Applying the similarity theory to model dust dispersion during coal-mine tunneling

Abstract

With the improvement of coal mine driving mechanization, the mining efficiency has been greatly improved. However, the problem of coal dust pollution becomes more serious. In order to improve the environment and dust removal efficiency of tunneling face, it is necessary to master the law of dust migration under the condition of dynamic coal cutting in fully mechanized tunneling face. Therefore, based on the similarity theory and the theory of gas-solid two-phase flow, the numerical simulation and similarity experiments are used to study the distribution of dust concentration and the dust diffusion characteristics in fully mechanized tunneling face with variable dust sources under the condition of forced ventilation. The results show that because of the difference of air velocity in the attachment area of impinging jet, the initial velocity and direction of the dust released from different dust sources are obviously different. The dust from the upper sources moves upward under the influence of the initial airflow, which causes high concentration of the roadway. While the dust from the lower sources moves downwards with the airflow, which hinders the dust flying to a certain extent. The dust diffusion range and concentration are significantly reduced in the case of lower dust source, and most of the dust moves along the bottom of the roadway or stays on the roadway floor. In addition, the similar experimental results of air velocity and dust concentration correspond well to the simulation results, which verifies the reliability of the simulation. These results are expected to provide a basis for the reasonable arrangement of dust prevention measures in fully mechanized tunneling face and improve the working face environment more effectively.