Active simulation wind tunnel test method for wake flow field of oiling machine

Abstract

The invention belongs to the field of low-speed wind tunnel tests, and discloses an active simulation wind tunnel test method for a wake flow field of an oiling machine, and the method comprises the following steps: 1, determining an initial trailing vortex circular rector and a trailing vortex initial vortex nucleus distance in a model; step 2, installing an active simulation generation device for the wake flow field of the oiling machine; 3, a flow field calibration mechanism is installed; step 4, starting a wind tunnel and an oiling machine wake flow active simulation generation device, starting a hot-wire probe to carry out acquisition, and measuring and calculating a flow field velocity circulation; 5, calculating a rotating speed gain coefficient to simulate a target refueling machine wake flow field, and calculating to obtain a rotating speed control gain coefficient K according to the circulation data; starting the wind tunnel to a specified wind speed, controlling the rotating speed of the motor to be stabilized to a corrected rotating speed N, and generating a target refueling machine wake flow field in the test area. The oiling machine wake flow field can be simulated in the wind tunnel environment, and the problems that wake flow field simulation is prone to distortion and sensor arrangement cannot be carried out due to the fact that wind tunnel size is limited in an existing oiling machine wake flow field direct simulation test are solved.

Description

Technical Field

[0001] The present application relates to a wind tunnel test method for actively simulating the wake field of a refueling machine, and belongs to the field of low-speed wind tunnel tests. Background Art

[0002] Aerial refueling simulation wind tunnel test technology is an important research method for the design and evaluation of aerial refueling safety. In particular, the wake of the tanker during aerial refueling will affect the safety of refueling docking. At present, there is a lack of effective calculation methods for these complex aerodynamic interferences. Wind tunnel tests can be used as an effective evaluation method.

[0003] The wake field of a tanker is mainly composed of a pair of vortices with opposite rotation directions rolled up at the wing tip by the airflow flowing through the wing, i.e., a pair of wingtip vortices. The radius of the wingtip vortex is related to the wingspan of the model. For example, a 40-meter wingspan corresponds to a wingtip vortex radius of about 2 meters. However, due to the limitation of the size of the wind tunnel, a large-wingspan model cannot be placed, and it is also impossible to simulate large-scale wingtip vortices. In the past, wind tunnel tests mainly used direct simulation methods, that is, passive simulation, to simulate the wake of a tanker. That is, a scaled-down model of the aircraft is placed in the wind tunnel, and the airflow flows over the surface of the model to generate a tanker wake field at its rear, i.e., a pair of wingtip vortices. This method is simple, but due to the limitation of the size of the wind tunnel, the model is scaled too large, which brings about the problem of distortion of the wake field simulation. At the same time, when it is applied to the evaluation of the aerodynamic characteristics of the receiving aircraft, it is easy to encounter problems such as the size of the receiving aircraft being too small to arrange sensors, which seriously restricts the application of wind tunnel tests in scenarios such as evaluating the aerodynamics of tankers and receivers, and it is easy to cause uneconomical phenomena such as only occupying large low-speed wind tunnels for research. Summary of the invention

