A high-speed wind erosion wind tunnel and a full-automatic wind erosion experiment system

Abstract

The application discloses a high-speed wind erosion wind tunnel and a full-automatic wind erosion experiment system. The high-speed wind erosion wind tunnel comprises a wind tunnel main body and a power device; the wind tunnel main body comprises a power section, a diffusion section, a rectification section, a contraction section and an experiment section which are sequentially communicated along an internal gas flow direction; the power device is arranged in the power section and is used for generating flowing gas; the power device comprises a turbocharged fan, an air outlet mechanism and an airfoil structure; the air outlet mechanism is communicated with the turbocharged fan and the power section, and makes the compressed gas provided by the turbocharged fan flow through the surface of the airfoil structure in a direction of being deviated or oriented to the internal gas flow direction and then enter the power section in a surrounding manner; the wind tunnel main body comprises a direct-current blowing type or a circulating blowing type structure. The high-speed wind erosion wind tunnel provided by the application has a natural and stable flow field, avoids the abrasion of sand on the blade and the shaft structure thereof, has a long service life, is high in safety, has stronger airflow, and the wind pressure, the air volume and the wind speed are obviously larger than those of the blade wind tunnel in the prior art.

Description

Technical Field

[0001] This invention relates to the field of wind and sand experimental equipment technology, and in particular to a high-speed wind erosion wind tunnel and a fully automatic wind erosion experimental system. Background Technology

[0002] Wind tunnels are the primary experimental equipment for studying wind erosion processes and aeolian landforms. They enable the study of the influence of various dynamic and environmental factors on wind erosion and micro-landform development under controlled conditions. General aviation, industrial, and high-speed transportation wind tunnels are closed-loop systems. Although they have high wind speeds, they cannot directly introduce media such as sand particles, as this would cause severe damage to components such as motors, rotor shafts, and blades. Therefore, they cannot be used for experimental simulations of wind erosion processes.

[0003] Wind tunnels for aeolian environments or wind erosion wind tunnels are widely used to simulate the initiation, transport, and deposition processes of wind erosion of various sediments. To avoid the impact of aeolian particles on components such as motors, rotor shafts, and blades, these wind tunnels are all open-circuit direct-flow blowing structures, generally using axial-flow blowing or centrifugal booster fans, resulting in relatively low wind speeds. Existing wind erosion wind tunnels typically have a maximum experimental wind speed of 40 m / s, while actual operating wind speeds are generally below 30 m / s. Therefore, they cannot meet the requirements for wind erosion experiments on aeolian gravel flows in high-wind environments (wind speeds of 70 m / s). For example, in the Baili Wind Zone of Xinjiang Uygur Autonomous Region, through which the Lanzhou-Xinjiang High-Speed ​​Railway passes, the instantaneous maximum wind speed can reach 68 m / s, which is the highest instantaneous wind speed record recorded in inland my country. Furthermore, many transportation lines in Northwest my country have maximum wind speeds exceeding 40 m / s along their routes, such as the Golmud-Korla Railway, the Harold-London Railway, and the Jiuquan-Erlian Railway. These railway lines bear important functions in transportation for aerospace, national defense, and resources, but high-intensity wind-blown sandstorms and sand burial hazards along the lines pose a significant threat to their operational safety. Due to harsh natural conditions, it is difficult to conduct systematic and precise field observation experiments, resulting in a lack of understanding of the transport process and disaster-causing mechanism of wind-blown sandstorms under high wind conditions. Currently, directly applying the same or similar sandstorm control measures to high-wind-speed areas has had minimal effect.

[0004] Wind tunnel simulation experiments of wind erosion processes in environments with strong winds and strong sand transport (such as Gobi Desert, sandy coasts, and islands) are an ideal way to explore the movement law of wind-blown sand and gravel flows in the region. However, existing wind erosion wind tunnels cannot carry out simulation experiments of sand-carrying winds under high wind speeds (70 m / s), which limits the study of wind erosion processes under such high wind speeds.

[0005] Besides the fact that existing wind tunnels lack the ability to simulate wind erosion processes under high wind speeds, the experimental measurement systems used in conjunction with wind tunnels also have shortcomings, mainly in the following three aspects:

[0006] First, existing gradient-type sediment collectors for acquiring sediment transport profiles lack automatic data acquisition capabilities. They rely solely on manual weighing after each experiment to obtain cumulative data on sediment transport at different heights over a specific time period. Therefore, they cannot accurately capture the time-varying characteristics of aeolian sand transport processes, significantly limiting the in-depth development of wind erosion research. For example, on uneven gravel-mixed beds, finer particles are eroded first, resulting in a larger initial sediment transport volume, which gradually decreases over time. Existing gradient-type sediment collectors can only obtain the cumulative sediment transport value over a period of time, making it difficult to capture real-time changes in sediment transport during bed coarsening. Furthermore, on wet sand beds, sediment transport continuously increases with evaporation, while experimental results only provide a cumulative value over a period, which cannot be fitted to the changing bed humidity. Therefore, the limitations of existing sediment collectors restrict further research into aeolian sand transport processes.

[0007] The more advanced "wind tunnel sand collector" is equipped with an electronic scale and has automatic data acquisition capabilities. However, its sand collection box has a single-row layout, which limits its diameter to only 2 cm and length to 20 cm, resulting in a small volume and short standby time – a common problem with traditional sand collectors. Another limitation is that the single-row layout increases the height of the sand collector, making the inclined connection between the upper sand collection tube and the sand collection tank very long. This hinders the smooth and timely entry of sand particles into the sand collection tank, leading to data delays. Therefore, it is essential to develop a gradient sand collector with automatic and accurate data acquisition, larger capacity, and longer standby time.

