A device and method for accurately measuring air volume in a cross section of an underground tunnel

Abstract

The present invention discloses a device for accurately measuring the cross-sectional air volume of an underground tunnel, comprising a slide rail assembly, a moving assembly, a measuring assembly, a connecting rod and a connecting piece. The moving assembly is movably assembled on the slide rail assembly, the measuring assembly is assembled on the lower end of the moving assembly, the moving assembly and the measuring assembly, and the measuring assemblies are connected via connecting rods and connecting pieces, the connecting rods are rotatably assembled on the connecting pieces, and a method for accurately measuring the cross-sectional air volume of an underground tunnel is also disclosed. When calculating the cross-sectional area of ​​the tunnel section, the present invention adopts a calculation method combining a polygonal area formula with an integral method, which can obtain more accurate results. In the process of measuring and calculating the air volume, the influencing factors of the roughness of the tunnel wall are taken into consideration, so that the air volume and pressure loss of the tunnel can be calculated more accurately, and finally a more accurate air volume result can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind speed and volume monitoring in underground tunnels, and in particular provides a device and method for accurately measuring the cross-sectional wind volume in an underground tunnel. Background Art

[0002] Mine ventilation is the premise for ensuring safe production in mines, and the measurement of wind speed and air volume in underground tunnels is a key technical link to ensure mine ventilation safety. However, due to the complex and irregular cross-sectional shape of the tunnel, traditional air volume measurement methods generally rely on single-point wind speed measurement and assume an ideal cross-sectional shape for estimation. This method has low accuracy and is prone to large errors. It cannot meet the needs of accurate air volume monitoring in complex tunnels, increasing the risk of underground operations.

[0003] In recent years, the application of multi-point wind speed technology in underground monitoring has shown great potential. Laser scanning technology can generate high-precision point cloud data of tunnel sections, which is used to accurately depict complex cross-sectional shapes, and multi-point wind measurement technology can capture wind speed distribution in different areas. The organic combination of these technologies can achieve more comprehensive wind speed and air volume monitoring, which can significantly improve the accuracy of wind volume measurement. However, there is currently a lack of a mature system and method to more effectively integrate cross-sectional shape and wind speed distribution data to achieve fast and effective wind speed and air volume precision measurement. In the existing technology, wind speed sensors are mostly installed on the wall of the tunnel, there are errors in measurement, and multi-point wind measurement and tunnel section roughness identification cannot be achieved. In addition, in the design of the ventilation system of the mine tunnel, the airflow in the tunnel will be affected by factors such as wall roughness, tunnel morphology, and flow velocity, which will affect the measurement and calculation of air volume, especially when facing irregular sections or complex tunnel environments. This problem becomes particularly complicated.

[0004] Based on this, the present invention proposes an underground tunnel cross-section air volume precision measurement device and method, provides a high-precision air volume measurement solution, effectively improves the data reliability and real-time performance of underground ventilation management, and provides technical support for safe operation of mines. Combined with the ventilation optimization system, air is supplied on demand to achieve energy conservation and emission reduction in mines. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a device and method for accurately measuring the cross-sectional air volume of an underground tunnel.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an underground tunnel cross-section air volume precision measuring device, comprising a slide rail assembly, a moving assembly, a measuring assembly, a connecting rod and a connecting piece, wherein the moving assembly is movably assembled on the slide rail assembly, the measuring assembly is assembled on the lower end of the moving assembly, the moving assembly and the measuring assembly, and the measuring assemblies are connected by connecting rods and connecting pieces, and the connecting rods are rotatably assembled on the connecting piece;

[0007] The slide rail assembly includes a mounting plate and an arc-shaped rack, the arc-shaped rack is fixedly mounted on the lower surface of the mounting plate, and the front and rear surfaces of the arc-shaped rack are both provided with guide grooves;

[0008] The moving assembly includes a moving box body, a moving gear and a limiting assembly, wherein the moving gear is rotatably assembled in the moving box body, and the moving gear is meshed with an arc-shaped rack, and two limiting assemblies are symmetrically rotatably assembled on the front and rear surfaces of the inner cavity of the moving box body, and the inner ends of the limiting assemblies are inserted into the guide slide grooves;

[0009] The measuring component is equipped with a laser scanning module and a wind speed detection module.