[0004] To solve the above problems, the present invention adopts a method of actively simulating the wake field of the tanker, directly setting a pair of vortex structures with opposite rotation directions to generate a pair of vortices with opposite rotation directions, which are similar in shape to the wingtip vortex, and their vortex radius is similar to the scale of the rotating blade of the device. This effectively solves the problems that the original passive simulation method is limited by the size of the wind tunnel and cannot accommodate large wingspan models, and the passive wake field simulation is prone to distortion and cannot be arranged for sensors.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows: a wind tunnel test method for actively simulating the wake flow field of a refueling machine, comprising the following steps: Step 1: Determine the wingspan, weight, and flight speed of the tanker according to the tanker model, and use the Kutta-Jokovsky theorem to determine the initial tail vortex circulation, the initial vortex core spacing, and the initial vortex core radius in the mathematical model of the tanker wake field. r c0 ; Step 2: Install the active simulation device for the wake field of the refueling machine; the device consists of two sets of independent blade rotation mechanisms, one at the entrance of the wind tunnel test section and the other at the symmetric plane of the wind tunnel center.b The blade rotation mechanism is arranged at the 0 / 2 position, and the blade rotation mechanism includes a blade, and the radius of the blade is selected from the initial vortex core radius r c0 The two blade rotating mechanisms are horizontally spaced one time apart from the initial vortex core spacing of the tail vortex and are at the same height. h / 2,h is the height of the wind tunnel test section; Step 3: Install the flow field calibration mechanism: The flow field calibration mechanism is fixedly installed at the bottom of the wind tunnel downstream of the active simulation device for the tail flow field of the refueling machine; adjust the position of the hot wire probe of the flow field calibration mechanism so that the hot wire probe is located at h / 2 fixed; Step 4: Start the wind tunnel and the active simulation device for the tanker wake, measure the flow field and calculate the flow field velocity circulation; start the wind tunnel, stabilize for t seconds after the wind tunnel reaches the specified wind speed, and start the active simulation device for the tanker wake at a fixed speed. n After the speed stabilizes for t seconds, the hot wire probe flow field calibration mechanism is started, and the hot wire probe collects data to obtain vertical velocity data, and then passes through the track to b The hot wire probe is moved at 0 / 12 intervals and data collection is repeated until the velocity measurement of all measuring points within the range of twice the initial vortex core spacing of the tail vortex is completed; the velocity data of the measuring points obtained by the measurement v i The tail vortex circulation of the wind tunnel flow field is calculated; Step 5, calculating the speed control gain coefficient and simulating the target tanker wake field; calculating the speed control gain coefficient K according to the initial wake vortex circulation obtained in step 1 and the wind tunnel flow field wake vortex circulation obtained in step 4; (1) (2) In the formula N ——corrected speed, unit: r / s; n ——Fixed speed, unit: r / s; ——Initial tail vortex circulation, unit: m 2 / s; ——wind tunnel flow field tail vortex circulation, unit: m 2 / s; Start the wind tunnel to the specified wind speed and control the motor speed to stabilize to the corrected speed N , the target tanker wake field is generated in the test area.

[0006] Furthermore, the Kutta-Jokovsky theorem is as follows: (3) (4) (5) Where: g ——Gravity acceleration, unit: m / s 2 ; b 0——the distance between the initial vortex cores of the trailing vortex, in m; ρ ——Air density at flight altitude, in kg / m 3 ; b ——wingspan, in m; M ——weight of the tanker, in kg; V ——flight speed, m / s; r c0 ——Initial vortex core radius, in m.

[0007] Furthermore, the acquisition frequency of the hot wire probe is 200 Hz, and the acquisition time is 1 second.

[0008] Furthermore, the blade rotation mechanism includes a flange support base, a motor transmission support rod, a motor, a transmission shaft, a hub, blades, a fairing, bearings, a coupling and a bearing seat; the lower end surface of the flange support base is fixedly mounted on the cave wall at the bottom of the wind tunnel, the upper end surface of the flange support base is connected to the lower end surface of the motor transmission support rod, the upper end surface of the motor transmission support rod is connected to the motor transmission base, the motor is fixedly mounted on the motor transmission base, the motor is connected to the hub through a coupling and a transmission shaft, the transmission shaft is fixed to the motor transmission base through bearings and bearing seat supports; the blades are installed on the hub; a fairing is arranged at the front end of the hub.

[0009] Furthermore, the flow field calibration mechanism includes a calibration base, an adapter, a calibration pillar, a hot wire probe, a track and a slider; the upper surface of the adapter is connected to the calibration pillar, the hot wire probe is fixed on the upper end of the calibration pillar, and a slider is provided on the lower surface of the adapter; the lower end surface of the calibration base is fixedly mounted on the wall of the bottom of the wind tunnel, the upper end surface of the calibration base is provided with a track, and the slider is slidably connected to the track to realize the lateral movement of the hot wire probe.

