Study On The Dust Migration In Fully Mechanized Winning Face With Far-pressing-near-absorption Ventilation

Dust is one of five natural disasters in coal mine. Almost every production sites will generate dust particles in the process of coal mining. Because of the complexity of excavation process in fully mechanized winning face.It is easy to generate a large amount of dust particles in the process of mining and leading to the dust pollution problem is prominent.With the constant improvement of the coal mine tunneling technology in recent years, the massive increase in coal mining intensity and production concentration, so as to create favorable conditions for the large-scale, intensive production of the coal industry. A large number of dust particles are scattered under the action of wind and the dust particles threat to the health of human body, especially the respirable dust particles of the most harmful to human body. Long-term inhalation of dust particles that human suffering from pneumoconiosis, at the same time a large number of dust particles in certain conditions will explode, can cause a large number of casualties and property losses, this will seriously threat to the mine safety production.Dust particles also wear of mechanical equipment, reduce the service life and at the same time increase the maintenance cost of the equipment. So in this paper, the movement of dust particles are analyzed in theory and numerical simulation of flow field and dust particles distribution in fully mechanized winning face with far-pressing-near-absorption ventilation by means of the numerical software and provide theoretical support to take effective dust control measures in fully mechanized winning face. There is a great significance for the protection of mine safety and staff’s safety.This paper discusses the influence factors of dust generated in fully mechanized winning face include natural conditions and production conditions. Natural conditions include: geological structure, coal and rock’s physical property and other factors. The main production conditions: production intensity, ventilation, mining methods and cutting parameters and other factors. According to the mathematical model for the motion of dust particles in the wind, dust particles in the still air, dust particles in the roadway subsidence and diffusion and the collision between dust particles motion are analyzed. In addition to reduce dust concentration better in the fully mechanized winning face, this paper is based on the gas-solid two-phase flow, established a three-dimensional model of tunneling through the numerical software GAMBIT and using the FLUENT software to simulate the flow field distribution and the variation of dust concentration. According to the distribution of dust to the following conclusion:(1)the distance of working face about 10 meters position,the dust concentrations generally reached the highest value, dust concentration decreases with distance and finally tends to be stable;(2)The effect of wind speed in tunnel on dust concentration is relatively large, changing wind speed can reduce the concentration of dust;(3)The results of numerical simulation results are quite similar with the field measurement, which can certify the adaptability of models and optional method. Through numerical simulation results are reasonable and credible to guide mine dust prevention has very important reference value.