[0010] Furthermore, the limiting assembly includes a rotating shaft, a circular plate, a sliding rod and a limiting ring. The front and rear surfaces of the movable box body are provided with circular holes, and the rotating shaft is inserted into the circular holes. A circular plate is fixedly installed on the inner end of the rotating shaft, and a sliding rod is fixedly installed on the inner surface side of the circular plate, and the sliding rod is inserted into the guide groove. The two limiting rings are screwed to the outer surface of the rotating shaft, and the two limiting rings are respectively located on the inner and outer sides of the movable box body.

[0011] Furthermore, a moving motor is fixedly mounted on the rear surface of the moving box body, and a moving gear is fixedly mounted on an output shaft of the moving motor, and a motor protection shell is mounted on the outer side of the moving motor.

[0012] Furthermore, through slots are provided on the left and right surfaces of the movable box body, and the arc-shaped rack passes through the through slots.

[0013] Furthermore, a fixing plate is fixedly mounted on the lower surface of the movable box body, and an electric push rod is fixedly mounted on the lower surface of the fixing plate in a left-right symmetrical manner.

[0014] Furthermore, positioning blocks are symmetrically fixedly installed on the left and right surfaces of the measuring component, and threaded holes are formed on the upper surfaces of the positioning blocks.

[0015] Furthermore, a round block is fixedly mounted on one end of the connecting rod and the output end of the electric push rod, and a thread matching the threaded hole is provided on the other end of the connecting rod. The diameter of the connecting rod is the same as the diameter of the output end of the electric push rod.

[0016] Furthermore, the connecting piece includes a semi-cylinder, two of the semi-cylinders are spliced ​​to form a cylindrical structure, the upper and lower end faces of the semi-cylinder are provided with slots matching the connecting rod, the inner surfaces of the semi-cylinder are provided with semi-cylindrical grooves connected to the inner ends of the slots, and the diameter of the semi-cylindrical grooves is the same as the diameter of the round block.

[0017] A method for accurately measuring the cross-sectional air volume of an underground tunnel, using the above-mentioned accurate cross-sectional air volume measurement device for an underground tunnel, specifically comprises the following steps:

[0018] Step 1: Install the device. Hang the slide rail assembly on the top plate of the tunnel, install the moving assembly on the slide rail assembly, mesh the moving gear with the arc rack, insert the slide bar into the guide slot, and then install a set of measuring components under the moving assembly.

[0019] Step 2, during the measurement process, the moving motor is operated to drive the moving component and the measuring component to move from one end of the slide rail component to the other end, and at the same time, the electric push rod is operated to drive the measuring component to move in the vertical direction, so that the measuring component measures the wind speed data on the same horizontal plane;

[0020] During the movement of the mobile component, the mobile component stops when it is at the leftmost position, the middle position, and the rightmost position. At this time, the laser scanning module performs a 360° rotation scan on the tunnel, and the cross-sectional data obtained at the leftmost position, the middle position, and the rightmost position are recorded as A1, A2, and A3, respectively. At the same time, the wind speed detection module detects the wind speed in the tunnel in real time, and the wind speed data obtained at the leftmost position, the middle position, and the rightmost position are v1, v2, and v3, respectively, and all the data are transmitted to the host for calculation and analysis;

[0021] Step 3: Calculate the average wind speed on the cross section based on the wind speed data at each point. Use the weighted average method to average the wind speed data measured by the wind speed detection module according to the weighted position. The formula for the weighted average wind speed is:

[0022] ;

[0023] in, is the weighted mean wind speed, v i is the wind speed measured by the wind speed detection module;

[0024] Step 4: Obtain the point cloud coordinates. Assume that the laser scanning module generates n points of the tunnel cross-section contour by scanning, represented as (x1, y1), (x2, y2), ..., (x n ,y n ), these points are connected in sequence to form a closed polygon;

[0025] Step 5, the first calculation method of the closed polygon uses the polygon area formula. For irregular closed polygons, the calculation formula for the cross-sectional area S1 in Algorithm 1 is:

[0026] ;

[0027] Among them, (x i ,y i ) and (x i+1 ,y i+1 ) represents the coordinates of two adjacent points, and N is the number of sides of the closed polygon;

[0028] Step 6, the second calculation method of the closed polygon uses the integral method to triangulate the closed polygon to obtain multiple small triangles. The area of ​​each small triangle is calculated and summed to obtain the total area of ​​the cross section. The calculation formula of the cross-sectional area S2 of Algorithm 2 is:

[0029] ;

[0030] Among them, S k is the area of ​​the kth small triangle, and m is the number of small triangles obtained by dissection;

[0031] Step 7, coupling the two tunnel cross-sectional area algorithms of step 5 and step 6 to obtain the accurate cross-sectional area S3 of the tunnel section;

