Analysis of diffusion behavior of harmful emissions from trackless rubber-wheel diesel vehicles in underground coal mines

Abstract

To define the diffusion behavior of harmful exhaust substances from diesel vehicles and support safety risk assessments of underground coal mines, we performed a multi-species coupling calculation of the emission and diffusion of harmful substances from a trackless rubber-wheel diesel vehicle. A computational fluid dynamics (CFD) model of the diffusion of harmful emissions was hence established and verified. From the perspective of risk analysis, the diffusion behavior and distribution of hazardous substances emitted by the diesel vehicle were studied under 4 different conditions; moreover, we identified areas characterized by hazardous levels of emissions. When the vehicle idled upwind in the roadway, high-risk areas formed behind and to the right of the vehicle: particularly high concentrations of pollutants were measured near the rear floor of the vehicle and within 5 m behind the vehicle. When the vehicle idled downwind, high-risk areas formed in front of it: particularly high concentrations of pollutants were measured near the floor and within 5 m from the front of the vehicle. In the above cases, the driver would not breathe highly polluted air and would be relatively safe. When the vehicle idled into the chamber, however, high-risk areas formed on both sides of the vehicle and near the upper roof. Forward entry of the vehicle caused a greater increase in the concentration of pollutants in the chamber and in the driver’s breathing zone compared with reverse entry.