[0008] Secondly, accurately determining the starting wind speed of wind-eroded sand particles is of great significance for the study of wind erosion physics. However, due to the instantaneous, high-speed, and minute kinematic characteristics of sand particles at the moment of initiation, the starting wind speed is an experimental constant that is difficult to measure accurately, and researchers have used various methods. Currently, there are five main methods for measuring the starting wind speed: visual identification, tape method, sheet light source observation method, wind erosion sensor, and fork-type photoelectric sensor. However, each of these methods has its own shortcomings and cannot objectively and accurately measure the starting wind speed of wind-eroded sand particles.

[0009] Furthermore, the length, width, and depth of the experimental sand trays used to lay sediments in wind tunnels often need to be adjusted depending on the type, quantity, particle size, erosion time, and surface humidity of the sediment samples. The size and length of the sand trays required for wind tunnel simulation experiments of different aeolian processes (initiation, transport, or abrasion processes) also vary. For example, simulating the initiation process only requires a sand tray at least 60 cm long, while simulating dry sand transport processes to obtain saturated aeolian flow requires a sand tray at least 4 meters long. For wet sand or gravel-mixed bed surfaces, this length needs to be increased to 6-10 meters. Therefore, before each experiment, sand trays often need to be remade or modified according to the specific process or object being simulated. This is often labor-intensive and time-consuming, resulting in waste of the wind tunnel floor and reduced experimental efficiency.

[0010] In summary, developing a high-speed wind erosion wind tunnel and its supporting fully automated experimental system, with a natural and stable flow field and a wind speed of up to 70 m / s in the experimental section, to meet the needs of wind erosion research under high wind conditions and improve the precision and automation of wind erosion parameter data acquisition, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0011] To address the shortcomings of existing technologies, the present invention aims to provide a high-speed wind erosion wind tunnel and a fully automated wind erosion experimental system.

[0012] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0013] In a first aspect, the present invention provides a high-speed wind erosion wind tunnel, comprising a wind tunnel body and a power unit; the wind tunnel body comprises a power section, a diffusion section, a rectification section, a contraction section and an experimental section connected sequentially along the internal gas flow direction; the power unit is disposed in the power section and is used to generate flowing gas; the power unit comprises a turbocharger, an exhaust mechanism and an airfoil structure; the exhaust mechanism connects the turbocharger and the power section, and causes the compressed gas provided by the turbocharger to flow through the surface of the airfoil structure in a direction deflected or toward the internal gas flow direction and then enter the power section.

[0014] Secondly, the present invention also provides a fully automated wind erosion experimental system, characterized in that it includes the above-mentioned high-speed wind erosion wind tunnel and testing components; the testing components include: a fully automated sand transport profile testing unit, which is used at least to measure the time series data of the sand transport profile within the experimental section;

[0015] In some preferred embodiments, a fully automated starting wind speed testing unit is also included, which is used at least to determine the starting wind speed of the sediments in the experimental section;

[0016] In some preferred embodiments, a telescopic sand table testing unit with adjustable length and width is also included.

[0017] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include:

[0018] 1. The high-speed wind tunnel provided by this invention has no blades or their shaft structure inside the tunnel, which avoids the violent wind impact, eddies and rotating wind generated by blades cutting the air to drive the airflow. The flow field is natural and stable, and it avoids the wear of wind and sand on the blades and their shaft structure. It has a long service life and high safety.

[0019] 2. The bladeless fan of the high-speed wind erosion wind tunnel provided by this invention utilizes a turbocharger and air multiplication effect to generate stronger airflow. The wind pressure, air volume and wind speed are significantly greater than those of the bladed wind tunnels in the prior art. The wind speed in the experimental section can reach 70m / s, which meets the needs of wind erosion research in high wind environments.

[0020] 3. The fully automatic wind erosion experimental system provided by this invention can combine high wind speed, high flow field quality with a fully automatic sand transport profile testing unit, which is beneficial for sand grain transport at high altitudes and the sand transport will be more uniform in height distribution. It can accurately capture the sand transport pattern that is difficult to observe in wind erosion tunnels in the existing technology. It can also combine high wind speed, high flow field quality with a fully automatic starting wind speed testing unit, which can realize the observation of large-diameter gravel jump start that is impossible in wind erosion tunnels in the existing technology.

[0021] The above description is only an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of this application are described below with reference to detailed drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the main structure of a DC blowing wind tunnel provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of a circulating air blowing wind tunnel body provided in an embodiment of the present invention;

[0024] Figure 3 This is a front structural diagram of a bladeless fan provided in an embodiment of the present invention;

[0025] Figure 4 This is a three-dimensional structural schematic diagram of a bladeless fan provided in an embodiment of the present invention;

[0026] Figure 5 This is a partial cross-sectional structural diagram of a bladeless fan provided in an embodiment of the present invention;

[0027] Figure 6This is a schematic diagram of the structure of a fully automatic sand transport profile testing unit provided in an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the sand accumulation bucket arrangement of a fully automatic sand conveying profile testing unit provided in an embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the electronic scale arrangement of a fully automatic sand conveying profile testing unit provided in an embodiment of the present invention;

[0030] Figure 9 This is a front structural diagram of a fully automatic starting wind speed testing unit provided in an embodiment of the present invention;

[0031] Figure 10 This is a top view of the structure of a telescopic sand table testing unit when forming a large sand table, as provided in an embodiment of the present invention.

[0032] Figure 11 This is a top view of the structure of a telescopic sand table testing unit when forming a smaller sand table, as provided in an embodiment of the present invention.

