A coal mine underground wind speed and air volume and roadway section integrated laser detection method

Abstract

The application discloses a kind of coal mine underground wind speed and wind volume and roadway section integrated laser detection method, comprising the following steps: step one, install detection device;Step two, construct inclined roadway section;Step three, calculate the area S of inclined roadway section;Step four, calculate the average wind speed V of inclined roadway section avg ;Step five, calculate the wind volume Q, the application designs measuring equipment, built-in laser scanning sensor, can realize 360 ° scanning to roadway, combined with space point cloud reconstruction and section contour identification algorithm, can accurately calculate the real cross-sectional area of different types of roadway, to provide basic data support system for wind volume calculation Wind speed sensor equipped with can be installed in any measuring point position, combined with built-in wind speed field compensation model and section correction coefficient library, the average wind speed under corresponding roadway shape can be calculated from single-point wind speed, significantly improve measurement efficiency and versatility.

Description

Technical Field

[0001] This invention belongs to the field of underground roadway wind speed and air volume detection technology, and specifically provides an integrated laser detection method for underground wind speed and air volume and roadway cross-section in coal mines. Background Technology

[0002] Coal mine ventilation is a crucial aspect of ensuring safe production. Wind speed and air volume, as important parameters of the ventilation system's operation, are essential for preventing gas accumulation, controlling the spread of harmful gases, and improving ventilation efficiency. Currently, most commonly used wind speed and air volume monitoring equipment relies on manual multi-point measurements or fixed multi-sensor deployment, which suffers from cumbersome installation, large measurement errors, and high maintenance costs. This is especially true in inclined roadways, where irregular cross-sections and complex flow field distributions make it difficult for traditional methods to achieve rapid and accurate air volume assessment.

[0003] To address the aforementioned issues, an integrated laser detection device for wind speed, air volume, and cross-sectional identification is proposed, suitable for inclined roadways in underground coal mines. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an integrated laser detection method for underground coal mine wind speed and volume and roadway cross-section.

[0005] To achieve the above objectives, the technical solution adopted by this invention is: an integrated laser detection method for underground coal mine ventilation speed and volume and roadway cross-section, specifically including the following steps:

[0006] Step 1: Install the detection device. Fix the mounting bracket in the inclined roadway and install the measuring equipment on the mounting platform. Adjust the angle of the mounting platform so that the angle of the mounting platform is the same as the inclination angle of the inclined roadway. Construct a coordinate system with the laser scanning head as the origin.

[0007] Step 2: Construct the inclined roadway cross-section, use measuring equipment to measure point cloud information, fit the roadway axis, construct orthogonal tangents on the roadway axis, and form the inclined roadway cross-section;

[0008] Step 3: Calculate the cross-sectional area S of the inclined roadway, project the point cloud onto the orthogonal tangent, identify and remove obstacle points in the point cloud, fit a closed contour on the cross-section of the inclined roadway, and calculate the area.

[0009] Step 4: Calculate the average wind speed V in the inclined tunnel cross-section. avg The wind speed is measured at a single point using a wind speed sensor. Based on the wind speed at the single point, corrections and compensations are made for the location, cross-sectional shape, and disturbance corrections, and the average wind speed is calculated.

[0010] Step 5: Calculate the air volume Q based on the cross-sectional area S of the inclined tunnel and the average wind speed V. avgThe calculated air volume is Q = S × V avg .

[0011] Further, in step one, the detection device includes a measuring device, a mounting bracket, a hydraulic cylinder, and a mounting platform. The mounting bracket is fixedly installed in the inclined roadway, the measuring device is fixedly installed on the mounting platform, a laser scanning head is telescopically mounted on the side of the measuring device, a wind speed sensor is fixedly mounted on the upper surface of the measuring device, and a display screen is mounted on the front surface of the measuring device.

[0012] A base is fixedly installed at the lower end of the mounting bracket, and a deflection side plate is fixedly installed at the upper end of the mounting bracket. A fixed shaft is fixedly installed between the two deflection side plates. A deflection component is fixedly installed on one side of the lower surface of the mounting platform, and the deflection component is rotatably mounted on the fixed shaft. The hydraulic cylinder is fixedly installed on the base, and a support component is fixedly installed at the output end of the hydraulic cylinder. A slide rail is fixedly installed on the other side of the lower surface of the mounting platform, and a slider is movably mounted inside the slide rail. The support component is rotatably mounted on the lower end of the slider.

