Numerical Simulation Of CT 3D Reconstruction Of Gas Seepage In Artificial Fractured Coal Based On Interpolation Algorithm

The formation and storage of coal mine gas in the pore structure of coal and rock,its flow channel is mainly the fracture structure in the coal seam,and the complex fracture structure in the coal body greatly affects and even controls the seepage characteristics.Because of the coal seam gas mining,gas disaster prevention and control and other engineering problems related to the seepage of coal fracture,the study of the influence of the structural characteristics of the fractures on the seepage is of great guiding significance for the scientific development and utilization of coal bed gas and gas disaster prevention and control.In order to obtain the real physical model containing artificial fractures of coal,and by exploring the internal gas seepage law of numerical simulation,CT scanning experiment,3D reconstruction technology,based on the finite element analysis method,proposed by the coal body reconstruction model into the finite element model of the coal train of thought of this research,gradually carry out the research on this the simulation of CT 3D reconstruction of artificial fractures of coal gas seepage based on interpolation algorithm.The high precision CT system CT225kVFCB a CT scan on coal sample collection,the CT image of the coal sample.Through the noise recognition method,it is found that the Gauss noise exists in the existing CT images.The Wiener filter is applied to denoise,and the CT image after denoising is obtained.Then the CT image after de-noising is used as the input sample,and the 3D reconstruction of the coal body CT image based on interpolation reconstruction can improve the data accuracy in the reconstruction process and lay a good data base for the next step of the research.The size of the pixel in the CT image reflects the change of the interior density of the object.When the maximum gray value is white,the density of the object is the largest,representing the skeleton of the coal rock mass;the gray value is black at the most hourly,the density of the object is the smallest,which represents the pore fissure.In this paper,we use the feature of CT picture to make the smallest gray value square,regular pentagon,regular hexagon,circle and ellipse in CT image to represent different kinds of fractured surfaces.The artificial fissures of different angles are realized by changing the plane of artificial fractures and changing the different moving distances of each picture.After processing the CT images containing square,regular pentagon,regular hexagon,circular and elliptical fissures,the DTM threshold segmentation method is adopted,and the real mathematical model of coal fracture is obtained based on 3D reconstruction.According to the real property of coal body,the reasonable boundary conditions are established,and then the finite element model based on the real coal structure is obtained.A finite element numerical simulation experiment is carried out by establishing the finite element model of artificial fractureed coal.In the simulation,the most basic unsteady Navier-Stokes equation is used as the control equation.The model is solved iteratively,and the CFX software is used to simulate the gas seepage flow in the artificial fractured coal.It is found that the seepage velocity of the fractured coal body is larger than that of the original coal,which indicates that the existence of the fissure will increase the gas seepage velocity in the coal body.When the fracture space shape is the same,the seepage velocity of coal section has no obvious rule with the change of angle,which may be influenced by other pore fissure structure.In order to further analyze the seepage law of gas in the fissure in the coal body and to extract the penetration rate of the artificial fracture section in the coal body,it is found that under the same shape,the penetration rate of the fracture section increases with the increase of the fracture angle,and the penetration velocity of the fracture surface with the same angle and different shape is found to increase with the increase of the number of fractures(square to round)with the increase of the number of fractures.