[0033] Figure 12 This is a schematic diagram of a partial connection structure of a telescopic sand table testing unit provided in an embodiment of the present invention;

[0034] Figure 13 This is a partial structural diagram of the sand leakage port of a telescopic sand table testing unit provided in an embodiment of the present invention;

[0035] Explanation of reference numerals in the attached figures:

[0036] 10. Main body of the wind tunnel;

[0037] 101. Power Section; 102. Diffusion Section; 103. Rectification Section; 104. Contraction Section; 105. Experimental Section; 106. Connecting Section; 107. Turning Connecting Section; 108. Low Temperature Section;

[0038] 20. Power unit;

[0039] 201. Bladeless fan; 202. Turbine booster fan; 203. Air outlet mechanism; 204. Airfoil structure; 205. Annular air duct; 206. Annular air outlet; 207. Variable frequency controller; 208. Heating device; 209. Gas generator; 210. Flow field structure;

[0040] 30. Fully automated testing unit for sand conveying profiles;

[0041] 301. Sand collection pipe; 302. Extension section; 303. Sand collection bucket; 304. Electronic scale; 305. Data acquisition instrument; 306. Sand collection box; 307. Sand collection cover; 308. Inclined part;

[0042] 40. Fully automatic start-up wind speed test unit;

[0043] 401. Sand table; 402. Sand laying section; 403. Narrowing section; 404. Shooting channel; 405. Sand collection tank; 406. Identification area; 407. Miniature high-speed camera; 408. Sand scraper; 409. Upwind extension section; 410. Lifting platform; 411. Magnifying glass; 412. Camera bracket; 413. Gradient Pitot tube; 414. Data acquisition device; 415. Computer;

[0044] 50. Telescopic sand table testing unit;

[0045] 501. Base plate; 502. Horizontal embedded track; 503. Longitudinal embedded track; 504. Horizontal slide bar; 505. Longitudinal slide bar; 506. Slide bar base; 507. Sand leakage port; 508. Leak-stopping disc; 509. Fixed shaft; 510. Sand collector mounting port. Detailed Implementation

[0046] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0047] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0048] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component or method step from another that has the same name, and do not necessarily require or imply any such actual relationship or order between these components or method steps.

[0049] See Figures 1-5 This invention provides a high-speed wind erosion wind tunnel, including a wind tunnel body 10 and a power unit 20;

[0050] The wind tunnel body 10 includes a power section 101, a diffusion section 102, a rectification section 103, a contraction section 104, and an experimental section 105 connected sequentially along the internal gas flow direction. The power unit 20 is located in the power section 101 and is used to generate flowing gas.

[0051] The power unit 20 includes a turbocharger 202, an exhaust mechanism 203, and an airfoil structure 204. The exhaust mechanism 203 connects the turbocharger 202 and the power section 101, and causes the compressed gas provided by the turbocharger 202 to flow through the surface of the airfoil structure 204 in a direction deviating from or toward the internal gas flow direction before circulating into the power section 101.

[0052] Among them, the airfoil structure 204 refers to a structure with a cross-sectional shape of an airfoil. When the airflow flows through the airfoil structure 204, it is converged and accelerated. Based on Bernoulli's law, when the velocity of an inviscid fluid increases, the total pressure or potential energy of the fluid will decrease, forming an airflow with a wind speed and volume much greater than the surrounding airflow. The air pressure difference generated by this high-speed airflow introduces the air behind and around the air outlet mechanism 203, forming a larger airflow. The airfoil structure 204 can be a separately set air surface structure, for example, a ring airfoil structure 204 fixed inside the power section 101, or as described below, such that at least the annular air passage 205 has the cross-sectional shape of an airfoil. The compressed gas can be implemented by entering the power section 101 in a ring-shaped air outlet 206 as described below, or by multiple independent air outlets distributed in a ring along the inner wall of the power section 101.

[0053] See Figures 2-5 In some embodiments, the air outlet mechanism 203 includes an annular air passage 205 communicating with the turbocharger fan 202 and an annular air outlet 206 disposed on the inner surface of the annular air passage 205.

[0054] The annular air passage 205 has an airfoil cross-sectional shape on at least a portion of the inner surface of the side facing the annular air outlet 206 to form the airfoil structure 204.

[0055] In some embodiments, the rated power of the turbocharger fan 202 is 200-500kW, and the power unit 20 further includes a frequency converter 207 electrically connected to the turbocharger fan 202, the frequency converter 207 having a frequency range of 0-50Hz.

[0056] In some embodiments, the power unit 20 includes a heating device 208 for regulating the temperature of the compressed air entering the power section 101;

[0057] In some embodiments, the heating device 208 includes an annular ceramic heating wire disposed in the annular air passage 205;

[0058] And / or, the power unit 20 includes a gas generator 209 for adjusting the composition of the compressed air;

[0059] In some embodiments, the gas generator 209 includes one or more combinations of a carbon dioxide generator, a nitrogen generator, an oxygen generator, and a humidified air generator.

[0060] In a typical implementation, the power unit 20 includes three parts: a bladeless fan 201, a frequency converter 207, and a gas generator 209, all located in the power section 101. These components are used to regulate the wind speed, airflow temperature and humidity, and gas composition within the wind tunnel body 10. The bladeless fan 201 comprises an annular air duct 205 and a base system. The base system includes a base cavity with an air inlet, a turbocharger fan 202 installed inside the cavity, and a base for the turbocharger fan 202. An annular heating ceramic wire is installed inside the annular air duct 205. The gas generator 209 comprises four parts: a carbon dioxide generator, a nitrogen generator, an oxygen generator, and a humidified air generator.

[0061] The bladeless fan 201 utilizes the principle of an air multiplier. A turbocharger fan 202 (with a rated motor power of 200-500 kW) draws in and pressurizes air from around the base, directing it to the annular air duct 205 above. The air is then ejected along the annular outlet 206, forming an airflow. This airflow is converged and accelerated by the air guide duct of the airfoil structure 204. Based on Bernoulli's principle, as the velocity of an inviscid fluid increases, the total pressure or potential energy of the fluid decreases, creating an airflow with a speed and volume far exceeding the surrounding air. This high-speed airflow generates a pressure difference that draws in air from behind and around the outlet mechanism 203, accelerating and amplifying it to form a stable and powerful airflow that is then blown out. Figure 5 The flow field structure 210 is shown.