[0010] Furthermore, the t seconds is 3 seconds.

[0011] Furthermore, the speed of all measuring points within the range of the lateral twice the initial vortex core spacing of the tail vortex is obtained, and a total of 25 measuring point speed data are obtained. v i , i =-12~12; point data obtained by measurementv i The calculated vortex circulation in the wind tunnel flow field : (6) (7) (8) In the formula i ——The number of measuring point positions, which is an integer; v i ——The speed corresponding to different measurement positions, in m / s; v ——The maximum speed of the left and right vortices, in m / s; x v --speed v The distance from the corresponding position to the center plane of the wind tunnel, in m; r ——The horizontal distance between the maximum speed position of the left and right tail vortices and the center point of the blade, in meters; The speed of 25 measuring points is calculated by formula (6): v i Maximum speed in data v , and the speed v The distance from the corresponding position to the center plane of the wind tunnel and the distance calculated in step 1 b Substitute 0 into formula (7) to obtain the maximum speed v The horizontal distance between the position and the center point of the blade is then calculated by formula (8) to obtain the value of the tail vortex circulation of the calibrated flow field.

[0012] Beneficial effects of the present application: The test method of the present application uses two sets of independent blade rotation mechanisms with opposite rotation directions to generate simulated wingtip vortices, simulates the wake field of the tanker in a wind tunnel environment, and can complete the wind tunnel test of the wake field of the tanker without putting a large-scale wing model into the wind tunnel. It has the advantages of strong simulation ability of the wake field of the tanker, wide adjustment range, and good simulation accuracy; the present invention has strong engineering practicality, and can provide a reliable test method for evaluating the aerodynamic characteristics and dynamic response laws of various types of receiving aircraft under the interference of the wake of the tanker, and effectively support the development of advanced aerial refueling technology. The present application not only solves the problem of small wingtip vortex size, but also uses the method of the present application to more conveniently change parameters such as vortex scale and intensity. Compared with passive simulation to replace different models to simulate wingtip vortices, it has the advantage of being more economical and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a simplified cross-sectional diagram of the aircraft wake field; Figure 2This is a schematic diagram of the active simulation device for the wake field of the tanker; Figure 3 Schematic diagram of the flow field calibration mechanism.

[0014] In the figure: 1- fairing, 2- hub, 3- blade, 4- bearing, 5- transmission shaft, 6- bearing seat, 7- coupling, 8- motor, 9- motor transmission base, 10- motor transmission support rod, 11- flange support base, 12- cave wall, 13- hot wire probe, 14- slider, 15- track, 16- adapter, 17- calibration support, 18- calibration base. DETAILED DESCRIPTION

[0015] The present application will be described in detail below in conjunction with the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of the structure and technical common knowledge is omitted to avoid unnecessary confusion of the concept of the present application.

