A synchronous measurement device and method for rotor wind-sand flow field

Abstract

The invention discloses a synchronous measurement device and a measurement method for a rotor wind-sand flow field, and relates to the technical field of wind-sand flow field measurement technology and its auxiliary device. The device comprises an ultrasonic anemometer, a sand transport rate measuring instrument, a dust monitor, a black-and-white marker, and a camera arranged directly below a rotor. The ground directly below the rotor is taken as a measurement center, a polar coordinate system is constructed with the measurement center as a pole, and the length of a single rotor is R. Six groups of ultrasonic anemometers are provided; two groups of sand transport rate measuring instruments are provided; an angle between a center line of the field of view of the camera and the ground is θ, and θ is an integer multiple of 5 between 5 and 50°; an inclined angle between a plane where the black-and-white marker is located and the ground is 90°-θ, and the black-and-white marker is within the range of the center line of the field of view of the camera, and the center line of the field of view of the camera is perpendicular to the plane where the black-and-white marker is located; and four groups of dust monitors are provided.

Description

Technical Field

[0001] The invention relates to the field of wind-sand flow field measurement technology and auxiliary device technology, and in particular to a synchronous measurement device and method for a rotor wind-sand flow field. Background Art

[0002] When a helicopter takes off, lands or flies at low altitude, the airflow generated by the rotating wings will roll up fine particles on the ground (such as dust, gravel, etc.), forming a dust cloud around the helicopter. This causes the helicopter's view in front to be blurred or completely blocked. This phenomenon is called "sand blindness", which causes visual impairment to the pilot and poses a potential flight safety hazard.

[0003] Wind speed, surface sand transport rate, airborne dust concentration and visual visibility are key research factors in studying the "sand blindness" phenomenon. The ultrasonic anemometer (CSAT3B) can measure wind speed in three directions; the surface sand transport rate can be measured using a sand transport rate meter (SandFlow4, SF4 for short), which can measure the mass of surface sand per unit area per unit time; the airborne dust concentration can be measured using a dust meter (Dusttrack8530), which can measure the mass of sand per unit volume; visibility measurement can be based on the contrast analysis of black and white markers.

[0004] However, unlike the natural flow of wind and sand, the helicopter's near-ground interference flow field has complex three-dimensional characteristics. The fixed position, fixed height and fixed direction of the instrument will affect the measurement of the three-dimensional complex flow field. In the existing technology, in order to accurately measure, each instrument often needs to be placed in different positions, heights and directions for multiple measurements. However, these measurement data are affected by the time factor because of the order of measurement. It is well known that in the wind and sand flow field, the wind and sand conditions at different time points are different. It can be seen that the time factor seriously affects the measurement accuracy. Summary of the invention

[0005] In view of the above problems in the prior art, the present invention provides a synchronous measurement device and method for a rotor wind-sand flow field, so as to solve the problem in the prior art that the time factor affects the measurement accuracy due to the order of different data measurements.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A synchronous measurement device for a rotor wind-sand flow field, comprising an ultrasonic anemometer, a sand transport rate measuring instrument, a dust meter, a black and white marker, and a camera arranged directly below the rotor; the ground directly below the rotor is taken as the measurement center, a polar coordinate system is constructed with the measurement center as the pole, and the length of the single rotor is R; the ultrasonic anemometer is provided with 6 groups, and the 6 groups of ultrasonic anemometers are respectively arranged at different polar diameters with polar angles of 45°, 90°, 135°, 225°, 270°, and 315°, and the polar diameter range of the ultrasonic anemometer is 1R~4.5R; the sand transport rate measuring instrument is provided with two groups, and the two groups of sand transport rate measuring instruments are provided with a polar coordinate system. The instruments are located at different polar diameters of the same polar angle, and the polar diameter range of the sediment transport rate measuring instrument is 1.5R~4.5R, and the distance between the two sediment transport rate measuring instruments is greater than 1R; the angle between the center line of the field of view of the camera and the ground is θ, and θ is an integer multiple of 5 between 5~50°; the inclination angle between the plane where the black and white markers are located and the ground is 90°-θ, and the black and white markers are within the range of the center line of the field of view of the camera, and the center line of the field of view of the camera is perpendicular to the plane where the black and white markers are located; the dust monitor is provided with 4 groups, and the measuring points of the 4 groups of dust monitors are arranged on the symmetric line of the center line of the field of view of the camera.