[0062] The turbocharger fan 202 is connected to the frequency converter 207 (frequency range 0-50Hz) outside the base, so that the outlet wind speed of the annular air duct 205 can be continuously adjusted in the range of 0-50m / s, and the wind speed of the corresponding experimental section 105 can be continuously adjusted in the range of 0-70m / s.

[0063] See also Figure 1 and Figure 2 In some implementations, the wind tunnel body 10 includes a direct-flow air-blowing structure or a circulating air-blowing structure;

[0064] The DC blowing structure also includes a connecting section 106 disposed between the power section 101 and the diffuser section 102. The power section 101, the connecting section 106, the diffuser section 102, the rectifier section 103, the contraction section 104 and the experimental section 105 are connected sequentially in a straight line.

[0065] In a typical implementation case, the connecting section 106 is 1m long, 1.7m wide, and 1.2m high; the rectifying section 103 is 2.2m long, 2.4m wide, and 1.2m high; the diffuser section 102 is 1.8m long, with its inlet cross-section matching that of the connecting section 106 and its outlet cross-section matching that of the rectifying section 103; the contraction section 104 is 2.0m long, with its inlet cross-section matching that of the rectifying section 103 and its outlet width 1.0m and height 1.2m; the experimental section 105 is 25.0m long, 1.0m wide, and 1.2m high, and is divided into 10 equal segments, each 2.5m long.

[0066] Furthermore, the diffuser section 102 is provided with horizontal guide vanes and vertical guide vanes respectively;

[0067] Furthermore, the side windows and top window of the experimental section 105 are made of more than one layer of transparent tempered glass;

[0068] Furthermore, the rectifier section 103 is equipped with a honeycomb structure and a damping mesh;

[0069] Furthermore, the radial cross-section of each section in the wind tunnel body 10 is rectangular;

[0070] Furthermore, each structural section of the wind tunnel body 10 is connected to each other by flanges that are bent as a whole and have grooves, and rubber gaskets are sandwiched between the flanges.

[0071] Furthermore, all structural sections of the wind tunnel body 10 are made of stainless steel, and the wall thickness of each structural section is 3mm~5mm.

[0072] The circulating air blowing structure also includes a sand accumulation section located after the experimental section 105. The power section 101, diffusion section 102, rectification section 103, contraction section 104, experimental section 105 and sand accumulation section are connected end to end in a rectangle, and a turning connection section 107 is provided at the junction of any two sides of the rectangle.

[0073] In a typical implementation, the wind tunnel body 10 includes a power section 101, a first diffuser section 102, a rectifying section 103, a first contraction section 104, an experimental section 105, a second diffuser section 102, a first turning connection section 107, a first low-temperature section 108, a second turning connection section 107, a third diffuser section 102, a sand accumulation section (i.e., a bottom sand accumulation chamber), a second contraction section 104, a third turning connection section 107, and a second low-temperature section 108, wherein the second low-temperature section 108 is connected to the power section 101 via the fourth turning connection section 107.

[0074] In some embodiments, the lengths of the power section 101, the first diffusion section 102, the first contraction section 104, the experimental section 105, the second diffusion section 102, the first low-temperature section 108, the third diffusion section 102, the second contraction section 104, and the second low-temperature section 108 are respectively 1 / 10, 1 / 10, 1 / 5, 6 / 25, 3 / 50, 1 / 5, 4 / 25, 4 / 25, and 1 / 5 of the total length of the wind tunnel body 10.

[0075] See Figures 6-13 The present invention also provides a fully automated wind erosion experimental system, including the above-mentioned high-speed wind erosion wind tunnel and testing components;

[0076] The test components include:

[0077] The fully automated sand transport profile testing unit 30 is used at least to measure the time series data of the sand transport profile within the experimental section 105.

[0078] In some embodiments, the test components include: a fully automatic start-up wind speed test unit 40, for at least determining the start-up wind speed of sediments within the test section 105;

[0079] In some implementations, the test component includes a telescopic sand table test unit 50.

[0080] See also Figures 6-8 In some implementations, the fully automatic sand transport profile testing unit 30 includes multiple sand collection components, which include a sand collection pipe 301, an extension section 302, a sand collection bucket 303, an electronic scale 304, and a data acquisition instrument 305.

[0081] The first end of the sand collection pipe 301 extends horizontally and has an opening. The extension section 302 is connected to the second end of the sand collection pipe 301 and extends toward the sand collection bucket 303 so that the sand collected by the sand collection pipe 301 can fall into the sand collection bucket 303.

[0082] The openings of the multiple sand-collecting pipes 301 are distributed at different heights;

[0083] The electronic scale 304 is located below the sand collection bucket 303 and is used to weigh the mass of sand and dust in the sand collection bucket 303. The data acquisition instrument 305 is electrically connected to the electronic scale 304 and is used at least to record the weighing value of the electronic scale 304 in real time.

[0084] In some embodiments, the sand collection assembly further includes a sand collection box 306 and a sand collection cover 307, wherein the sand collection cover 307 is fastened to the opening of the sand collection box 306 to prevent sand and dust from entering the sand collection box 306 without passing through the sand collection pipe 301;

[0085] The sand collection pipe 301 passes through the sand collection cover 307 and is arranged in a straight line. The extension section 302 includes an inclined portion 308, so that the sand collection bucket 303 is arranged alternately left and right along the plane formed by the sand collection pipe 301, and the lengths of the inclined portions 308 of the multiple extension sections 302 are all equal.

[0086] In some implementations, the fully automated wind erosion experimental system further includes a wind erosion sensor and / or a wind speed profile sensor, and the data acquisition instrument 305 has an acquisition frequency of 1-100Hz, which is consistent with the acquisition frequency of the wind erosion sensor and / or the wind speed profile sensor.