[0032] Step 8: Calculate the preliminary cross-sectional wind volume based on the weighted average wind speed and precise cross-sectional area S3, the calculation formula for the preliminary cross-sectional air volume Q1 is:

[0033] ;

[0034] Step 9: Friction loss of tunnel air volume, including the effect of average roughness on airflow, local flow loss and further effect of irregular cross-section on airflow;

[0035] The friction loss formula is as follows:

[0036] ;

[0037] Where ΔP is the pressure loss, f is the overall friction coefficient, L is the tunnel length, D is the tunnel diameter, ρ is the gas density, and v c is the gas flow velocity;

[0038] Correct and adjust the above formula;

[0039] For roadways, the wall roughness It directly affects the overall friction coefficient f, which is expressed by the following implicit equation:

[0040] ;

[0041] ;

[0042] in, is the wall roughness, Re is the Reynolds number of the airflow, which represents the ratio of the inertia to the viscosity of the airflow, and u is the dynamic viscosity of the gas;

[0043] The local flow resistance coefficient K is introduced for correction, and the calculation formula of the local flow resistance is obtained as follows:

[0044] ;

[0045] Where ΔP local is the local flow resistance, K is the local flow resistance coefficient;

[0046] CFD simulation technology was introduced. CFD is computational fluid dynamics. A three-dimensional grid was established to accurately calculate the flow path, velocity field, pressure field of the airflow in the tunnel and the interaction with the tunnel wall, and the following formula was obtained:

[0047] ;

[0048] Where ΔP total is the overall flow resistance of the tunnel, f is the overall friction coefficient, and f local is the local friction coefficient, K i is the flow resistance coefficient at a local location in the tunnel, L j is the length of the roadway at the irregular section location, D j is the tunnel diameter at the irregular section location, v j is the gas flow velocity at the irregular section position, i is the local position in the tunnel, j is the local position of the irregular section, the first term considers the effect of average roughness on the gas flow, the second term is the local flow loss, and the third term considers the further effect of the irregular section on the gas flow;

[0049] Step 10, calculate the cross-sectional air volume. Combining steps 8 and 9, the precise cross-sectional air volume Q is calculated as:

[0050] .

[0051] The beneficial effects of using the present invention are:

[0052] The present invention designs a slide rail assembly and a moving assembly, which can effectively move the measuring assembly to different positions in the tunnel to complete tunnel section scanning and wind speed measurement at different positions. At the same time, with the assistance of the electric push rod, the measuring assembly can maintain a horizontal state during the movement, thereby improving the accuracy of the wind speed measurement.

[0053] The present invention designs the structure of the moving component so that it can always maintain a vertical state when moving along the arc-shaped rack, further ensuring the horizontal movement of the measuring component during the moving process and further improving the accuracy of the measurement.

[0054] The present invention also designs connecting rods and connecting parts, so that the measuring component can be easily installed on the mobile component, and supports the series connection of multiple measuring components, so that multi-point measurement can be performed at different positions of the same section, and multiple groups of data at different positions can be obtained at the same time, avoiding data changes caused by using one measuring component for multiple measurements, and improving the accuracy of the measurement.

[0055] When calculating the cross-sectional area of ​​the tunnel section, the present invention adopts a calculation method combining the polygon area formula with the integral method, which can obtain a more accurate result.

[0056] In the process of measuring and calculating the air volume, the present invention takes into account the influencing factors of the roughness of the tunnel wall, and can more accurately calculate the air volume and pressure loss of the tunnel, and finally obtain a more accurate air volume result. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is one of the three-dimensional schematic diagrams of the present invention.

[0058] Figure 2 This is the second stereoscopic schematic diagram of the present invention.

[0059] Figure 3 It is a partial cross-sectional view of the assembly of the moving assembly and the slide rail assembly of the present invention.

[0060] Figure 4 It is a three-dimensional schematic diagram of the mobile assembly of the present invention.

[0061] Figure 5 It is a three-dimensional schematic diagram of the connecting piece of the present invention.

[0062] Figure 6 It is a cross-sectional view of the connecting piece of the present invention.

[0063] Figure 7 It is a three-dimensional schematic diagram of embodiment 3 of the present invention.