[0016] Embodiment 1: Combination Figure 1-3 A wind tunnel test method for actively simulating the wake field of a refueling machine comprises the following steps: Step 1: Determine the wingspan, weight, and flight speed of the tanker according to the tanker model, and use the Kutta-Jokovsky theorem to determine the initial tail vortex circulation, the initial vortex core spacing, and the initial vortex core radius in the mathematical model of the tanker wake field. r c0 ; Step 2: Install the active simulation device for the wake field of the refueling machine; the device consists of two sets of independent blade rotation mechanisms, one at the entrance of the wind tunnel test section and the other at the symmetric plane of the wind tunnel center. b The blade rotation mechanism is arranged at the 0 / 2 position, and the blade rotation mechanism includes blade 3, and the radius of the blade 3 is selected from the initial vortex core radius r c0 The two blade rotating mechanisms are horizontally spaced one time apart from the initial vortex core spacing of the tail vortex and are at the same height. h / 2, h is the height of the wind tunnel test section; Step 3: Install the flow field calibration mechanism: The flow field calibration mechanism is fixedly installed at the bottom of the wind tunnel downstream of the active simulation generating device of the tail flow field of the tanker; adjust the position of the hot wire probe 13 of the flow field calibration mechanism so that the hot wire probe 13 is located at h / 2 fixed; Step 4: Start the wind tunnel and the active simulation device for the tanker wake, measure the flow field and calculate the flow field velocity circulation; start the wind tunnel, stabilize for t seconds after the wind tunnel reaches the specified wind speed, and start the active simulation device for the tanker wake at a fixed speed. nAfter the rotation speed stabilizes for t seconds, the hot wire probe flow field calibration mechanism is started, and the hot wire probe 13 collects data to obtain vertical velocity data, and then passes through the track 15 to b The hot wire probe 13 is moved at 0 / 12 intervals, and data collection is repeated until the velocity measurement of all measuring points within the range of twice the initial vortex core spacing of the tail vortex is completed; the velocity data of the measuring points obtained by the measurement v i The tail vortex circulation of the wind tunnel flow field is calculated; Step 5, calculating the speed control gain coefficient and simulating the target tanker wake field; calculating the speed control gain coefficient K according to the initial wake vortex circulation obtained in step 1 and the wind tunnel flow field wake vortex circulation obtained in step 4; (1) (2) In the formula N ——corrected speed, unit: r / s; n ——Fixed speed, unit: r / s; ——Initial tail vortex circulation, unit: m 2 / s; ——wind tunnel flow field tail vortex circulation, unit: m 2 / s; Start the wind tunnel to the specified wind speed and control the motor speed to stabilize to the corrected speed N , the target tanker wake field is generated in the test area.

[0017] Furthermore, the Kutta-Jokovsky theorem is as follows: (3) (4) (5) Where: g ——Gravity acceleration, unit: m / s 2 ; b 0——the distance between the initial vortex cores of the trailing vortex, in m; ρ ——Air density at flight altitude, in kg / m 3 ; b ——wingspan, in m; M ——weight of the tanker, in kg; V ——flight speed, m / s; r c0 ——Initial vortex core radius, in m.

[0018] Furthermore, the acquisition frequency of the hot wire probe is 200 Hz, and the acquisition time is 1 second.

[0019] Furthermore, the blade rotation mechanism includes a flange support base 11, a motor transmission support rod 10, a motor 8, a transmission shaft 5, a hub 2, a blade 3, a fairing 1, a bearing 4, a coupling 7 and a bearing seat 6; the lower end face of the flange support base 11 is fixedly mounted on the cave wall 12 at the bottom of the wind tunnel, the upper end face of the flange support base 11 is connected to the lower end face of the motor transmission support rod 10, the upper end face of the motor transmission support rod 10 is connected to the motor transmission base 9, the motor 8 is fixedly mounted on the motor transmission base 9, the motor 8 is connected to the hub 2 through the coupling 7 and the transmission shaft 5, the transmission shaft 5 is supported and fixed on the motor transmission base 9 through the bearing 4 and the bearing seat 6; the blade 3 is installed on the hub 2; and the fairing 1 is arranged at the front end of the hub 2.

[0020] Furthermore, the flow field calibration mechanism includes a calibration base 18, an adapter seat 16, a calibration pillar 17, a hot-wire probe 13, a track 15 and a slider 14; the upper surface of the adapter seat 16 is connected to the calibration pillar 17, the hot-wire probe 13 is fixed on the upper end of the calibration pillar 17, and the lower surface of the adapter seat 16 is provided with a slider 14; the lower end surface of the calibration base 18 is fixedly installed on the cave wall 12 at the bottom of the wind tunnel, the upper end surface of the calibration base 18 is provided with a track 15, and the slider 14 is slidably connected to the track 15 to realize the lateral movement of the hot-wire probe 13.