[0013] Furthermore, step two specifically includes the following steps:

[0014] a. Use PCA technology to fit the tunnel axis and measure n point cloud points p. i =(x i y i , z i Its covariance matrix is:

[0015]

[0016] in:

[0017] It is the vector at point i;

[0018] It is a mean vector;

[0019] b. Construct the tangent equation for a point P on the tunnel axis. i It can be represented as:

[0020]

[0021] in:

[0022] Let P be the point i The cross section at the point;

[0023] s i Scalar coefficients;

[0024] The normal vector of the tangent plane;

[0025] c. Formula for calculating the orthogonal projection point X' from point X to the inner wall of the tunnel:

[0026]

[0027] Where point X = (x, y, z) belongs to the tangent plane. The conditions are:

[0028]

[0029] Furthermore, in step three, the identification and removal of obstacle points in the point cloud, and the fitting of a closed contour on the inclined tunnel cross-section, specifically includes the following steps:

[0030] a. Projecting the point cloud onto a local two-dimensional cross-section: Projecting the collected obstacle 3D point cloud P(x,y,z) onto a tangent perpendicular to the fitted roadway axis:

[0031] P'(u,v)=T(θ,φ)·P;

[0032] in:

[0033] P' is the distance from point P to the tangent plane. orthogonal projection points;

[0034] T(θ,φ) is the transformation matrix from global coordinates to the plane orthogonal to the tunnel axis;

[0035] The point cloud of the local cross-sectional contour is obtained;

[0036] b. Identify obstacle regions and construct a point density function:

[0037]

[0038] in:

[0039] N i This represents the number of points within the neighborhood radius.

[0040] A r The area within the radius of the neighborhood;

[0041] The feature region of the obstacle satisfies the point density ρ m >>ρ avg It has a typical geometric shape, and its outer contour is fitted by RANSAC circle fitting or Hough circle detection:

[0042] (xa) 2 +(yb) 2 =r 2 ;

[0043] The fitting results are used to filter the point cloud and remove obstacle points.

[0044] c. Void interpolation and closure fitting: After the obstacle points are removed, gaps appear in the cross-section of the inclined roadway. Interpolation and polygon fitting are used to close the contour.

[0045] The missing regions are automatically connected into closed contours using the Alpha Shape reconstruction method:

[0046]

[0047] in:

[0048] δ controls the thickness of the reconstructed contour;

[0049] A(δ) represents the region or area associated with the parameter δ;

[0050] E(δ) is the set of edges, representing the edges generated by the parameter δ;

[0051] △(p i ,p j ,p k ) is composed of three points p i p j p k The triangle formed;

[0052] d. Calculate the cross-sectional area after removing obstacles using the polygon formula:

[0053]

[0054] Furthermore, in step d, the cross-sectional area after removing obstacles is calculated using the curve integral area formula, automatically adapting to complex cross-sections and uneven structures:

[0055]

[0056] in:

[0057] C represents the closed curve of the cross-sectional profile after obstacle filtering.

[0058] Furthermore, in step four, corrections and compensations are made for the location, cross-sectional shape, and disturbance correction to obtain the calculated average wind speed V of the cross-section. avg Compensation model:

[0059]

[0060] in:

[0061] V m The actual wind speed was measured at the measuring point;

[0062] α is the position correction coefficient, which corrects the position of the measuring point relative to the center of the cross section;

[0063] β is the cross-sectional shape coefficient, used to correct the influence of cross-sectional type on velocity distribution;

[0064] γ is the disturbance correction coefficient, which corrects local disturbances in ducts, supports, etc.

[0065] Furthermore, the position correction coefficient α, in a circular or approximately elliptical cross-section, results in a wind speed distribution that approximates a parabolic curve along the radial direction:

[0066]

[0067] in:

[0068] V(r) is the point wind speed with radius r;

[0069] V0 is the maximum wind speed at the axis;

[0070] r is the distance from the measuring point to the center;

[0071] R is the equivalent radius of the tunnel;

[0072] n is the flow regime index; for laminar flow, n = 1; for turbulent flow, n ≈ 1 / 7 to 1 / 9.