[0064] Reference numerals include:

[0065] 1. Slide rail assembly, 11. Mounting plate, 12. Arc rack, 13. Guide slide groove, 2. Moving assembly, 21. Moving box body, 22. Moving motor, 221. Motor protection shell, 23. Moving gear, 24. Limiting assembly, 241. Rotating shaft, 242. Round plate, 243. Slide rod, 244. Limiting ring, 25. Through groove, 26. Fixed plate, 27. Electric push rod, 3. Measuring assembly, 31. Laser scanning module, 32. Wind speed detection module, 33. Positioning block, 4. Connecting rod, 5. Connecting piece, 51. Semi-cylinder, 52. Slot, 53. Semi-cylindrical groove. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Embodiment 1

[0068] Reference Figures 1 to 6 A device for accurately measuring the cross-sectional air volume of an underground tunnel comprises a slide rail assembly 1, a moving assembly 2, a measuring assembly 3, a connecting rod 4 and a connecting piece 5. The moving assembly 2 is movably assembled on the slide rail assembly 1, the measuring assembly 3 is assembled on the lower end of the moving assembly 2, the moving assembly 2 and the measuring assembly 3, and the measuring assemblies 3 are connected via the connecting rod 4 and the connecting piece 5, and the connecting rod 4 is rotatably assembled on the connecting piece 5.

[0069] The slide rail assembly 1 is installed on the tunnel roof. In this embodiment, an arc-shaped rack 12 is used. A straight rack or an arc-shaped rack with other curvatures can be selected according to actual conditions.

[0070] The slide rail assembly 1 comprises a mounting plate 11 and an arc-shaped rack 12 . The arc-shaped rack 12 is fixedly mounted on the lower surface of the mounting plate 11 . The front and rear surfaces of the arc-shaped rack 12 are both provided with guide grooves 13 .

[0071] like Figure 4 As shown, the moving assembly 2 includes a moving box body 21, a moving gear 23 and a limit assembly 24. The moving gear 23 is rotatably assembled in the moving box body 21, and the moving gear 23 is meshed with the arc-shaped rack 12. The two limit assemblies 24 are symmetrically rotatably assembled on the front and rear surfaces of the inner cavity of the moving box body 21, and the inner end of the limit assembly 24 is inserted into the guide groove 13.

[0072] The moving motor 22 drives the moving gear 23 to rotate, and under the action of meshing, it can drive the moving component 2 to move, and then drive the measuring component 3 to move.

[0073] The measuring component 3 is equipped with a laser scanning module 31 and a wind speed detection module 32 .

[0074] The laser scanning module 31 is used to scan the cross-sectional area of ​​the tunnel section, and the wind speed detection module 32 is used to measure the wind speed. The data obtained by the two can be used to obtain the wind volume after calculation.

[0075] The measuring device is also provided with a power supply module, an infrared remote control module, a control module, a communication module, a central processing module and a display module.

[0076] The power supply module is composed of a mobile power supply and an underground circuit, which respectively supplies power to the mobile component 2 and the measuring component 3.

[0077] The infrared remote control module is installed on the mobile component 2, and the mobile motor 22 and the electric push rod 27 on the mobile component 2 can be remotely controlled at the mobile end, making the operation more convenient and quick.

[0078] The control module is the moving motor 22 and the electric push rod 27, which are used to control the positions of the moving component 2 and the measuring component 3.

[0079] The communication module is used to realize CAN, wired and wireless transmission, and can transmit the measured and calculated wind speed, wind volume and other information to the display terminal or mobile terminal.

[0080] The central processing module is set on an external host and is used to accurately analyze and calculate the collected data to achieve fast and efficient processing that can be used immediately. At the same time, the central processing module can control the actions and measurements of other modules in real time as required.

[0081] The display module is provided on the host, the mobile terminal and the measuring component 3, and can display information such as wind speed, air volume, cross-sectional area, cross-sectional roughness, wind resistance, etc., and can also display the precise cross-sectional profile on the screen.

[0082] Specifically, if Figure 3 and Figure 4 As shown, the limiting assembly 24 includes a rotating shaft 241, a circular plate 242, a sliding rod 243 and a limiting ring 244. The front and rear surfaces of the movable box body 21 are provided with circular holes, and the rotating shaft 241 is inserted into the circular holes. The inner end of the rotating shaft 241 is fixedly installed with a circular plate 242, and the inner surface side of the circular plate 242 is fixedly installed with a sliding rod 243, and the sliding rod 243 is inserted into the guide groove 13. Two limiting rings 244 are screwed to the outer surface of the rotating shaft 241, and the two limiting rings 244 are respectively located on the inner and outer sides of the movable box body 21.