[0087] In some typical implementation cases, the sand collection pipe 301, extension section 302, and sand collection cover 307 are welded together as an integral structure. The sand collection pipe 301 and extension section 302 are made of stainless steel square tubing, and the sand collection cover 307 is made of stainless steel plate. Each extension section 302 extends outwards to both sides, with its bottom opening extending into the inner edge of the corresponding sand collection bucket 303. Each sand collection pipe 301 and extension section 302 corresponds to a fixed-number sand collection bucket 303. Odd-numbered sand collection buckets 303 are arranged on the inner side of the sand collection box, and even-numbered sand collection buckets 303 are arranged on the outer side of the sand collection box. Each sand collection bucket 303 has a corresponding numbered electronic scale 304 at its bottom. The bottom of the sand collection bucket 303 is attached and fixed to its corresponding electronic scale 304. All electronic scales are connected to a data acquisition instrument 414 on the outside of the sand collection bucket 303 to collect time-series data of sand transport rates at different heights, i.e., time-series data of sand transport profiles.

[0088] The height of the sand collection pipe 301 at the top of the sand collection cover 307 is 40-60cm, and the height of the sand collection box at the bottom of the sand collection cover 307 is 40-50cm. The total height of this fully automatic sand conveying profiler is 80-110cm. The width of the opening of the sand collection pipe 301 is 2cm, and the height of the opening is 2cm, i.e., there is a height gradient every 2cm. The bottom of the extension section 302 of each sand collection opening is connected to a corresponding sand collection bucket 303 in the sand collection box, for a total of 20-30 sand collection buckets 303. Each sand collection bucket 303 is placed on a corresponding high-precision miniature electronic scale 304 and is glued and fixed to the scale 304. A total of 20-30 high-precision miniature electronic scales 304 are used to weigh each sand collection bucket 303. The high-precision miniature electronic scale 304 is a cylindrical structure of stainless steel, with a diameter of 4-5cm and a height of 2-3cm. The sand collection bucket 303 is a stainless steel cylindrical bucket with an open top, a diameter of 6-7cm, and a height of 20-30cm. Synchronous data acquisition is performed using a CR1000X data acquisition instrument 414 equipped with an expansion card slot, with an acquisition frequency of 1-100Hz.

[0089] By connecting the extension section 302 of the sand accumulation tube 301, the bottom of each sand accumulation tube 301 is extended to both sides, changing the spatial layout of the sand accumulation box 306 from one column to four columns. This increases the space for placing the sand accumulation boxes 306. Compared with the traditional "wind erosion wind tunnel sand collector," the diameter of the sand accumulation box 306 increases from 2cm to 6-7cm, greatly expanding the capacity and bottom space of the sand accumulation box 306. In addition, an automatic weighing system is installed at the bottom of each sand accumulation box 306. Compared with the wind erosion wind tunnel sand collector, it achieves automatic acquisition of sand transport profile time series data for a longer period of time, and has the advantages of large capacity and long standby time. The inclined connecting section 106 of the sand collector, that is, the extension section 302 of the sand accumulation tube 301, extends to both sides, and its length does not change with the height of the sand accumulation tube 301. Compared with the traditional "wind erosion wind tunnel sand collector," there is no data delay effect, so the automatic data acquisition is highly accurate.

[0090] Existing sand-collecting instruments require manual weighing of the sand in each collection box 306 after a sand transport experiment at a given wind speed. All collection boxes 306 must then be emptied, the sand-collecting instrument reinstalled, and the experiment continued at the next wind speed. This process is cumbersome, time-consuming, and labor-intensive. For example, in wind tunnel simulation experiments during sand transport, wind speeds are typically set to six groups (6, 8, 10, 12, 14, and 16 m / s). Each group of wind speeds involves multiple steps, including erosion, weighing, and reinstalling the sand-collecting instrument, taking approximately 20 minutes. Therefore, the total experimental process for one sample requires at least two hours. Furthermore, prolonged erosion of the bed surface can cause it to drop, necessitating continuous replenishment of sediment during the experiment to maintain the bed surface flush with the wind tunnel floor 501, which also wastes time.

[0091] The fully automatic sand transport profile testing unit 30 provided in this embodiment of the invention does not require multiple manual weighings and re-layouts during the experiment. It only requires setting up the bed surface once. When the sand transport experiment at one wind speed ends, the wind speed can be increased to the next target wind speed. The erosion time for each wind speed is 20-60 seconds. The total experiment for one sample can be completed within 2-5 minutes. The entire experimental process realizes automatic and continuous acquisition and recording of sand transport at different heights.

[0092] Therefore, this invention streamlines the collection of sediment transport profile data under different wind speeds for the same sediment, simplifies experimental procedures, reduces the experimental time from 2 hours to 5 minutes, significantly saves labor and time costs, and improves experimental efficiency. The time-series sediment transport profile data also enables detailed capture and precise analysis of the transport process.

[0093] The fully automatic sand transport profile testing unit 30 provided in this embodiment of the invention preferably uses a sand transport rate acquisition frequency of 100Hz, which is consistent with the acquisition frequency of particle impact number and kinetic energy, as well as wind speed profile, from the wind erosion sensor. By synchronizing the sand transport profile time series data with sand particle mass, quantity, kinetic energy, and frictional wind speed, the interaction between particles and the bed surface in the sand flow can be captured more accurately. If used in conjunction with meteorological instruments, the feedback relationship between the sand transport rate and meteorological elements (such as air temperature, humidity, and atmospheric pressure) can also be analyzed and interpreted. These functions are not available in previous gradient-type sand accumulation instruments that used manual weighing or low-frequency acquisition (1Hz).