[0073] For a certain measuring point r m At that location, the position correction factor is obtained as follows:

[0074]

[0075] The position correction coefficient obtained after integration is:

[0076]

[0077] Furthermore, the cross-sectional shape coefficient β has different values ​​for different cross-sectional shapes. If the cross-sectional shape is rectangular, the cross-sectional shape coefficient β is 1.0 to 1.2; if the cross-sectional shape is trapezoidal, the cross-sectional shape coefficient β is 1.1 to 1.3; and if the cross-sectional shape is arched, the cross-sectional shape coefficient β is 1.3 to 1.5.

[0078] Furthermore, the disturbance correction coefficient γ is obtained using CFD simulation:

[0079] γ = 1 + δ;

[0080] in:

[0081] δ is the disturbance coefficient, ranging from 0.05 to 0.3.

[0082] The beneficial effects of using this invention are:

[0083] This invention designs a measuring device with a built-in laser scanning sensor that can perform 360° scanning of the tunnel. Combined with spatial point cloud reconstruction and cross-sectional contour recognition algorithms, it can accurately calculate the real cross-sectional area of ​​different types of tunnels, thereby providing basic data support for air volume calculation.

[0084] Compared with traditional cross-section estimation methods, this invention has higher geometric reconstruction accuracy. Especially when there are obstacles such as air ducts and water pipes, the system can identify and remove interference areas through point cloud intelligent segmentation and shape fitting algorithms, so as to achieve automatic obstacle avoidance and cross-section reconstruction.

[0085] The system is equipped with a wind speed sensor that can be installed at any measuring point. Combined with the built-in wind speed field compensation model and cross-section correction coefficient library, the average wind speed under the corresponding tunnel shape can be calculated from the wind speed at a single point, which significantly improves measurement efficiency and versatility.

[0086] The overall device of the present invention has a compact structure and high integration, and is particularly suitable for complex scenarios with limited underground space, varied roadways, and large airflow disturbances. Attached Figure Description

[0087] Figure 1 This is one of the three-dimensional schematic diagrams of the detection device of the present invention.

[0088] Figure 2 This is a second three-dimensional schematic diagram of the detection device of the present invention.

[0089] Figure 3 This is a schematic diagram of the tunnel axis and inclined tunnel cross-section of the present invention.

[0090] Figure 4 This is a schematic diagram of the installation of the detection device of the present invention.

[0091] The reference numerals in the attached drawings include: 1. Measuring equipment; 11. Laser scanning head; 12. Wind speed sensor; 13. Display screen; 2. Mounting bracket; 21. Deflection side plate; 3. Hydraulic cylinder; 31. Support component; 32. Protective housing; 4. Mounting platform; 41. Deflection component; 42. Slide rail; 43. Slider. Detailed Implementation

[0092] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0093] A laser detection method integrating underground ventilation speed and volume with roadway cross-section in coal mines, specifically including the following steps:

[0094] Step 1: Install the detection device, such as... Figure 4 As shown, a support bracket 2 is fixedly installed in the inclined roadway, and a measuring device 1 is installed on the installation platform 2. The angle of the installation platform 4 is adjusted so that the angle of the installation platform 4 is the same as the inclination angle of the inclined roadway. A coordinate system is constructed with the laser scanning head 11 as the origin.

[0095] like Figure 1 and Figure 2 As shown, the detection device includes a measuring device 1, a mounting bracket 2, a hydraulic cylinder 3, and a mounting platform 4. The mounting bracket 2 is fixedly installed in the inclined roadway, the measuring device 1 is fixedly installed on the mounting platform 4, a laser scanning head 11 is telescopically mounted on the side of the measuring device 1, a wind speed sensor 12 is fixedly mounted on the upper surface of the measuring device 1, and a display screen 13 is mounted on the front surface of the measuring device 1.

[0096] A base is fixedly installed at the lower end of the mounting bracket 2, and a deflection side plate 21 is fixedly installed at the upper end of the mounting bracket 2. A fixed shaft is fixedly installed between the two deflection side plates 21. A deflection component 41 is fixedly installed on one side of the lower surface of the mounting platform 4, and the deflection component 41 is rotatably mounted on the fixed shaft. A hydraulic cylinder 3 is fixedly installed on the base, and a support component 31 is fixedly installed at the output end of the hydraulic cylinder 3. A slide rail 42 is fixedly installed on the other side of the lower surface of the mounting platform 4. A slider 43 is movably mounted inside the slide rail 42, and the support component 31 is rotatably mounted on the lower end of the slider 43.