[0008] Preferably, the polar diameters of the six groups of ultrasonic anemometers increase in the polar angle sequence of 90°, 135°, 225°, 270°, 315°, and 45°.

[0009] Preferably, the polar angle and polar diameter parameters of the two sets of sediment transport rate measuring instruments are (0 degrees, 2.5R) and (0 degrees, 3.5R), respectively.

[0010] Preferably, the ultrasonic anemometer is connected to a support I via a connecting piece I, and the support I is composed of a rectangular base plate with side ears and a square tube with circular through holes, and the square tube is vertically fixed in the center of the rectangular base plate; the connecting piece I comprises two parts, a vertical plate and a horizontal sleeve, and the connecting piece I is fixedly connected to the square tube of the support I via the through hole on the vertical plate of the connecting piece I, and the mounting sleeve of the ultrasonic anemometer is sleeved outside the horizontal sleeve.

[0011] Furthermore, the dust monitor is connected to a support I through a connecting member II, the connecting member II comprises two parts, a vertical plate and a horizontal plate, which are vertically connected. The connecting member II is fixedly connected to the square tube of the support I through the through hole on the vertical plate of the connecting member II, and the dust monitor is connected to the horizontal plate of the connecting member II by bolts.

[0012] Furthermore, both ends of the sediment transport rate measuring instrument are respectively fixed on a support II through a connecting piece II, and the support II is composed of a rectangular base plate and a square tube with a circular through hole, and the square tube is vertically fixed in the center of the rectangular base plate; the connecting piece II is fixedly connected to the square tube of the support II through the through hole on the vertical plate of the connecting piece II, and the two ends of the sediment transport rate measuring instrument are connected to the horizontal plate of the connecting piece II by bolts.

[0013] Preferably, the black and white marker is fixed on a portable variable-angle sand-proof tilt platform, and the portable variable-angle sand-proof tilt platform consists of a tilt cover plate, a tilt base and a tilt support plate.

[0014] The synchronous measurement method of the rotor wind-sand flow field using any one of the synchronous measurement devices described above comprises the following steps:

[0015] (1) Before the rotors rotate, turn on all instruments and put them in working order, and calibrate the instrument time;

[0016] (2) Control the rotation of the rotor. During the rotation process, two sand transport rate measuring instruments monitor the sand transport rate near the measurement position in real time, the dust meter monitors the dust concentration near the measurement port in real time, and the ultrasonic anemometer monitors the three-dimensional wind speed near the measurement point in real time. The camera focuses on the center of the tilt cover plate and shoots video in real time.

[0017] (3) After the rotor stops, the data of each instrument and camera are exported and the corresponding time of the data is unified. Synchronous measurement is achieved by taking the intersection of the Beijing time of each instrument, calculating the field of view concentration and visibility, and realizing quantitative analysis of visibility and concentration, as well as correlation analysis between concentration and sediment transport rate, and between sediment transport rate and wind speed.

[0018] In summary, compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] 1. The present invention realizes the synchronous measurement of multiple elements of the rotor wind-sand two-phase flow field, and provides an experimental means for quantitatively describing the relationship between wind speed, surface sand transport rate, air dust concentration and field visibility. Time "synchronization" is the key to the entire technology, which lays the foundation for the establishment of quantitative relationships between various elements.

[0020] 2. The sand-proof effect of the instruments used in the present invention is relatively good, especially the specially designed portable variable-angle sand-proof tilt table, which is not afraid of the influence of wind and sand on the mechanical structure and is easy to store and carry;

[0021] 3. The bracket designed in the present invention not only has a sand-proof effect, but also can adjust the installation height of the instrument. By changing the bracket placement and the instrument installation height, most of the measurement requirements of the wind-sand two-phase experiment for wind speed, surface sand transport rate, air dust concentration and field visibility are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A stereogram of the instrument installation of the synchronous measurement device for the rotor wind-sand flow field provided in Example 1;

[0023] Figure 2 A top view of the instrument installation of the synchronous measurement device for the rotor wind-sand flow field provided in Example 1;

