基于LBM的集中涌出瓦斯在通风网络中蔓延仿真

Simulation of concentrative emission gas spreading in ventilation networks based on LBM

应用速度-浓度双分布格子 Boltzmann模型建立了基于LBM的瓦斯蔓延速度模型和浓度模型,并通过Boussinesq方程将2个模型有机耦合起来。采用基于分块耦合算法的速度-浓度LBM模型将巷道分成若干规则的块,对各块分别独立计算,仅在边界处交换数据,从而去除冗余网格,简化了网格计算,提高了系统资源利用效率。模拟实例结果表明,通过该模型可得到集中涌出瓦斯在通风网络中蔓延的直观信息和其速度、体积分数、压力等大量数据,还可以得到每条巷道内瓦斯体积分数峰值及其个数、位置和到达时间,从而能提供有效避开高浓度瓦斯的方案。集中涌出瓦斯在通风网络中蔓延一段时间后总体体积分数会降低,但是由于某些位置(如巷道拐角、巷道风流交汇处)的风流处于紊流状态,其瓦斯体积分数相对比较高,人员进入矿井时应尽量避免在这些地方停留。

The main purpose of this paper is to introduce an approach to the simulation of coal-mining concentrative emission gas spreading in ventilation networks based on the Lattice Boltzmann Method （LBM）. As is known, concentrative emission of high-pressure gas in underground mining often results in mining pit explosion. Therefore, it is of great emergency to explore the regularities of the gas spreading occurrences in the ventilation networks so as to make a better control and prevent from any gas-explosion disasters in the underground conditions. It is just from this imperative need that we have developed a simulation model of concentrative emission gas spreading in the above-said situations, in which a double distributed velocity-concentration LBM is adopted. In order to simulate the complicated situations, tunnels are separated into some relative regular blocks through the block coupling algorithms. In the model, each block is calculated in parallel, with the data exchanged only on boundaries. As a result, the redundant grids are removed and the grid computation has been simplified with the system resource efficiency ameliorated. While constructing the gas spreading velocity and the gas concentration formulation, we have coupled the two sides organically by using Boussinesq equation. The simulation results show that the so-called LBM model is in a position to obtain essential data and information on the velocity, pressure and visual information about the gas in the tunnels. The simulation results also help to disclose the regularities on the distribution of gas bulk fraction in the tunnels, and those on the speed, pressure and bulk fraction of the gas in different points and places in the tunnels, which are of great benefit for mine safety control and management. Advice and suggestions have also been made that miners and technicians should not stay in the comers and concourses of two or more tunnels where air and gas exchanges are done in a turbulent manner at concentrations higher and thicker so as to avoid the concentrative emission gas spreading.