[0097] Mounting bracket 2 is installed in the inclined roadway via a base, and then the measuring device 1 is installed and supported on the mounting platform 4. An inclination sensor is installed inside the mounting bracket 2 to measure the inclination angle when the mounting bracket 2 is installed in the inclined roadway. The mounting bracket 2 also contains a processor and an oil tank. After receiving the inclination angle signal, the processor controls the hydraulic pump on the oil tank, and then controls the operation of the hydraulic cylinder 3 to adjust the angle of the mounting platform 4, thereby adjusting the angle of the measuring device 1 and the laser scanning head 11, so that the laser scanning head 11 can scan the end face of the roadway more smoothly.

[0098] The laser scanning head 11 is retractable and can be controlled by the built-in program of the measuring device 1 or by remote operation. Before measuring point cloud information, the laser scanning head 11 needs to be extended to the outside of the mounting platform 4 so that point cloud information can be accurately obtained and the roadway axis can be accurately fitted to obtain the inclined roadway cross section.

[0099] The wind speed sensor 12 is used to measure the wind speed information at its location.

[0100] The tunnel contour, cross-sectional area, wind speed information obtained by the laser scanning head 11 and the wind speed sensor 12, as well as the calculated air volume information, can all be displayed on the display screen 13.

[0101] In addition, regarding the installation location of the mounting bracket 2, it can also be set on the top surface of the roadway, depending on the actual conditions inside the roadway.

[0102] Step 2: Construct the inclined roadway cross-section. Use measuring device 1 to measure point cloud information, fit the roadway axis, and construct orthogonal tangents on the roadway axis to form the inclined roadway cross-section. This includes the following steps:

[0103] a. Use PCA technology to fit the tunnel axis and measure n point cloud points p. i =(x i y i , z i Its covariance matrix is:

[0104]

[0105] in:

[0106] It is the vector at point i;

[0107] It is a mean vector;

[0108] T is the transpose symbol. For transpose;

[0109] The tunnel axis can be found using the above formula;

[0110] b. Construct the tangent equation for a point P on the tunnel axis. i It can be represented as:

[0111]

[0112] in:

[0113] Let P be the point i The cross section at the point, the cross section That is, the plane in which the inclined tunnel cross-section is located;

[0114] The origin is the coordinate vector of the starting point, i.e., the reference origin. In this embodiment, it is the location of the laser scanning head 11.

[0115] s i The scalar coefficient represents the value from... Along direction The "distance" scale of movement;

[0116] The normal vector of the tangent plane;

[0117] c. Formula for calculating the orthogonal projection point X' from point X to the inner wall of the tunnel:

[0118]

[0119] Where point X = (x, y, z) belongs to the tangent plane. The conditions are:

[0120]

[0121] Multiple orthogonal projection points X' form the cross-sectional profile, thus obtaining the inclined roadway cross-section.

[0122] like Figure 3 As shown in the figure, the solid line part is a schematic diagram of the inclined roadway, the dashed straight line represents the roadway axis, and the circular dashed line represents the cross-sectional outline, thus obtaining the cross-section of the inclined roadway.

[0123] Step 3: Calculate the cross-sectional area S of the inclined roadway, project the point cloud onto the orthogonal tangent plane, identify and remove obstacle points in the point cloud, fit a closed contour on the inclined roadway cross-section, and calculate the area, including the following steps:

[0124] The original point cloud contains information about the tunnel structure and obstacles, including air ducts, water pipes, and cables. During cross-section recognition, the obstacle point cloud needs to be removed, retaining only the tunnel wall outline. This portion can be used as a preprocessing step in the LiDAR cross-section extraction algorithm to improve cross-section recognition accuracy.