[0024] Figure 3 The front view of the instrument installation of the synchronous measurement device for the rotor wind-sand flow field provided in Example 1, wherein θ is the inclination angle between the plane where the black and white markers are located and the ground;

[0025] Figure 4 This is a schematic diagram of the installation of an ultrasonic anemometer;

[0026] Figure 5 It is a structural schematic diagram of the connecting member 1;

[0027] Figure 6 This is the installation diagram of the dust monitor;

[0028] Figure 7 is a schematic diagram of the structure of the connector II;

[0029] Figure 8 This is the installation diagram of the sediment transport rate measuring instrument;

[0030] Fig. 9 A diagram showing the use of a portable variable-angle anti-sand tilting table with black and white markings attached;

[0031] Fig.10 It is a schematic diagram of the bottom surface of the portable variable-angle sand-proof tilt table in the storage state;

[0032] Fig.11 It is a schematic diagram of the top surface of the portable variable-angle sand-proof tilt table in the storage state;

[0033] Fig.12 This is an example of a black and white marker.

[0034] The numbers in the figure are: 1. rotor; 2. camera; 3. ultrasonic anemometer; 31. ultrasonic anemometer body; 4. sand transport rate measuring instrument; 5. portable variable angle sand prevention tilt table; 51. tilt cover plate; 511. arc stick structure; 512. connecting protrusion; 52. tilt support plate; 53. tilt base; 531. semicircular groove; 532. protrusion; 533. rectangular through hole; 6. dust meter; 61. dust meter body; 62. connector II; 7. support I; 71. bottom plate I; 72. side ear; 73. square tube I; 74. connector I; 8. support II; 81. bottom plate II; 82. square tube II. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0036] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0038] Example 1

[0039] like Figure 1~Figure 2 As shown, the synchronous measurement device of the rotor wind and sand flow field mainly includes 6 groups of ultrasonic anemometers 3 (CSAT3B), 2 groups of sand transport rate measuring instruments 4 (SandFlow4, hereinafter referred to as SF4), 4 groups of dust meters 6 (Dusttrack8530), and 1 group of black and white markers, a total of four instruments for measuring wind speed, surface sand transport rate, air dust concentration and field visibility. In addition, the wind and sand flow field is caused by the rotor 1. A camera 2 is set directly below the rotor 1 for real-time video shooting, which is convenient for later acquisition of data at the same time, realizing synchronous measurement, and eliminating the influence of time factors. Among them, the pitch angle of the camera 2 can be adjusted, such as Figure 3 As shown in the figure, the straight line on the right represents the center line of the camera field of view at a given pitch angle, and the angle between the straight line and the ground is The left straight line is the symmetrical line of the camera's field of view centerline. The helicopter pilot's field of view angle when observing the ground (the angle between the line of sight and the ground plane) ) is generally between 10 and 45 degrees, in order to match the angle range of the tilt table, You can choose an angle that is an integer multiple of 5 between 5 and 50 degrees, which can satisfy both the actual field of view and the measurement requirements.

