CFD-based optimization of the installation location of the wall-mounted air duct in a fully mechanized excavation face

Abstract

As a novel ventilation method for fully mechanized excavation face, i.e., wall-mounted air duct, has outstanding advantages in solving the problems of dust pollution and gas overrun. In order to decide the best installation location of the wall-mounted air duct, a physical model was developed proportional to the dimensions of C103 fully mechanized excavation face of the Nahe Coal Mine of the Bai Coal Group in Baise, Guangxi Province. The CFD numerical method was used to analyze the air flow field, dust concentration distribution and gas diffusion of the excavation face when the wall-mounted air duct was installed at different positions. The results showed that the dust and gas control effect in the fully mechanized excavation face was highly dependent on the installation location of the wall-mounted air duct. When the wall-mounted air duct was installed farther away from the working face, on the one hand, the wind curtain moved backward and the dust control effect was poorer; on the other hand, the gas was diffused to a larger distance and the concentration of gas in front of the working face was lower. For the investigated fully mechanized excavation face, the reasonable installation distance of the wall-mounted air duct should be 9.6 m. At this installation distance, the concentration of gas on the working face roof was 0.65%, and the concentration of dusts around the roadheader’s driver was 59 mg/m3.