[0094] See also Figure 9 In some implementations, the fully automatic wind speed testing unit 40 includes a sand table 401, on which multiple test units are arranged separately from each other. Each test unit includes a sand-laying section 402, a narrowing section 403, a shooting channel 404, and a sand collection trough 405 arranged sequentially along the wind direction. The sand-laying section 402 is used to lay experimental sand. The widths of the sand-laying section 402, the narrowing section 403, and the shooting channel 404 decrease sequentially. The shooting channel 404 has a shooting area corresponding to the miniature high-speed camera 407. The sand collection trough 405 has a V-shaped bottom, and sand particle identification areas 406 are distributed on the V-shaped bottom.

[0095] In some embodiments, a magnifying glass 411 is also connected to the lower part of the sand collection tank 405, and the magnifying glass 411 is set corresponding to the sand identification area 406;

[0096] In some implementations, the V-shaped groove bottom is formed by assembling ultra-white glass with a light transmittance of >93%.

[0097] In some embodiments, the sand table 401 is provided with a plurality of vertical partitions and / or sand scrapers 408; the plurality of vertical partitions are spaced apart from each other, thereby dividing the sand table 401 into a plurality of test units; the sand scrapers 408 are used to smooth the sand surface of the test sand laid on the plurality of sand-laying sections 402.

[0098] In some implementations, the wind erosion particle starting wind speed testing device further includes an upwind extension section 409302, and the upwind extension section 409302 and the sand table 401 are arranged sequentially along the wind direction;

[0099] In some embodiments, the wind erosion particle-initiated wind speed testing device further includes a lifting platform 410 connected to the sand table 401.

[0100] In some implementations, during operation, the wind erosion particle initiation wind speed testing device is set in the test section 105, and the sand surface of the test sand in each sand-laying section 402 is on the same horizontal plane as the surface of the bottom plate 501 of the test section 105, the surface of the upwind extension section 409302, and the bottom surface of each vertical partition. The leading edge of the wind erosion particle initiation wind speed testing device is seamlessly connected to the bottom plate 501 of the wind tunnel.

[0101] In some embodiments, the two ends of the sand scraper 408 are set on the vertical partition, and the bottom edge is located on the sand surface of the experimental sand in the multiple sand-laying sections 402; and / or, the sand tray 401 is a rectangular sunken structure with a length of 70cm, a width of 30-45cm, and a depth of 4cm; and / or, the length of the sand-laying section 402 is 70cm and the width is 10-15cm; and / or, one end of the narrowing section 403 has a width equal to that of the corresponding sand-laying section 402, and the other end has a width equal to that of the corresponding shooting channel 404, and a length of 8cm; and / or, the length of the shooting channel 404 is 12cm and the width is 3-5cm; and / or, the height of the vertical partition is 3cm; and / or, the shooting area is a circular area with a radius of 3-5cm; and / or, the length of the upwind extension section 409302 is 5cm and the width is 30-45cm.

[0102] In some embodiments, the upper ends of the scraper 408 are provided with two angles that cooperate with the vertical partition along the horizontal direction. The upper end of the scraper 408 has a length of 14-19cm, the lower end has a length of 10-15cm, and the total height is 5cm. The protruding length of the angle is 2cm and the height is 2cm.

[0103] In some embodiments, a magnifying glass 411 is also connected to the lower part of the sand collection trough 405, and the magnifying glass 411 is set corresponding to the sand identification area 406; and / or, the sand identification area 406 is a linear area; and / or, the top opening of the sand collection trough 405 has a length of 15cm, a width of 10-15cm, and a depth of 30cm; and / or, the sand collection trough 405 is a V-shaped trough; and / or, the angle of the bottom of the sand collection trough 405 is 30°; and / or, the bottom of the V-shaped trough is formed by assembling ultra-white glass with a light transmittance >93%.

[0104] In some implementations, a camera bracket 412 is also included for mounting the miniature high-speed camera 407 above the corresponding shooting area.

[0105] In some implementations, the vertical distance between the miniature high-speed camera 407 and the shooting area is 5-10 cm, and the lens of the miniature high-speed camera 407 is pointed downwards at the corresponding shooting area.

[0106] In some implementations, the fully automated wind erosion experimental system further includes a gradient Pitot tube 413, which is connected to a data acquisition instrument 414 and a computer 415. The gradient Pitot tube 413 is set at the center axis of the experimental section 105, which is 1-3m away from the windward edge of the sand table 401, and is used to measure the wind speed at multiple heights.

[0107] In some typical implementation cases, at the initial start-up, the sand particles have a low velocity and are basically in a low-lying motion. Almost all the sand particles fall into the V-shaped sand collection tank 405 and are concentrated in the linear area of ​​the identification zone 406 at the bottom of the V-shaped tank. The high-transparency ultra-white glass and the 10x rectangular magnifying glass 411 make it easy for the observer to spot the sand particles at the bottom of the tank. When a few sand particles are found at the bottom of the tank, the exact time at this moment is recorded as the start-up time. Based on this start-up time, the corresponding start-up wind speed value is found from the time-series wind speed data, or the start-up friction wind speed value is calculated based on the wind speed gradient data. Compared with the human eye directly observing the start-up process of sand particles on the bed surface, this method has the advantages of easy identification and high accuracy. Therefore, the experimental results are more objective, and it basically solves the defects encountered in various current measurement methods. It provides a scientific and practical new device for accurately defining the start-up wind speed of sand particles in a wind tunnel.

[0108] In some typical implementation cases, the tapering design of the vertical partition of the sand table 401 allows a small number of sand grains to pass through the narrow shooting channel 404 in a concentrated manner, increasing the number of moving sand grains per unit area in the shooting area. This makes it easier to identify moving sand grains in the image playback, increases the probability of identifying sand grains in the image at the moment of passing through, improves the accuracy of the start-up time definition, and consequently improves the accuracy of the start-up wind speed value.