[0125] a. Projecting the point cloud onto a local two-dimensional cross-section: Projecting the collected obstacle 3D point cloud P(x,y,z) onto a tangent perpendicular to the fitted roadway axis:

[0126] P'(u,v)=T(θ,φ)·P;

[0127] in:

[0128] P' is the distance from point P to the tangent plane. orthogonal projection points;

[0129] T(θ,φ) is the transformation matrix from global coordinates to the plane orthogonal to the tunnel axis;

[0130] Obtain the point cloud of the local cross-sectional contour of the obstacle;

[0131] b. Identify obstacle regions and construct a point density function:

[0132]

[0133] in:

[0134] N i This represents the number of points within the neighborhood radius.

[0135] A r The area within the radius of the neighborhood;

[0136] The feature region of the obstacle satisfies the point density ρ m >>ρ avg It has a typical geometric shape, and its outer contour is fitted by RANSAC circle fitting or Hough circle detection:

[0137] (xa) 2 +(yb) 2 =r 2 ;

[0138] in:

[0139] ρ m It is the local point density of the m-th point, representing the number of points within a certain neighborhood (such as radius r) centered on the m-th point;

[0140] ρ avg It is the average point density globally or within a region, the average point density of all points or within a specified range, used to compare outliers;

[0141] Point density determination formula ρ i >>ρ avg It is commonly used for obstacle recognition or anomaly detection in point cloud data analysis;

[0142] The fitting results are used to filter the point cloud and remove obstacle points.

[0143] c. Void interpolation and closure fitting: After the obstacle points are removed, gaps appear in the cross-section of the inclined roadway. Interpolation and polygon fitting are used to close the contour.

[0144] The missing regions are automatically connected into closed contours using the Alpha Shape reconstruction method:

[0145]

[0146] in:

[0147] δ controls the thickness of the reconstructed contour;

[0148] A(δ) is the region or area associated with the parameter δ, which can be a region formed in a δ-shape or δ-complex structure;

[0149] E(δ) is the set of edges, representing the edges generated by the parameter δ;

[0150] (p i ,p j ) indicates from point p i Point P j A directed edge;

[0151] (p i ,pj )∈E(δ) represents the edge (p) i ,p j ) belongs to the edge set E(δ);

[0152] △(p i ,p j ,p k ) is composed of three points p i p j p k The triangle formed, where p i p j p k Points in a point set are typically data points in a plane or space.

[0153] This represents the fitting of the remaining useful contour after removing the local cross-sectional contour point cloud of the above obstacles;

[0154] d. Calculate the cross-sectional area after removing obstacles using the polygon formula:

[0155]

[0156] In addition, the cross-sectional area after removing obstacles can be calculated using the curve integral area formula, automatically adapting to complex cross-sections and uneven structures:

[0157]

[0158] in:

[0159] C is the closed curve of the cross-sectional profile after obstacle filtering;

[0160] This formula automatically adapts to complex cross-sections and recessed structures.

[0161] Step 4: Calculate the average wind speed V in the inclined tunnel cross-section. avg The wind speed sensor 12 is used to measure the wind speed at a single point. Based on the wind speed at the single point, corrections and compensations are made for the location, cross-sectional shape, and disturbance correction, and the average wind speed is calculated.

[0162] Since wind speed measuring points are set at arbitrary locations within the roadway (excluding the roadway center or the area of ​​maximum flow velocity), their values ​​cannot directly represent the average wind speed of the cross-section. When calculating the average score from wind speeds at arbitrary locations, the following factors need to be considered:

[0163] 1. The cross-sectional shape of the tunnel, including arched, trapezoidal, rectangular, etc.;

[0164] 2. Velocity distribution, i.e., the difference between the boundary layer and the center;

[0165] 3. Flow state, i.e. laminar or turbulent flow;

[0166] 4. Systematic errors caused by the offset of the measuring point position;

[0167] 5. Asymmetric flow field caused by local disturbances (ducts, supports, etc.);

[0168] To address the above, corrections and compensations are needed for location, cross-sectional shape, and disturbance correction to obtain the calculated average wind speed V across the cross-section. avg Compensation model:

[0169]

[0170] Where: V m The actual wind speed was measured at the measuring point;

[0171] α is the position correction coefficient, which corrects the position of the measuring point relative to the center of the cross section;

[0172] β is the cross-sectional shape coefficient, used to correct the influence of cross-sectional type on velocity distribution;

[0173] γ is the disturbance correction coefficient, which corrects local disturbances in ducts, supports, etc.