[0040] Among them, Figure 4 As shown, the ultrasonic anemometer 3 is connected to the support I 7 through a connector I 74. The support I 7 is composed of a rectangular bottom plate I 71 with side ears 72 and a square tube I 73 with a circular through hole. The square tube I 73 is vertically fixed in the center of the rectangular bottom plate I 71; Figure 5 As shown, the connecting member 1 74 comprises two parts: a vertical plate and a horizontal sleeve. The connecting member 1 74 is fixedly connected to the circular through hole on the square tube 1 73 through the through hole on the vertical plate of the connecting member 1 74. The installation sleeve of the ultrasonic anemometer body 31 is sleeved on the horizontal sleeve of the connecting member 1 74. Figure 6 As shown, the dust monitor 6 is connected to a support I 7 via a connecting piece II 62, as shown in FIG. Figure 7As shown, the connector II 62 includes two parts: a vertical plate and a horizontal plate connected vertically. The connector II 62 is fixedly connected to the circular through hole on the square tube I73 through the through hole on the vertical plate of the connector II 62, and the dust monitor body 61 is connected to the horizontal plate of the connector II 62 by bolts. The side ears 72 of the support I7 are mainly used to increase the anti-tilting ability of the support I7. The thickness of the bottom plate is 1cm, the height of the square tube I73 is 148.5cm, and the diameter of the circular through holes thereon is 6mm. The lowest through hole is 2.5cm higher than the upper surface of the bottom plate I71, and the spacing between adjacent circular through holes upward is 5cm. The support I7 mainly plays the role of fixing the position of the instrument to prevent the instrument from shaking or even falling in a strong wind and sand environment. The placement position of the support I7 on the laboratory floor determines the horizontal plane orientation of the measuring point. The whole consisting of the measuring instrument and the connector selects different installation positions on the support I7 to determine the height of the measuring point from the ground. Ignoring the volume of the instrument itself, theoretically, the support 1 7 can measure the relevant data of all spatial positions within the height range of 6 cm to 146 cm above the laboratory floor. Six groups of ultrasonic anemometers 3 are arranged at different polar angles and different polar diameters. Considering the volume of the instrument and the fixed support itself, the mutual influence between the instruments should be minimized when placing them. The six groups of ultrasonic anemometers 3 can be placed at polar angles of 90 degrees, 135 degrees, 225 degrees, 270 degrees, 315 degrees, and 45 degrees. In order to measure the wind speed at more polar diameters at one time, the ultrasonic anemometers 3 placed at each polar angle should choose different polar diameters within the range of [1R, 4.5R]. Along the counterclockwise direction (the rotation direction of the rotor 1), the polar diameter position of the instrument is gradually increased to minimize the interference of the instrument on the flow field. Specifically, it can be placed at the following positions: (90 degrees, 1.3R), (135 degrees, 1.9R), (225 degrees, 2.5R), (270 degrees, 3.1R), (315 degrees, 3.7R), (45 degrees, 4.3R). The arrangement position in the figure is mainly used to measure the ground jet velocity (i.e. the velocity along the polar radius outward on the ground). The probe faces the rotating shaft of the rotor 1, so that the influence of the volume of the ultrasonic anemometer 3 on the ground jet is minimized, thereby increasing the reliability of the ground jet wind speed data. The measurement point of the dust monitor 6 is arranged on the symmetrical line of the center line of the camera field of view ( Figure 3 The dust concentration at different spatial positions on the center line of the camera's field of view is indirectly obtained. The measured concentration is thus related to visibility.

[0041] like Figure 8As shown, both ends of the sediment transport rate measuring instrument 4 are fixed on a support II8 through a connecting piece II 62 respectively, and the support II8 is composed of a rectangular base plate II 81 and a square tube II 82 with a circular through hole, and the square tube II 82 is vertically fixed in the center of the rectangular base plate II 81; the connecting piece II 62 is fixedly connected with the circular through hole of the square tube II82 through the through hole on the vertical plate of the connecting piece II 62, and both ends of the sediment transport rate measuring instrument 4 are connected to the horizontal plate of the connecting piece II 62 by bolts. The centers of the measuring tubes of the two sets of sediment transport rate measuring instruments 4 are located at different polar diameters at the same polar angle. Two sediment transport rate measuring instruments 4 are placed at the polar angle of 0 degrees. Since the sand-raising position is often larger than the radius R of the rotor 1, and considering that placing the black and white markers at the polar angle position of the sediment transport rate measuring instrument 4 can maximize the space utilization, the distance between the center of the sediment transport rate measuring instrument 4 and the rotating shaft of the rotor 1 should be within the range of [1.5R, 4.5R]. In order to reduce the mutual influence between the two sediment transport rate measuring instruments 4, the distance between the two sediment transport rate measuring instruments 4 should be greater than 1R. Specifically, they can be placed at the following positions: (0 degrees, 2.5R), (0 degrees, 3.5R).

