Investigation on flow field characteristics in an open-pit coal mine.

In this paper, the atmospheric flow field characteristics in a deep open-pit mine are investigated numerically and theoretically. A theoretical model on the recirculation length based on the energy equation is used, and a total variation diminishing (TVD) difference scheme with second-order accuracy is used to solve the NS equations with a standard two-equation k-ε turbulence model. The effects of elevated inner dump on the flow field characteristics of the open-pit mine are analyzed detailedly with the same inflow parameters. The results show that a recirculation zone exists in the open-pit mine due to the reflux from the high-pressure zone to the low-pressure zone. As the height of the inner dump increases, the flow becomes more complicated, and the low-pressure zone and the recirculation zone become bigger. The elevated inner dump makes it difficult for the internal fluid to flow to the outside, which results in the increase of the dust concentration. At last, the influences of key parameters on flow filed are conducted by normalizing the depth of the lowest direct current flow on the windward slope. The sensitivity analysis is done by study each influencing factor. This paper offers an effective way to study the flow field characteristics in an open-pit coal mine, which is essential to the dust pollution control of open-pit mine.