[0021] Furthermore, the t seconds is 3 seconds.

[0022] Furthermore, the velocity data of all points within the range of the lateral twice the initial vortex core spacing of the tail vortex are obtained, and a total of 25 point velocity data are obtained. v i , i =-12~12; point data obtained by measurement v i The calculated vortex circulation in the wind tunnel flow field : (6) (7) (8) In the formula i ——The number of measuring point positions, which is an integer; v i ——The speed corresponding to different measurement positions, in m / s; v——The maximum speed of the left and right vortices, in m / s; x v --speed v The distance from the corresponding position to the center plane of the wind tunnel, in meters; r ——The horizontal distance between the maximum speed position of the left and right tail vortices and the center point of the blade, in meters; The 25 point velocities are calculated by formula (6): v i Maximum speed in data v , and the speed v The distance from the corresponding position to the center plane of the wind tunnel and the distance calculated in step 1 b Substitute 0 into formula (7) to obtain the maximum speed v The horizontal distance between the position and the center point of the blade is then calculated using formula (8) to obtain the value of the tail vortex circulation of the calibrated flow field.

[0023] The above embodiments are merely illustrative of the principles and effects of the present application, and are not intended to limit the present application. Anything within the technical concept disclosed in the present application, and any simple replacement or change based on the technical solution of the present application, shall fall within the protection scope of the present application.

Claims

1. A wind tunnel test method for active simulation of the wake field of a refueling machine, characterized in that: The following steps are included: Step 1: Determine the wingspan, weight, and flight speed of the tanker according to the tanker model, and use the Kutta-Jokovsky theorem to determine the initial tail vortex circulation, the initial vortex core spacing, and the initial vortex core radius in the mathematical model of the tanker wake field. r c0 ; Step 2: Install the active simulation device for the wake field of the refueling machine; The device consists of two independent blade rotation mechanisms, one at the entrance of the wind tunnel test section and the other at the symmetric plane of the wind tunnel center. b A blade rotation mechanism is arranged at the 0 / 2 position, the blade rotation mechanism comprising a blade (3), the radius of the blade (3) being selected from the radius of the initial vortex core r c0 The two blade rotating mechanisms are horizontally spaced one time apart from the initial vortex core spacing of the tail vortex and are at the same height. h / 2, h is the height of the wind tunnel test section; Step 3: Install the flow field calibration mechanism: The flow field calibration mechanism is fixedly installed at the bottom of the wind tunnel downstream of the active simulation generating device of the tail flow field of the tanker; Adjust the position of the hot wire probe (13) of the flow field calibration mechanism so that the hot wire probe (13) is located at h / 2 fixed; Step 4: Start the wind tunnel and the active simulation device for the tanker wake, measure the flow field and calculate the flow field velocity circulation; start the wind tunnel, stabilize for t seconds after the wind tunnel reaches the specified wind speed, and start the active simulation device for the tanker wake at a fixed speed. n The hot wire probe (13) is rotated, and after the rotation speed is stabilized for t seconds, the hot wire probe flow field calibration mechanism is started, and the hot wire probe (13) collects data to obtain vertical velocity data, and then passes through the track (15) to b The hot wire probe (13) is moved at 0 / 12 intervals, and data collection is repeated until the velocity measurement of all measuring points within the range of twice the initial vortex core spacing of the tail vortex is completed; the velocity data of the measuring points obtained by the measurement v i The tail vortex circulation of the wind tunnel flow field is calculated; Step 5, calculating the speed control gain coefficient and simulating the target tanker wake field; calculating the speed control gain coefficient K according to the initial wake vortex circulation obtained in step 1 and the wind tunnel flow field wake vortex circulation obtained in step 4; （1） （2） In the formula N ——corrected speed, unit: r / s; n ——Fixed speed, unit: r / s; ——Initial tail vortex circulation, unit: m 2 / s; ——wind tunnel flow field tail vortex circulation, unit: m 2 / s; Start the wind tunnel to the specified wind speed and control the motor speed to stabilize to the corrected speed N , the target tanker wake field is generated in the test area.