[0042] The black and white marker is fixed on a portable variable angle sand-proof tilting platform 5, such as Figures 9-11 As shown, the portable variable-angle sand-proof tilting platform 5 is composed of a tilting cover plate 51, a tilting base 53 and a tilting support plate 52. The tilting cover plate 51 and the tilting base 53 are detachably connected, and the tilting support plate 52 is detachably connected to the tilting cover plate 51. One end of the tilting cover plate 51 is configured as a circular arc stick-shaped structure 511. The left side of the tilting base 53 is provided with a semicircular groove 531 matching the circular arc stick-shaped structure 511 at the end of the tilting cover plate 51. The raised portion 532 on the rear side of the tilting base 53 is located at a corresponding position of the semicircular groove 531 and is provided with a cover mounting hole matching the circular arc stick-shaped structure 511. The tilting cover plate 51 is provided with a The connecting protrusion 512 connecting the tilt support plate 52 and the two rectangular through holes 533 on the tilt base 53 are convenient for storing the connecting protrusion 512 of the tilt cover plate 51, so that the tilt cover plate 51 fits on the tilt base 53 in the stored state; a groove is arranged below the tilt base 53 for placing the tilt support plate 52 in the stored state; the tilt base 53 is provided with 10 convex strips (a quarter arc slide groove), which are 85 degrees, 80 degrees... (every 5 degrees)... 40 degrees from left to right, and each convex strip has a support plate mounting hole on the rear side. Advantages of the portable variable angle sand-proof tilt table 5: (1) easy to store and carry; (2) simple structure with good sand-proof performance; (3) variable angle and no need to measure the angle manually.

[0043] like Fig.12The figure shows an example of a black and white marker. The tilt cover 51 with the black and white marker is adjusted to , move its position so that the center line of the camera's field of view passes through the center of the black and white marker, thus ensuring that the plane of the black and white marker is perpendicular to the center line of the camera's field of view, and by adjusting the focal length of camera 2, make the focal plane coincide with the plane of the black and white marker.

[0044] The above scheme will be described in detail below in conjunction with specific embodiments and experimental data regarding the measurement steps.

[0045] Example 2

[0046] This embodiment provides a specific sand flow field simulation and related parameter measurement and calculation process, the specific steps are:

[0047] (1) First, dry natural sand is spread on the ground. The thickness of the sand bed is 1.5 cm. The shape of the sand bed is a circle with a radius of 4 meters. The center of the circle is directly below the rotation axis of the rotor 1. The radius R of the rotor 1 (the length of a single rotor blade) is 0.5 m. The height H of the rotor 1 can be adjusted. In this embodiment, Let me give you an example.

[0048] (2) Place a camera bracket directly below the rotor 1. The camera bracket can adjust the installation height and angle of camera 2. Camera 2 is installed on the camera bracket. The height of the camera 2 from the rotor 1 is adjusted to 15 cm. The angle is adjusted to the observation angle required for this experiment. In order to ensure that the line of sight is perpendicular to the tilt cover 51 in the use state, in a single experiment (Angle between sight and ground) can be selected as an integer multiple of 5 in the range of 5 to 50 degrees. Let me give you an example.

[0049] (3) Determine the placement position of the center of the rotating shaft of the portable variable-angle sand-proof tilting platform 5. The tilting cover 51 is perpendicular to the line of sight, so the angle between it and the ground is , the distance between its center and the ground is , so the height difference between the installation position of camera 2 and the center of the tilt cover 51 is , calculate the distance between the center of the rotating shaft of the portable variable angle sand-proof tilt platform 5 and the rotating shaft of the rotor 1 Therefore, the center position of the rotating shaft of the portable variable angle sand-proof tilting platform 5 can be selected at ( ) at the polar coordinate position.

[0050] (4) Determine the center placement of SF4 (sediment transport rate measuring instrument 4). Generally speaking, in order to measure the surface sediment transport rate, SF4 is installed at the two lowest holes of support II 8. SF4 is the shortest of all devices and has the least obstruction to the line of sight, so SF4 should be placed in the same polar angle direction as the tilt table, that is, direction, since the sand-raising position is often larger than the radius of the rotor 1, in order to reduce the mutual influence between the two SF4, the distance between the two sand transport rate measuring instruments 4 should be greater than 1R. In this embodiment, the two SF4 are placed at the following positions: ( ), (0 ).

[0051] (5) Determine the placement position of the measurement port of the dust monitor 6. Since the concentration data measured by the dust monitor 6 will eventually be compared with the visibility data, the dust monitor 6 is placed on the symmetrical line of the camera 2 field of view. Since the heights of different radial positions of the field of view are different, the installation position of the dust monitor 6 on the bracket is also different. The measurement port of the dust monitor 6 is 60 cm higher than the installation position. The bracket installation holes are 1, 2... holes from bottom to top. The dust monitor 6 is installed on holes 1 to 2 of the bracket, and the measurement port height is 66 cm; installed on holes 3 to 4 of the bracket, the measurement port height is 76 cm; installed on holes 5 to 6 of the bracket, the measurement port height is 86 cm; installed on holes 7 to 8 of the bracket, the measurement port height is 96 cm; according to , it can be calculated that the placement positions of the four groups of dust monitors 6 with heights of 66cm, 76cm, 86cm, and 96cm are ( )、 , , .

