Effects of air volume ratio parameters on air curtain dust suppression in a rock tunnel's fully-mechanized working face

To investigate the effects of the air volume ratio parameters (axial-to-radial flow ratio of the wall-attached air cylinder delta and the forced-to-exhaust ratio of the ventilation system beta) on the air curtain dust suppression in a rock tunnel's fully-mechanized working face, the eastern belt fully-mechanized working face in Huipodi mining company (Shanxi Mineral Group Co., Ltd., China) was numerically simulated by CFD software in this study. First, a mathematical model for describing the airflow-dust migration in a fully-mechanized working face was established using the Euler-Lagrange method. A full-scale geometrical model of the tunnel was also developed. The effectiveness of the established models and the related parameter settings were then verified by making comparisons between the field measured values and the numerical simulation results. Finally, the airflow migration and dust dispersion rules under different ventilation conditions (delta = 5: 5-1: 9 and beta = 0.5-1.5) were simulated. According to the simulation results, a decrease in delta and beta contributed to the formation of an effective axial dust-suppression air curtain in the fully-mechanized excavating region. For eastern belt fully-mechanized working face and those under similar production conditions, an effective axial dust-suppression air curtain can be formed when delta = 1: 9-2: 8 and beta = 0.5-0.75. When delta = 1: 9 and beta = 0.5-0.75, the high-concentration dust were blocked in the space in front of the driver of heading machine (i.e., within 7 m from the head-on section), which achieved a better dust suppression effect. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.