[0174] The position correction factor α, in a circular or approximately elliptical cross-section, causes the wind speed to vary approximately parabolically along the radial direction:

[0175]

[0176] in:

[0177] V(r) is the point wind speed with radius r;

[0178] V0 is the maximum wind speed at the axis;

[0179] r is the distance from the measuring point to the center;

[0180] R is the equivalent radius of the tunnel;

[0181] n is the flow regime index; for laminar flow, n = 1; for turbulent flow, n ≈ 1 / 7 to 1 / 9.

[0182] For a certain measuring point r m At that location, the position correction factor is obtained as follows:

[0183]

[0184] r m The radius of a certain point, i.e., the local radius;

[0185] The position correction coefficient obtained after integration is:

[0186]

[0187] As can be seen from the formula, the closer the measuring point is to the edge, the lower the wind speed, and the larger the correction coefficient.

[0188] The cross-sectional shape coefficient β is shown in Table 1. The value varies for different cross-sectional shapes. If the cross-sectional shape is rectangular, the cross-sectional shape coefficient β is 1.0 to 1.2. If the cross-sectional shape is trapezoidal, the cross-sectional shape coefficient β is 1.1 to 1.3. If the cross-sectional shape is arched, the cross-sectional shape coefficient β is 1.3 to 1.5.

[0189] Table 1: Shape Factor Table

[0190] rectangle 1.0～1.2 The velocity distribution is relatively uniform. trapezoid 1.1～1.3 The lower part has a higher speed than the top. arch 1.3～1.5 The wind speed at the center is significantly higher than that at the sides.

[0191] The disturbance correction factor γ is determined by the presence of obstacles (ducts, cable trays, etc.) near the measuring point, which can cause local velocity changes. It is obtained through CFD simulation or practical experience.

[0192] γ = 1 + δ;

[0193] Where: δ is the disturbance coefficient, ranging from 0.05 to 0.3.

[0194] Step 5: Calculate the air volume Q based on the cross-sectional area S of the inclined tunnel and the average wind speed V. avg The calculated air volume is Q = S × V avg .

[0195] The above content is only a preferred embodiment of the present invention. For those skilled in the art, many changes can be made in the specific implementation and application scope based on the concept of the present invention. As long as these changes do not depart from the concept of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A laser detection method integrating underground ventilation speed and volume with roadway cross-section in coal mines, characterized in that, Specifically, the following steps are included: Step 1: Install the detection device. Fix the mounting bracket in the inclined roadway and install the measuring equipment on the mounting platform. Adjust the angle of the mounting platform so that the angle of the mounting platform is the same as the inclination angle of the inclined roadway. Construct a coordinate system with the laser scanning head as the origin. Step 2: Construct the inclined roadway cross-section, use measuring equipment to measure point cloud information, fit the roadway axis, construct orthogonal tangents on the roadway axis, and form the inclined roadway cross-section; Step 3: Calculate the cross-sectional area S of the inclined roadway, project the point cloud onto the orthogonal tangent, identify and remove obstacle points in the point cloud, fit a closed contour on the cross-section of the inclined roadway, and calculate the area. Step 4: Calculate the average wind speed in the inclined tunnel cross-section. The wind speed is measured at a single point using a wind speed sensor. Based on the wind speed at the single point, corrections and compensations are made for the location, cross-sectional shape, and disturbance corrections, and the average wind speed is calculated. Corrections and compensations are made for location, cross-sectional shape, and disturbance correction to obtain the calculated average wind speed V of the cross-section. avg Compensation model: ； in: V m The actual wind speed was measured at the measuring point; This is a position correction coefficient, used to correct the position of the measuring point relative to the center of the cross section. This is the cross-sectional shape factor, used to correct the influence of cross-sectional type on velocity distribution; This is the disturbance correction factor, used to correct local disturbances in ducts and supports; The position correction coefficient In a circular or approximately elliptical cross-section, the wind speed varies approximately as a parabola along the radial direction: ； in: For Point wind speed with radius; Maximum wind speed at the axis; The distance from the measuring point to the center; The equivalent radius of the tunnel; The flow regime index indicates laminar flow. turbulence ; For a certain measuring point r m At that location, the position correction factor is obtained as follows: ； The position correction coefficient obtained after integration is: ； The cross-sectional shape coefficient The value varies depending on the cross-sectional shape. For example, if the cross-sectional shape is rectangular, the cross-sectional shape coefficient is... The value is 1.0 to 1.

