocities were compared; the results are shown in Table 2.

[0078] U ∞ It is 7.7 m / s, corresponding to 0.3 U ∞ The suction velocity is 2.31 m / s, and so on.

[0079] Table 2

[0080]

[0081] The table clearly shows that after the suction port is installed, the drag decreases and the lift increases compared to the case without suction. At the same time, as the suction speed increases, the drag on wing 1 decreases and the lift increases, and the lift-to-drag ratio also improves. It can be concluded that when the suction port at 0.5c on wing 1 draws water at a 45° angle, the drag reduction effect of wing 1 improves as the speed increases.

[0082] At the 0.5c intake port of wing 1, with a flow rate of 0.7U... ∞ The drag reduction simulation was performed at speeds of 30°, 45°, and 60°. The drag and lift of the wing 1 under different suction directions were compared, and the results are shown in Table 3.

[0083] Table 3

[0084]

[0085] As shown in the table, as the suction angle increases, the drag of wing 1 decreases, the lift increases, and the lift-to-drag ratio of wing 1 increases; when suction is directed towards 60°, the lift-to-drag ratio reaches 23.12, and the lift-to-drag ratio improvement rate reaches 116.1%.

[0086] By comparing the lift-to-drag ratio improvement rates under different operating conditions (relative to the no-suction state), the optimal operating condition was determined: 0.7U is drawn in at a 60° angle from 0.5c on wing 1. ∞ At high airflow speeds, the lift-to-drag ratio improvement rate reaches 116.1%.

[0087] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0088] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A narrow-band suction device for airfoils, characterized in that, The device includes a suction panel (2), a gas delivery system for absorbing gas, and a sealing structure. The sealing structure is disposed around the suction panel (2). The suction panel (2) is fixed to the wing (1). The delivery system is fixed to the suction panel (2). The delivery system includes a suction pump. A suction port is provided on the suction panel (2). One end of the suction pump is connected to the suction port. The suction pump is fixedly connected to the suction panel (2). The suction panel (2) is fixed to the leading edge, middle, or trailing edge of the upper surface of the wing (1). The ratio of the width of the suction panel (2) to the chord length of the wing (1) is 0.0167. The length of the suction panel (2) is the width of the wingspan of the wing (1). It also includes a parameter adjustment mechanism, which includes a flow rate controller for adjusting the gas flow rate and an angle adjuster for adjusting the angle between the suction port and the gas flow direction. The flow rate controller is fixed inside the suction panel (2), and the angle adjuster is fixedly connected to the wing (1).

2. The narrow-band suction device for an airfoil according to claim 1, characterized in that, The sealing structure is a sealant, which is applied around the suction panel (2).

3. A narrow-band suction device for an airfoil according to claim 1, characterized in that, The ratio of the width of the suction port to the width of the suction panel (2) is 0.4 to 0.8, and the ratio of the length of the suction port to the length of the suction panel (2) is 0.

8.

4. A narrow-band suction device for an airfoil according to claim 1, characterized in that, The flow rate adjustment range of the flow rate controller is 0.3U. ∞ ~0.7U ∞ , among which, U ∞ The far-field velocity has an angle range of 30° to 60°.

5. A narrow-band suction device for an airfoil according to claim 4, characterized in that, The flow rate controller includes a flow rate monitoring module for real-time monitoring of the suction velocity, and the angle adjuster includes an angle scale for real-time display of the angle between the suction port and the gas flow direction.

6. A suction method for a narrow-band suction device for an airfoil according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Set the wing (1) to an angle of attack of 10° and a far-field velocity U ∞ Reynolds number, select the target location to install the narrowband suction device; S2: Adjust parameters by setting the gas flow rate to 0.3U using the flow rate controller and angle adjuster. ∞ 0.5U ∞ 0.7U ∞ The angles between the suction port and the gas flow direction were 30°, 45° and 60°, respectively, and different working conditions were formed for testing. The resistance D, lift L and lift-to-drag ratio K were recorded under different working conditions. S3: Calculate the drag coefficient, lift coefficient, and lift-to-drag ratio K according to the formula, where: Drag coefficient: Lift coefficient: Boost-to-drag ratio: Where ρ is the fluid density, and the unit is kg / m³. 3 S is the projected area of ​​the wing (1) in the airflow direction, in m². 2 ; S4: Collect and record experimental data; S5: Analyze the data and determine the optimal parameter combination.

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