Dust control mechanism of double radial swirl shielding ventilation in fully mechanized heading face

The double radial swirl shield ventilation is a new type of ventilation and dust control method in fully mechanized heading face. In order to obtain the dust control mechanism of this new ventilation method, a numerical simulation model of double radial swirl shielding ventilation for a fully mechanized heading face was established based on a fully mechanized heading face at a coal mine of Guangxi Baise Coal Group. Based on the Fluent software, the Realizable k-ε turbulence model and the DPM (discrete phase model) are combined to simulate the wind flow field and dust concentration distribution of the fully mechanized heading face under this ventilation method. The results show that the double radial swirl shield ventilation can form two rotating air curtains in the fully mechanized heading face, namely the No.1 air curtain in front of the roadheader driver and No.2 air curtain in front of the transfer point. No.1 air curtain has a unique umbrella structure under the suction of the air duct which can shield the heading dust in the limited area of the heading end. No.2 air curtain can separate the dust at the transfer point from the driver's area of the roadheader to ensure that the driver's area is not polluted by the dust of the transfer point. The annular radial rotating jet generated by the double radial swirl shielding ventilation of the fully mechanized heading face can form a stable swirl in the cross section of the heading, and the velocity distribution in the whole section is uniform. Compared with the radial air curtain generated by the traditional wall-mounted ventilation duct, it has higher strength and dust prevention efficiency. The double radial swirl shielding air curtain can effectively isolate the two main dust sources (dust produced by the roadheader and the dust from the transfer point) of the fully mechanized heading face from the driver's area of the roadheader, preventing the dust from spreading to the driver's area, providing a good working environment. The blowing and suction volume ratio is an important parameter that effects the dust control effect of the ventilation mode. Dust concentration at the driver's position decreases first and then increase with the increase of the blowing and suction volume ratio, and reaches the lowest value when the blowing and suction volume ratio is 1.5.