[0109] In some typical implementation cases, the test units separated by the vertical partition of the sand table 401 correspond to each independent high-speed camera and V-shaped collection trough in the downwind direction. This design makes the test units, movement paths and observation and identification systems of different types of sand particles completely independent and do not interfere with each other, thereby achieving synchronous and accurate observation of the starting wind speed of various particles.

[0110] In some typical implementation cases, wind erosion initiation experiments of multiple sets of sediments can be carried out simultaneously. Since the experiments are conducted simultaneously, synchronously, and on the same sand table 401, the boundary conditions, including minor fluctuations in wind speed on the sand bed surface, are almost identical. In particular, for the determination of impact initiation wind speed under upwind sand supply conditions, it can be ensured that the concentration and energy of the impact sand particles acting on the bed surface are basically the same, thus the results are more accurate. Since multiple sets of sediments are tested simultaneously, the bed surface only needs to be set up once to complete the determination of the initiation wind speed of various particles, thus avoiding repeated bed surface setup, shortening the experimental time, and improving the time efficiency of this type of experiment. In addition, when the initiation time values ​​obtained from the image and the V-shaped observation trough are inconsistent, the smaller value is taken as the final result, realizing the synchronous application of the two observation methods, which plays a double insurance effect of mutual supplementation and verification.

[0111] See also Figures 10-12 In some implementations, the telescopic sand table testing unit 50 includes a base plate 501, a plurality of transverse embedded tracks 502 symmetrically arranged on the upper surface of the base plate 501, a plurality of longitudinal embedded tracks 503, a plurality of transverse slide rods 504 having various lengths, longitudinal slide rods 505, and slide rod bases 506.

[0112] The bottom of the slide base is slidably engaged with the horizontal embedded rail 502 or the vertical embedded rail 503, and the top is engaged with the horizontal slide bar or the vertical slide bar.

[0113] Among them, multiple lengths refer to one of the lengths of the transverse slide bar being equal to the width of the experimental sand table required for a certain wind erosion experiment.

[0114] In some typical implementation cases, the embedded track consists of three horizontal embedded tracks 502 and two vertical embedded tracks 503. Its cross-section is an "I-shaped" aluminum profile with a height of 2-3 cm and a width of 2-3 cm. The embedded track is installed on the base plate 501 of the experimental section 105, with the top surface of the embedded track flush with the surface of the base plate 501.

[0115] The sliding rods consist of two longitudinal sliding rods 505 and two transverse sliding rods 504, all of which are rectangular aluminum profile columns with a cross-sectional height of 3-5cm and a cross-sectional width of 2-3cm, thus the sand bed depth is 3-5cm. The bottom surface of the sliding rod is concave in the middle, and the two sides of the bottom surface are flush with the bottom plate 501 of the experimental section 105.

[0116] The top of the slide base 506 is a protruding cuboid structure that can be inserted into the recessed part of the bottom surface of the slide rod. Its concave and convex shape matches, allowing the slide rod to slide freely on the slide base 506. The bottom cross-section of the slide base 506 is a "T"-shaped concave shape that matches the upper half of the embedded track, allowing it to slide freely on the embedded track.

[0117] In some typical implementation cases, the length of the base plate 501 of test section 105 is determined according to the specifications of test section 105, generally 1.2-3m, therefore the length of the longitudinal sliding rod 505 is 1-2.5m. When the required length of the experimental sand table is greater than 2.5m, one or more telescopic sand table test units can be added to the upwind or downwind direction of the original telescopic sand table test unit, so that the length of the experimental sand table reaches 1-10m. This length of the experimental sand table meets the needs of most wind erosion experiments.

[0118] In some typical implementation cases, the width of the base plate 501 of experimental section 105 is determined according to the specifications of experimental section 105, generally ranging from 60 to 120 cm. The length of the transverse sliding rod 504 varies from 20 cm to the width of experimental section 105, thus the length of the transverse sliding rod 504 ranges from 20 to 120 cm, and is divided into 11 length specifications in 10 cm intervals: 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 cm. The width of the sand table used in this experiment can meet the needs of most experimental section 105 widths and wind erosion experiments.

[0119] See also Figure 13 In some implementations, the base plate 501 is provided with an openable and closable sand outlet 507.

[0120] In some implementations, a sealing disc 508 is used to seal the sand leakage port 507. The sealing disc 508 is rotatably connected to the side of the sand leakage port 507 via a fixed shaft 509. When the sealing disc 508 rotates horizontally about the fixed shaft 509, the sand leakage port 507 can be changed from a closed state to an open state.

[0121] The steps for conducting the experiment using the above implementation scheme include: First, moving the two longitudinal sliding rods 505 so that their distance reaches the designed width of the experimental sand table in the experimental scheme, and installing the transverse sliding rod 504 matching this width; Second, the length of the experimental sand table can be reduced by sliding the longitudinal sliding rods 505 downwind, and increased by sliding the longitudinal sliding rods 505 upwind. One or more of the telescopic sand table test units 50 can also be added upwind or downwind of the telescopic sand table test unit to further extend the length of the experimental sand table to reach the designed length in the experimental scheme; Then, at the sand accumulation instrument installation port 510, the fully automatic sand conveying profile test unit 30 of this invention or other types of test units are set up. After laying the sand surface, the experiment begins. After the experiment is completed, the leak-proof disc 508 is rotated to open the leak port 507, and the sand particles in the experimental sand table are cleaned, completing the entire experimental process.

[0122] Based on the above technical solution, the telescopic sand table testing unit 50 provided by this invention can adjust the length and width of the experimental sand table according to the differences in parameters such as the type, quantity, particle size, erosion time, and surface humidity of the sediment sample. This achieves flexible adjustment of the length and width of the experimental sand table in the wind tunnel, meeting the needs of most wind erosion wind tunnels and wind erosion experiments. Before each experiment, adaptive adjustments can be made according to the specific process or object being simulated, without the need to remake or modify the experimental sand table. Simply slide the slider to adjust the experimental sand table to the appropriate length and width. This saves on experimental material, labor, and time costs, and increases experimental efficiency. It can be reused for a long time and is suitable for simulating most wind erosion processes, such as initiation, transmission, abrasion, and wind erosion landforms, as well as most wind-eroded sediments.