[0052] (6) Determine the placement position of the two probe centers of the ultrasonic anemometer 3. This embodiment takes the measurement of surface wind speed as an example. In order to measure the surface wind speed, the ultrasonic anemometer 3 is installed at the holes 1 to 2 of the bracket, so that its measurement height is 6 cm; the placement position is similar to an equiangular spiral with counterclockwise as the positive direction. The purpose of this is to reduce the interference of the previous ultrasonic anemometer 3 on the next ultrasonic anemometer 3 when the rotor 1 rotates counterclockwise. However, considering the actual space limitations, and Other instruments have been placed on the polar angle line, so the ultrasonic anemometer 3 cannot be placed. The specific placement position after the equiangular spiral is modified is as follows: ( )、( )、( )、( )、( )、( ).

[0053] (7) Use a protractor and a steel ruler to determine the above polar coordinate positions, and leave corresponding position marks on the sand surface.

[0054] (8) SF4 is fixed to the 1-2 holes of the square tube II82 in the support II 8 through the connector II 62. Align the center of the SF4 measuring tube to the predetermined coordinates. The polar lines are vertical.

[0055] (9) The four dust monitors 6 are fixed to the 1-2 holes, 3-4 holes, 5-6 holes, and 7-8 holes of the four supports I 7 through the connector II 62. A plumb bob is hung directly below the measuring port and aligned with the predetermined position. The non-porous surface of the square tube I 73 on the support I 7 is perpendicular to the Polar line.

[0056] (10) The ultrasonic anemometer 3 is connected to the holes 1-2 of the square tube I 73 in the support I 7 through the connector I 74, the midpoint of the line connecting the two measuring claws is aligned with the predetermined position, and the instrument is facing the rotating shaft of the rotor 1.

[0057] (11) Before rotating rotor 1, turn on all instruments to put them in working condition and calibrate the instrument time.

[0058] (12) The rotor 1 is controlled to rotate. During the rotation process, SF4 monitors the sand transport rate near the measuring position in real time, the dust meter 6 monitors the dust concentration near the measuring port in real time, the ultrasonic anemometer 3 monitors the three-dimensional wind speed near the measuring point in real time, and the camera 2 focuses on the center of the black and white marker on the tilt cover 51 to shoot a video in real time.

[0059] (13) After rotor 1 stops, the data of each instrument and camera 2 are exported and the corresponding time of the data is unified. This operation is mainly achieved by taking the intersection of the Beijing time of each instrument.

[0060] (14) Calculation of field of view concentration: ,in Represents the concentration data measured by the i-th dust monitor 6.

[0061] (15) Visibility calculation: Identify the four corner points in the image and mark the intersection of the diagonal lines connecting the four corner points as point O. The ratio of the black-and-white image of the marker to the real object is k. Then, the circle with O as the center of the image and r (r is smaller than the circumference of the marker) as the radius in the real object is located at the The spatial frequencies of the quadrant arcs are , if the spatial frequency is equal to f, then we can solve , No. The coordinates of the arc in the quadrant satisfy , the pixels of the arc in each quadrant are classified into black and white categories, and the black area expression is , white area expression , No. The pixel coordinates of the arc with spatial frequency equal to f in the quadrant can be obtained by the following steps: (1) establish a pixel grid; (2) substitute the coordinates of the adjacent corner points of the grid into the arc equation (3) If they are of different signs, then the two pixels bounded by the line connecting the two corner points are both pixels through which the arc passes; (4) If the result of substituting one of the corner points is 0, then a pixel around the point is randomly selected as a pixel through which the arc passes; (5) Count the positions and numbers of all coordinates, and record the same coordinates repeatedly. The average gray value of the black pixels in the quadrant arc is, ( For the The number of black pixels in the quadrant arc);

[0062] ,

[0063] No. The average gray value of white pixels in the quadrant arc is, ( For the The number of white pixels in the quadrant arc),

[0064] ;

[0065] The average contrast ratio is .