2. The active simulation wind tunnel test method for the wake field of a refueling machine according to claim 1 is characterized in that: The Kutta-Joukowski theorem is as follows: （3） （4） （5） Where: g ——Gravity acceleration, unit: m / s 2 ; b 0——the distance between the initial vortex cores of the trailing vortex, in m; ρ ——Air density at flight altitude, in kg / m 3 ; b ——wingspan, in m; M ——weight of the tanker, in kg; V ——flight speed, m / s; r c0 ——Initial vortex core radius, in m.

3. The active simulation wind tunnel test method for the wake field of a refueling machine according to claim 2 is characterized in that: The acquisition frequency of the hot wire probe is 200 Hz, and the acquisition time is 1 second.

4. The active simulation wind tunnel test method for the wake field of a refueling machine according to claim 3 is characterized in that: The blade rotation mechanism comprises a flange support base (11), a motor transmission support rod (10), a motor (8), a transmission shaft (5), a propeller hub (2), a blade (3), a fairing (1), a bearing (4), a coupling (7) and a bearing seat (6); the lower end surface of the flange support base (11) is fixedly mounted on a hole wall (12) at the bottom of a wind tunnel, the upper end surface of the flange support base (11) is connected to the lower end surface of the motor transmission support rod (10), the upper end surface of the motor transmission support rod (10) is connected to the motor transmission base (9), the motor (8) is fixedly mounted on the motor transmission base (9), the motor (8) is connected to the propeller hub (2) via the coupling (7) and the transmission shaft (5), the transmission shaft (5) is supported and fixed on the motor transmission base (9) via the bearing (4) and the bearing seat (6); the blade (3) is mounted on the propeller hub (2); and the front section of the propeller hub (2) is provided with a fairing (1).

5. The active simulation wind tunnel test method for the wake field of a refueling machine according to claim 2 is characterized in that: The flow field calibration mechanism comprises a calibration base (18), an adapter base (16), a calibration support (17), a hot-wire probe (13), a track (15) and a slider (14); the upper surface of the adapter base (16) is connected to the calibration support (17), the hot-wire probe (13) is fixed to the upper end of the calibration support (17), and the lower surface of the adapter base (16) is provided with a slider (14); the lower end surface of the calibration base (18) is fixedly mounted on a hole wall (12) at the bottom of the wind tunnel, the upper end surface of the calibration base (18) is provided with a track (15), and the slider (14) is slidably connected to the track (15) to achieve lateral movement of the hot-wire probe (13).

6. The active simulation wind tunnel test method for the wake field of a refueling machine according to claim 1 is characterized in that: The t is 3 seconds.

7. The active simulation wind tunnel test method for the wake field of a refueling machine according to claim 1 is characterized in that: The velocity data of all points within the range of the lateral double tail vortex initial vortex core spacing are obtained for a total of 25 measurement points. v i , i =-12~12; point data obtained by measurement v i The calculated vortex circulation in the wind tunnel flow field : （6） （7） （8） In the formula i ——The number of measuring point positions, which is an integer; v i ——The speed corresponding to different measurement positions, in m / s; v ——The maximum speed of the left and right vortices, in m / s; x v --speed v The distance from the corresponding position to the center plane of the wind tunnel, in meters; r ——The horizontal distance between the maximum speed position of the left and right tail vortices and the center point of the blade, in meters; The speed of 25 measuring points is calculated by formula (6): v i Maximum speed in data v , and the speed v The distance from the corresponding position to the center plane of the wind tunnel and the distance calculated in step 1 b Substitute 0 into formula (7) to obtain the maximum speed v The horizontal distance between the position and the center point of the blade is then calculated by formula (8) to obtain the value of the tail vortex circulation of the calibrated flow field.

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