2. If the cross-sectional shape is trapezoidal, the cross-sectional shape factor is... The value is 1.1 to 1.

3. If the cross-sectional shape is arched, the cross-sectional shape factor is... It is 1.3 to 1.5; The disturbance correction coefficient The results were obtained using CFD simulation: ； in: The disturbance coefficient ranges from 0.05 to 0.

3. Step 5: Calculate the air volume Q based on the cross-sectional area S of the inclined tunnel and the average wind speed. The calculated air volume is .

2. The integrated laser detection method for underground ventilation speed and volume and roadway cross-section in coal mines according to claim 1, characterized in that: In step one, the detection device includes a measuring device, a mounting bracket, a hydraulic cylinder, and a mounting platform. The mounting bracket is fixedly installed in the inclined roadway, the measuring device is fixedly installed on the mounting platform, a laser scanning head is telescopically mounted on the side of the measuring device, a wind speed sensor is fixedly mounted on the upper surface of the measuring device, and a display screen is mounted on the front surface of the measuring device. A base is fixedly installed at the lower end of the mounting bracket, and a deflection side plate is fixedly installed at the upper end of the mounting bracket. A fixed shaft is fixedly installed between the two deflection side plates. A deflection component is fixedly installed on one side of the lower surface of the mounting platform, and the deflection component is rotatably mounted on the fixed shaft. The hydraulic cylinder is fixedly installed on the base, and a support component is fixedly installed at the output end of the hydraulic cylinder. A slide rail is fixedly installed on the other side of the lower surface of the mounting platform, and a slider is movably mounted inside the slide rail. The support component is rotatably mounted on the lower end of the slider.

3. The integrated laser detection method for underground ventilation speed and volume and roadway cross-section in coal mines according to claim 1, characterized in that: Step two specifically includes the following steps: a. Use PCA technology to fit the tunnel axis and measure n point cloud points p. i = (x i y i , z i Its covariance matrix is: ； in: It is the vector at point i; It is a mean vector; b. Construct the tangent equation for a point P on the tunnel axis. i It can be represented as: ； in: Let P be the point i The cross section at the point; Scalar coefficients; The normal vector of the tangent plane; c. Formula for calculating the orthogonal projection point X' from point X to the inner wall of the tunnel: ； Where point X = (x, y, z) belongs to the tangent plane. The conditions are: 。 4. The integrated laser detection method for underground ventilation speed and volume and roadway cross-section in coal mines according to claim 1, characterized in that: In step three, the process of identifying and removing obstacle points from the point cloud and fitting a closed profile on the inclined tunnel cross-section specifically includes the following steps: a. Projecting the point cloud onto a local two-dimensional cross-section: Projecting the collected obstacle 3D point cloud P(x,y,z) onto a tangent perpendicular to the fitted roadway axis: ； in: From point P to the tangent plane orthogonal projection points; This is the transformation matrix for rotating from global coordinates to a plane orthogonal to the tunnel axis; The point cloud of the local cross-sectional contour is obtained; b. Identify obstacle regions and construct a point density function: ； in: N i This represents the number of points within the neighborhood radius. A r The area within the radius of the neighborhood; Obstacle feature regions satisfy point density 》 It has a typical geometric shape, and its outer contour is fitted by RANSAC circle fitting or Hough circle detection: ； The fitting results are used to filter the point cloud and remove obstacle points. c. Void interpolation and closure fitting: After the obstacle points are removed, gaps appear in the cross-section of the inclined roadway. Interpolation and polygon fitting are used to close the contour. The missing regions are automatically connected into closed contours using the Alpha Shape reconstruction method: ； in: To control the thickness of the reconstructed contour; For parameters The associated region or area; Let be the set of edges, representing the parameters. The generated edges; For three points , , The triangle formed; d. Calculate the cross-sectional area after removing obstacles using the polygon formula: 。 5. The integrated laser detection method for underground ventilation speed and volume and roadway cross-section in coal mines according to claim 4, characterized in that: In step d, the cross-sectional area after removing obstacles is calculated using the curve integral area formula, automatically adapting to complex cross-sections and uneven structures: ； in: C represents the closed curve of the cross-sectional profile after obstacle filtering.

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