[0066] in express The gray value of the pixel at It represents the average gray value of the pixel. In the eight-bit grayscale, pure black is 0 and pure white is 255. The real object is a pure black and white photo, and the theoretical contrast is 255, so the normalized contrast is D= Normalized contrast can be used as a measure of visibility. With the x-axis as spatial frequency, the y-axis as time, and the z-axis as visibility (represented by D), the visibility changes of physical details of different spatial frequencies over time can be obtained.

[0067] (16) Establishment of the relationship between visibility and concentration: based on spatial frequency For example, by fitting , we can get the functional relationship between visibility and concentration .

[0068] (17) The ultrasonic anemometer 3 obtains the real-time three-dimensional wind speed on the surface at a given radial position on the surface, and obtains the real-time three-dimensional wind speed on the surface at all radial positions by interpolation.

[0069] (18) SF4 obtains the real-time sediment transport rate at a given radial position on the surface.

[0070] (19) Since the surface wind speed measurement location is different from the sediment transport rate measurement location, the real-time wind speed obtained by interpolation is used at the sediment transport rate measurement location. The correlation between the sediment transport rate fluctuation and the wind speed fluctuation can be analyzed by spectral analysis method.

[0071] (20) The data of dust monitor 6 at the sediment transport rate measurement point can be interpolated and combined with the sediment transport rate measurement data to carry out the correlation analysis between concentration and sediment transport rate.

[0072] (21) In summary, the multi-factor synchronous measurement technology can realize the quantitative analysis of visibility and concentration, as well as the correlation analysis between concentration and sediment transport rate, and between sediment transport rate and wind speed.

[0073] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A synchronous measurement device for rotor wind and sand flow field, comprising an ultrasonic anemometer, a sand transport rate measuring instrument, a dust meter, and a black and white marker, characterized in that: It also includes a camera arranged directly below the rotor; a polar coordinate system is constructed with the ground directly below the rotor as the measurement center and the measurement center as the pole, and the length of the single rotor is R; the ultrasonic anemometer is provided with 6 groups, and the 6 groups of ultrasonic anemometers are respectively arranged at different polar diameters with polar angles of 45°, 90°, 135°, 225°, 270°, and 315°, and the polar diameter range of the ultrasonic anemometer is 1R~4.5R; the sediment transport rate measuring instrument is provided with two groups, and the two groups of sediment transport rate measuring instruments are located at different polar diameters of the same polar angle, and the polar diameter range of the sediment transport rate measuring instrument is 1.5R~4.5R, and the two The distance of the sediment transport rate measuring instrument is greater than 1R; the angle between the center line of the field of view of the camera and the ground is θ, and θ is an integer multiple of 5 between 5 and 50°; the tilt angle between the plane where the black and white marker is located and the ground is 90°-θ, and the black and white marker is within the center line of the field of view of the camera, and the center line of the field of view of the camera is perpendicular to the plane where the black and white marker is located; the dust meter is provided with 4 groups, and the measuring points of the 4 groups of dust meters are set on the symmetric line of the center line of the field of view of the camera; wherein the black and white marker is used to calculate visibility, and the relevant process of using the black and white marker to calculate visibility is: The camera takes a black and white image of the marker, identifies the four corner points in the photographed black and white image, marks the intersection of the diagonal lines of the four corner points as point O, and the ratio of the photographed black and white image to the real object is k. The image takes O as the coordinate center, and the circumference of the real object with a radius of r, where r is smaller than the circumference of the black and white marker, and the spatial frequencies of the arc in the λth quadrant are If the spatial frequency is equal to f, then we solve The coordinates of the arc in the λth quadrant satisfy The pixels of the arc in each quadrant are classified into black and white categories. The black area expression White area expression The pixel coordinates of the arc with spatial frequency equal to f in the λth quadrant can be obtained by the following steps: (1) establish a pixel grid; (2) substitute the coordinates of the adjacent corner points of the grid into the arc equation If they are of different signs, then the two pixels bounded by the line connecting the two corner points are both pixels through which the arc passes; (4) If the result of substituting one of the corner points is 0, then a pixel around the point is randomly selected as a pixel through which the arc passes; (5) Count all coordinate positions and numbers, and record the same coordinates repeatedly; then the average grayscale value of the black pixels in the arc of the λth quadrant is: in Among them, N b,λ is the number of black pixels in the arc of the λth quadrant, and I(x,y) represents the grayscale value of the pixel at (x,y); The average gray value of white pixels in the λth quadrant arc is: in Among them, N w,λ is the number of white pixels in the arc of the λth quadrant, and I(x,y) represents the grayscale value of the pixel at (x,y); The average contrast ratio is In eight-bit grayscale, pure black is 0 and pure white is 255. The actual black and white sign is a pure black and white photo, and the theoretical contrast is 255. Therefore, the normalized contrast is D = Δ / 255. Normalized contrast is used as a measure of visibility, with the x-axis as spatial frequency, the y-axis as time, and the z-axis as visibility. The normalized contrast D is used to characterize visibility, and the visibility changes of the actual details of different spatial frequencies over time are obtained.