[0083] Specifically, if Figure 3 As shown, a moving motor 22 is fixedly mounted on the rear surface of the moving box body 21 , and a moving gear 23 is fixedly mounted on the output shaft of the moving motor 22 . A motor protection shell 221 is installed on the outer side of the moving motor 22 to protect the moving motor 22 .

[0084] Specifically, through slots 25 are formed on the left and right surfaces of the moving box body 21 , and the arc-shaped rack 12 passes through the through slots 25 .

[0085] Specifically, if Figure 4 As shown, a fixing plate 26 is fixedly mounted on the lower surface of the moving box body 21 , and an electric push rod 27 is fixedly mounted on the lower surface of the fixing plate 26 in a left-right symmetrical manner.

[0086] Specifically, positioning blocks 33 are symmetrically fixedly installed on the left and right surfaces of the measuring component 3 , and threaded holes are formed on the upper surfaces of the positioning blocks 33 .

[0087] Specifically, a round block is fixedly mounted on one end of the connecting rod 4 and the output end of the electric push rod 27 , and a thread matching the threaded hole is provided on the other end of the connecting rod 4 . The diameter of the connecting rod 4 is the same as the diameter of the output end of the electric push rod 27 .

[0088] The output end of the electric push rod 27 is rotatably assembled with the upper end of the connecting piece 5, the lower end of the connecting piece 5 is rotatably assembled with one end of the round block of the connecting rod 4, and the threaded end of the connecting rod 4 is screwed into the threaded hole on the positioning block 33 to realize the installation of the measuring component 3, wherein the operation of the electric push rod 27 can adjust the height of the measuring component 3.

[0089] The threaded hole below the positioning block 33 can continue to be used to install the connecting rod 4. After the connecting piece 5 and the connecting rod 4 are connected in sequence downward, another measuring component 3 can be installed. Therefore, when actually measuring, multiple measuring components 3 can be installed at the same time to perform measurement work at different positions in the tunnel.

[0090] Specifically, if Figure 5 and Figure 6 As shown, the connecting member 5 includes a semi-cylinder 51, and two semi-cylinders 51 are spliced ​​to form a cylindrical structure. The upper and lower end faces of the semi-cylinder 51 are provided with slots 52 matching the connecting rod 4, and the inner surface of the semi-cylinder 51 is provided with a semi-cylindrical groove 53 connected to the inner end of the slot 52, and the diameter of the semi-cylindrical groove 53 is the same as the diameter of the round block.

[0091] Embodiment 2

[0092] A method for accurately measuring the cross-sectional air volume of an underground tunnel, using an accurate cross-sectional air volume measurement device for an underground tunnel as in the first embodiment, specifically comprises the following steps:

[0093] Step 1: Install the device. Hang the slide rail assembly 1 on the top plate of the tunnel, install the moving assembly 2 on the slide rail assembly 1, make the moving gear 23 mesh with the arc-shaped rack 12, insert the slide rod 243 into the guide slot 13, and then install a set of measuring assemblies 3 under the moving assembly 2;

[0094] Step 2, measurement process, running the moving motor 22, driving the moving component 2 and the measuring component 3 to move from one end of the slide rail component 1 to the other end, and running the electric push rod 27 to drive the measuring component 3 to move in the vertical direction, so that the measuring component 3 measures the wind speed data of the same horizontal plane;

[0095] During the movement of the mobile component 2, the mobile component 2 stops when it is at the leftmost position, the middle position and the rightmost position. At this time, the laser scanning module 31 performs a 360° rotation scan on the tunnel, and the cross-sectional data obtained at the leftmost position, the middle position and the rightmost position are recorded as A1, A2 and A3 respectively. At the same time, the wind speed detection module 32 detects the wind speed in the tunnel in real time, and the wind speed data obtained at the leftmost position, the middle position and the rightmost position are v1, v2 and v3 respectively, and all the data are transmitted to the host for calculation and analysis;

[0096] Step 3: Calculate the average wind speed on the cross section based on the wind speed data at each point. Use the weighted average method to average the wind speed data measured by the wind speed detection module 32 according to the weighted position. The formula for the weighted average wind speed is:

[0097] ;

[0098] in, is the weighted mean wind speed, v i is the wind speed measured by the wind speed detection module 32;

[0099] Step 4: Obtain point cloud coordinates. Assume that the laser scanning module 31 scans and generates n points of the tunnel cross-section contour, represented by (x1, y1), (x2, y2), ..., (x n ,y n ), these points are connected in sequence to form a closed polygon;

[0100] Step 5, the first calculation method of the closed polygon uses the polygon area formula. For irregular closed polygons, the calculation formula for the cross-sectional area S1 in Algorithm 1 is:

[0101] ;

[0102] Among them, (x i ,y i ) and (x i+1 ,y i+1 ) represents the coordinates of two adjacent points, and N is the number of sides of the closed polygon;

[0103] Step 6, the second calculation method of the closed polygon uses the integral method to triangulate the closed polygon to obtain multiple small triangles. The area of ​​each small triangle is calculated and summed to obtain the total area of ​​the cross section. The calculation formula of the cross-sectional area S2 of Algorithm 2 is:

[0104] ;

[0105] Among them, S k is the area of ​​the kth small triangle, and m is the number of small triangles obtained by dissection;

[0106] For more complex shapes, use point clouds to build a network or triangulation, and then calculate the sum of the areas of each small triangle. If the angle between two adjacent faces is between 0 and 150 degrees, it can be judged as a more complex shape.

[0107] Step 7, coupling the two tunnel cross-sectional area algorithms of step 5 and step 6 to obtain the accurate cross-sectional area S3 of the tunnel section;

[0108] The cross-sectional areas obtained by the two algorithms are weighted and averaged to make the cross-sectional area more accurate;

[0109] Step 8: Calculate the preliminary cross-sectional air volume. According to the weighted average wind speed and the precise cross-sectional area S3, the calculation formula for the preliminary cross-sectional air volume Q1 is:

[0110] ;

[0111] Step 9: Friction loss of tunnel air volume, including the effect of average roughness on airflow, local flow loss and further effect of irregular cross-section on airflow;

[0112] The friction loss formula is as follows:

[0113] ;

[0114] Where ΔP is the pressure loss, f is the overall friction coefficient, L is the tunnel length, D is the tunnel diameter, ρ is the gas density, and v c is the gas flow velocity;

[0115] In the calculation process, the traditional friction loss calculation formula can provide basic roughness effects, but for irregular shapes and complex cross-section tunnels, relying solely on this formula often cannot accurately reflect the actual flow characteristics;

[0116] The above formula can calculate the pressure loss caused by friction of airflow in the tunnel, but it assumes that the tunnel has a regular circular cross-section and the wall roughness is uniform, which is often not true in actual mines, and the above formula needs to be further corrected and adjusted;

[0117] For roadways, the wall roughness It directly affects the overall friction coefficient f, which is expressed by the following implicit equation:

[0118] ;

[0119] ;

[0120] in, is the wall roughness, Re is the Reynolds number of the airflow, which represents the ratio of the inertia to the viscosity of the airflow, and u is the dynamic viscosity of the gas. This formula can accurately reflect the relationship between the wall roughness and the fluid flow state. However, due to its implicit nature, solving this equation usually requires numerical iteration. Especially in complex tunnel shapes, iterative calculations will be more complicated and time-consuming.

[0121] The tunnel is not a smooth surface. Because it is a rock tunnel, there will be uneven locations on the cross section. Therefore, the inner surface of the tunnel is a complex shape. When performing accurate wind measurement, the accurate tunnel shape needs to be considered.

[0122] In order to further improve the accuracy of calculation, for irregular cross-section tunnels, we need to calculate not only the overall friction loss, but also the local flow loss. The local flow loss is usually caused by factors such as the curvature, angle change, and mutation section of the tunnel. Therefore, it is necessary to introduce the local flow resistance coefficient K to correct these factors. The calculation formula of the local flow resistance is:

[0123] ;

[0124] Where ΔP local is the local flow resistance, K is the local flow resistance coefficient, which usually depends on the shape of the roadway and the flow characteristics of the airflow;

[0125] By considering these local losses, we can obtain more accurate results for airflow distribution and pressure loss calculations. For complex mine tunnels, the local flow resistance coefficient K usually needs to be determined through experimental data or simulation results based on the specific structural characteristics of the tunnel;

[0126] In addition, the airflow in the mine tunnel is often in a turbulent state. In the turbulent state, the airflow is more complex and unstable. At this time, the friction coefficient and flow resistance in the tunnel are no longer a simple linear relationship;

[0127] In order to deal with the above complex situation, CFD simulation technology was introduced. CFD is computational fluid dynamics. By establishing a three-dimensional grid, the flow path, velocity field, pressure field and interaction between the airflow and the wall of the roadway are accurately calculated. The CFD model can capture the slight changes in the airflow in the roadway in detail, and consider multiple factors such as the complex shape of the roadway, wall roughness and flow state, so as to provide more accurate calculation results for the air volume and pressure loss of the roadway, and obtain the following formula:

[0128] ;

[0129] Where ΔP total is the overall flow resistance of the tunnel, f is the overall friction coefficient, and f localis the local friction coefficient, K i is the flow resistance coefficient at a local location in the tunnel, L j is the length of the roadway at the irregular section location, D j is the tunnel diameter at the irregular section location, v j is the gas flow velocity at the irregular section position, i is the local position in the tunnel, j is the local position of the irregular section, the first term considers the effect of average roughness on the airflow, the second term is the local flow loss, and the third term considers the further effect of the irregular section on the airflow, which can provide an accurate and scientific calculation framework for the airflow calculation of irregular tunnels;

[0130] Step 10, calculate the cross-sectional air volume. Combining steps 8 and 9, the precise cross-sectional air volume Q is calculated as:

[0131] .

[0132] Embodiment 3

[0133] The difference from the second embodiment is that:

[0134] like Figure 7 As shown, in step 1, multiple groups of measuring components 3 are installed below the moving component 2.

[0135] Therefore, when conducting measurements, tunnel section scanning and wind speed measurements at different heights can be performed simultaneously to achieve multi-point measurement. In the subsequent data analysis and calculation process, measurement data with large errors can be effectively eliminated, and data with small errors can be fitted and valued, which can effectively improve the accuracy of the data.

[0136] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the present invention. As long as these changes do not deviate from the concept of the present invention, they all belong to the protection scope of the present invention.

Claims

1. An accurate measurement device for air volume in a mine tunnel section, characterized by: It includes a slide rail assembly, a moving assembly, a measuring assembly, a connecting rod and a connecting piece, wherein the moving assembly is movably assembled on the slide rail assembly, the measuring assembly is assembled on the lower end of the moving assembly, the moving assembly and the measuring assembly, and the measuring assemblies are connected through the connecting rod and the connecting piece, and the connecting rod is rotatably assembled on the connecting piece; The slide rail assembly includes a mounting plate and an arc-shaped rack, the arc-shaped rack is fixedly mounted on the lower surface of the mounting plate, and the front and rear surfaces of the arc-shaped rack are both provided with guide grooves; The moving assembly includes a moving box body, a moving gear and a limiting assembly, wherein the moving gear is rotatably assembled in the moving box body, and the moving gear is meshed with an arc-shaped rack, and two limiting assemblies are symmetrically rotatably assembled on the front and rear surfaces of the inner cavity of the moving box body, and the inner ends of the limiting assemblies are inserted into the guide slide grooves; The measuring component is equipped with a laser scanning module and a wind speed detection module; A method for accurately measuring the cross-sectional air volume of an underground tunnel, using the above-mentioned accurate cross-sectional air volume measurement device for an underground tunnel, specifically comprises the following steps: Step 1: Install the device. Hang the slide rail assembly on the top plate of the tunnel, install the moving assembly on the slide rail assembly, mesh the moving gear with the arc rack, insert the slide bar into the guide slot, and then install a set of measuring components under the moving assembly. Step 2, during the measurement process, the moving motor is operated to drive the moving component and the measuring component to move from one end of the slide rail component to the other end, and at the same time, the electric push rod is operated to drive the measuring component to move in the vertical direction, so that the measuring component measures the wind speed data on the same horizontal plane; During the movement of the mobile component, the mobile component stops when it is at the leftmost position, the middle position, and the rightmost position. At this time, the laser scanning module performs a 360° rotation scan on the tunnel, and the cross-sectional data obtained at the leftmost position, the middle position, and the rightmost position are recorded as A1, A2, and A3, respectively. At the same time, the wind speed detection module detects the wind speed in the tunnel in real time, and the wind speed data obtained at the leftmost position, the middle position, and the rightmost position are v1, v2, and v3, respectively, and all the data are transmitted to the host for calculation and analysis; Step 3: Calculate the average wind speed on the cross section based on the wind speed data at each point. Use the weighted average method to average the wind speed data measured by the wind speed detection module according to the weighted position. The formula for the weighted average wind speed is: ； in, is the weighted mean wind speed, v i is the wind speed measured by the wind speed detection module; Step 4: Obtain the point cloud coordinates. Assume that the laser scanning module generates n points of the tunnel cross-section contour by scanning, represented as (x1, y1), (x2, y2), ..., (x n ,y n ), these points are connected in sequence to form a closed polygon; Step 5, the first calculation method of the closed polygon uses the polygon area formula. For irregular closed polygons, the calculation formula for the cross-sectional area S1 in Algorithm 1 is: ； Among them, (x i ,y i ) and (x i+1 ,y i+1 ) represents the coordinates of two adjacent points, and N is the number of sides of the closed polygon; Step 6, the second calculation method of the closed polygon uses the integral method to triangulate the closed polygon to obtain multiple small triangles. The area of ​​each small triangle is calculated and summed to obtain the total area of ​​the cross section. The calculation formula of the cross-sectional area S2 of Algorithm 2 is: ； Among them, S k is the area of ​​the kth small triangle, and m is the number of small triangles obtained by dissection; Step 7, coupling the two tunnel cross-sectional area algorithms of step 5 and step 6 to obtain the accurate cross-sectional area S3 of the tunnel section; Step 8: Calculate the preliminary cross-sectional wind volume based on the weighted average wind speed and precise cross-sectional area S3, the calculation formula for the preliminary cross-sectional air volume Q1 is: ； Step 9: Friction loss of tunnel air volume, including the effect of average roughness on airflow, local flow loss and further effect of irregular cross-section on airflow; The friction loss formula is as follows: ； Where ΔP is the pressure loss, f is the overall friction coefficient, L is the tunnel length, D is the tunnel diameter, ρ is the gas density, and v c is the gas flow velocity; For roadways, the wall roughness Directly affects the overall friction coefficient f, which is expressed by the following implicit equation: ； ； in, is the wall roughness, Re is the Reynolds number of the airflow, which represents the ratio of the inertia to the viscosity of the airflow, and u is the dynamic viscosity of the gas; The local flow resistance coefficient K is introduced for correction, and the calculation formula of the local flow resistance is obtained as follows: ； Where ΔP local is the local flow resistance, K is the local flow resistance coefficient; CFD simulation technology was introduced. CFD is computational fluid dynamics. A three-dimensional grid was established to accurately calculate the flow path, velocity field, pressure field of the airflow in the tunnel and the interaction with the tunnel wall, and the following formula was obtained: ； Where ΔP total is the overall flow resistance of the tunnel, f is the overall friction coefficient, and f local is the local friction coefficient, K i is the flow resistance coefficient at a local location in the tunnel, L j is the length of the roadway at the irregular section location, D j is the tunnel diameter at the irregular section location, v j is the gas flow velocity at the position of the irregular section, i is the local position in the tunnel, and j is the local position of the irregular section; Step 10, calculate the cross-sectional air volume. Combining steps 8 and 9, the precise cross-sectional air volume Q is calculated as: 。 2. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 1, it is characterized by: The limiting assembly includes a rotating shaft, a circular plate, a sliding rod and a limiting ring. The front and rear surfaces of the movable box body are both provided with circular holes, and the rotating shaft is inserted into the circular holes. A circular plate is fixedly installed on the inner end of the rotating shaft, and a sliding rod is fixedly installed on the inner surface side of the circular plate, and the sliding rod is inserted into the guide groove. The two limiting rings are screwed to the outer surface of the rotating shaft, and the two limiting rings are respectively located on the inner and outer sides of the movable box body.

3. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 1, it is characterized by: A moving motor is fixedly mounted on the rear surface of the moving box body, and a moving gear is fixedly mounted on an output shaft of the moving motor. A motor protection shell is mounted on the outer side of the moving motor.

4. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 1, it is characterized by: The left and right surfaces of the moving box body are provided with through slots, and the arc-shaped racks pass through the through slots.

5. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 1, it is characterized by: A fixing plate is fixedly mounted on the lower surface of the moving box body, and an electric push rod is fixedly mounted on the lower surface of the fixing plate in a left-right symmetrical manner.

6. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 5, it is characterized by: Positioning blocks are symmetrically fixedly installed on the left and right surfaces of the measuring component, and threaded holes are provided on the upper surfaces of the positioning blocks.

7. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 6, it is characterized by: A round block is fixedly mounted on one end of the connecting rod and the output end of the electric push rod, and a thread matching the threaded hole is provided on the other end of the connecting rod. The diameter of the connecting rod is the same as the diameter of the output end of the electric push rod.

8. According to the device for accurately measuring the air volume in the cross section of an underground tunnel as described in claim 7, it is characterized by: The connecting piece includes a semi-cylinder, two of which are spliced ​​together to form a cylindrical structure, the upper and lower end faces of the semi-cylinder are provided with slots matching the connecting rod, the inner surfaces of the semi-cylinder are provided with semi-cylindrical grooves connected to the inner ends of the slots, and the diameter of the semi-cylindrical grooves is the same as the diameter of the round block.

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