Multi-Field Coupling Model And Simulation Of Dual Dust Sources In Fully Mechanized Mining Face

Dust movement in fully mechanized mining face is a process of multi-dust source,multi-field and multi-factor interaction.There is little research on dust migration under gas-solid-liquid coupling in the existing theory.In order to further study this theory and visualize the theoretical dynamic simulation,this paper takes the respirable dust of dual dust sources(shifting frame and cutting coal)in the environment of airflow field,dust field and fog droplet field in fully mechanized mining face as the research object.The coupling model is established,the similar experiments are carried out,the coefficients are determined,the models are verified,and the simulation is carried out by programming.Finally,the system software is developed.Theoretical results and dynamic simulation can provide decision support for the improvement of the spray and dust control facilities.Based on the theory of gas-solid two phase flow,a three-dimensional mathematical model of respirable dust diffusion under a gas-solid coupling is established in the specific environment of fully mechanized coal mining face.Combined with the theory of spray and dust suppression,a spray dustfall model based on the mixed Gauss model is put forward,and three-dimensional mathematical model of the respirable dust dispersion under gas-solid-liquid coupling is established.In order to obtain the data of coupling model coefficients,the similarity theory was used to build the experimental model of fully mechanized coal mining face,and the air-water spray dust suppression system was determined.The location of the experimental points was selected,and the wind speed distribution and the distribution law of respirable dust concentration of the coal cutter,transportation road and sidewalk under different gas-solid-liquid coupling were analyzed.The influence of airflow field on dust field is obvious.Under the same dust source and spray condition,respirable dust concentration distribution at different positions and heights is different.Under different dust sources and spray conditions,the distribution of respirable dust concentration at the same height is also different,indicating that grasping the concentration distribution of respirable dust in the whole working face is crucial for effective dust suppression..The experimental data are divided into training set and test set.The maximum likelihood method and gradient descent method are used to solve the gas solid coupling turbulent diffusion coefficient.Linear regression method and gradient descent method are used to solve the gas solid coupling coefficient of dual dust sources.The least square method and gradient descent method are used to solve the coefficient of gas solid liquid coupling spray dust suppression model.In order to determine the better coupling model coefficients and optimize the accuracy of the coupling model,Lagrange interpolation method was used to enhance the training set data with different multiples,and the average relative error was used to evaluate the test set data and theoretical values.The results show that the gas-solid coupling of single-mover dust source is 18.99%,the gas-solid coupling of single-cut coal dust source is 22.1%,the gas-solid coupling of double-dust source is 25.73%,the gas-solid-liquid coupling of single-mover dust source is 24.63%,the gas-solid-liquid coupling of single-cut coal dust source is 26.02%,and the gas-solid-liquid coupling of double-dust source is 30.64%,which verifies the reliability of the coupling model.According to the established dual-dust source multi-field coupling model,the simulation software is compiled by using MATLAB and the system design is carried out.Taking the coal cutter,transport and sidewalk as the research object,the spatial and temporal distribution of respiratory dust concentration is simulated from different perspectives,such as 3D stereogram,2D section plane map and isoline map of section concentration.The simulation system can more intuitively and conveniently determine the concentration of respirable dust under different conditions,and provide more effective theoretical basis for dust control and dust reduction.