2. The synchronous measurement device for rotor wind-sand flow field according to claim 1, characterized in that: The polar diameters of the six groups of ultrasonic anemometers increase in the order of polar angles of 90°, 135°, 225°, 270°, 315°, and 45°.

3. The synchronous measurement device for rotor wind-sand flow field according to claim 1, characterized in that: The polar angle and polar diameter parameters of the two groups of sediment transport rate measuring instruments are (0 degrees, 2.5R) and (0 degrees, 3.5R) respectively.

4. The synchronous measurement device for the rotor wind-sand flow field according to claim 1, characterized in that: The ultrasonic anemometer is connected to a support I through a connecting piece I, and the support I is composed of a rectangular base plate with side ears and a square tube with circular through holes, and the square tube is vertically fixed in the center of the rectangular base plate; the connecting piece I includes two parts, a vertical plate and a horizontal sleeve, and the connecting piece I is fixedly connected to the square tube of the support I through the through hole on the vertical plate of the connecting piece I, and the installation sleeve of the ultrasonic anemometer is sleeved outside the horizontal sleeve.

5. The synchronous measurement device for rotor wind-sand flow field according to claim 4, characterized in that: The dust monitor is connected to a support I through a connecting piece II, and the connecting piece II comprises two parts, a vertical plate and a horizontal plate, which are vertically connected. The connecting piece II is fixedly connected to the square tube of the support I through a through hole on the vertical plate of the connecting piece II, and the dust monitor is connected to the horizontal plate of the connecting piece II by bolts.

6. The synchronous measurement device for rotor wind-sand flow field according to claim 5, characterized in that: The two ends of the sediment transport rate measuring instrument are respectively fixed on a support II through a connecting piece II, and the support II is composed of a rectangular base plate and a square tube with a circular through hole, and the square tube is vertically fixed in the center of the rectangular base plate; the connecting piece II is fixedly connected to the square tube of the support II through the through hole on the vertical plate of the connecting piece II, and the two ends of the sediment transport rate measuring instrument are connected to the horizontal plate of the connecting piece II by bolts.

7. The synchronous measurement device for rotor wind-sand flow field according to claim 1, characterized in that: The black and white marker is fixed on a portable variable-angle sand-proof tilt platform, and the portable variable-angle sand-proof tilt platform consists of a tilt cover plate, a tilt base and a tilt support plate.

8. A synchronous measurement method for rotor wind-sand flow field using the synchronous measurement device according to any one of claims 1 to 7, characterized in that: The steps include: (1) Before the rotor rotates, turn on all instruments to ensure that they are in working condition and calibrate the instrument time; (2) Control the rotation of the rotor. During the rotation process, two sand transport rate measuring instruments monitor the sand transport rate near the measurement position in real time, the dust meter monitors the dust concentration near the measurement port in real time, and the ultrasonic anemometer monitors the three-dimensional wind speed near the measurement point in real time. The camera focuses on the center of the tilt table cover and shoots real-time video; (3) After the rotor stops, the data of each instrument and camera are exported and the corresponding time of the data is unified. Synchronous measurement is achieved by taking the intersection of the Beijing time of each instrument, calculating the field of view concentration and visibility, and realizing quantitative analysis of visibility and concentration, as well as correlation analysis between concentration and sediment transport rate, and between sediment transport rate and wind speed.

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