[0123] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-speed wind erosion wind tunnel, comprising a wind tunnel body and a power unit; The wind tunnel body includes a power section, a diffusion section, a rectification section, a contraction section, and an experimental section connected sequentially along the internal gas flow direction. The power unit is located in the power section and is used to generate flowing gas. Its features are, The power unit includes a turbocharger, an exhaust mechanism, and an airfoil structure. The exhaust mechanism connects the turbocharger and the power section, and causes the compressed gas provided by the turbocharger to flow through the surface of the airfoil structure in a direction deflected or toward the internal gas flow direction before circulating into the power section. The wind tunnel body includes a direct-flow blowing structure or a circulating blowing structure; The DC blowing structure also includes a connecting section disposed between the power section and the diffusion section, and the power section, connecting section, diffusion section, rectifier section, contraction section and experimental section are connected sequentially in a straight line direction; The circulating air-blowing structure also includes a sand accumulation section located after the experimental section. The power section, diffusion section, rectification section, contraction section, experimental section, and sand accumulation section are connected end to end in a rectangle, and a turning connection section is provided at the junction of any two sides of the rectangle.

2. The high-speed wind erosion wind tunnel according to claim 1, characterized in that, The air outlet mechanism includes an annular air duct connected to the turbocharger fan and an annular air outlet disposed on the inner surface of the annular air duct. The annular air passage has an airfoil-shaped cross-sectional shape on at least a portion of the inner surface of the side facing the annular air outlet to form the airfoil structure.

3. The high-speed wind erosion wind tunnel according to claim 2, characterized in that, The rated power of the turbocharger is 200-500kw, and the power unit also includes a frequency converter electrically connected to the turbocharger, the frequency conversion range of which is 0-50Hz.

4. The high-speed wind erosion tunnel according to claim 2, characterized in that, The power unit includes a heating device for regulating the temperature of the compressed air entering the power section; The heating device includes an annular ceramic heating wire disposed in the annular air passage.

5. The high-speed wind erosion wind tunnel according to claim 4, characterized in that, The power unit includes a gas generator for adjusting the composition of the compressed air; The gas generator includes one or more combinations of a carbon dioxide generator, a nitrogen generator, an oxygen generator, and a humidified air generator.

6. A fully automated wind erosion testing system, characterized in that, Includes the high-speed wind erosion wind tunnel and testing components as described in any one of claims 1-5; The test components include: The fully automated sand transport profile testing unit is used at least to measure the time series data of the sand transport profile within the experimental section. And / or, the fully automatic start-up wind speed test unit is used to at least determine the start-up wind speed of the sediments in the test section; And / or, a telescopic sand table testing unit with adjustable length and width.

7. The fully automated wind erosion testing system according to claim 6, characterized in that, The fully automatic test unit for the sand transport profile includes multiple sand accumulation collection components, which include a sand accumulation pipe, an extension section, a sand accumulation bucket, an electronic scale, and a data acquisition instrument. The first end of the sand collection pipe extends horizontally and has an opening. The extended section is connected to the second end of the sand collection pipe and extends toward the sand collection bucket so that the sand collected by the sand collection pipe can fall into the sand collection bucket. The openings of the multiple sand-collecting pipes are distributed at different heights; The electronic scale is positioned below the sand collection bucket and is used to weigh the mass of sand and dust inside the sand collection bucket. The data acquisition instrument is electrically connected to the electronic scale and is used at least to record the weighing value of the electronic scale in real time.

8. The fully automated wind erosion testing system according to claim 7, characterized in that, The sand collection component also includes a sand collection box and a sand collection cover. The sand collection cover is fastened to the opening of the sand collection box to prevent sand and dust from entering the sand collection box without passing through the sand collection pipe. The sand collection pipe passes through the sand collection cover and is arranged in a straight line. The extension section includes an inclined portion, so that the sand collection buckets are arranged alternately left and right along the plane formed by the sand collection pipe, and the lengths of the inclined portions of the multiple extension sections are all equal. The fully automated wind erosion experimental system also includes a wind erosion sensor and / or a wind speed profile sensor, and the data acquisition instrument has an acquisition frequency of 1-100Hz, which is consistent with the acquisition frequency of the wind erosion sensor and / or the wind speed profile sensor.

9. The fully automated wind erosion testing system according to claim 6, characterized in that, The fully automatic starting wind speed testing unit includes a sand table with multiple test units separated from each other. Each test unit includes a sand-laying section, a narrowing section, a shooting channel, and a sand collection trough arranged sequentially along the wind direction. The sand-laying section is used to lay experimental sand. The widths of the sand-laying section, the narrowing section, and the shooting channel decrease sequentially. The shooting channel has a shooting area corresponding to a miniature high-speed camera. The sand collection trough has a V-shaped bottom with sand particle identification areas distributed on the bottom. And / or, a magnifying glass is also connected to the lower part of the sand collection tank, and the magnifying glass is set in relation to the sand identification area; And / or, the V-shaped groove bottom is formed by assembling ultra-white glass with a light transmittance of >93%.

10. The fully automated wind erosion testing system according to claim 6, characterized in that, The telescopic sand table testing unit includes a base plate, multiple horizontal embedded tracks symmetrically arranged on the upper surface of the base plate, multiple vertical embedded tracks, multiple horizontal slide bars of various lengths, vertical slide bars, and slide bar bases. The bottom of the slide rod base is slidably engaged with the horizontal or vertical embedded track, and the top is engaged with the horizontal or vertical slide rod. The base plate is equipped with an openable and closable sand leakage port.

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