Study on induced airflow characteristic and dust particle diffusion law at transshipment point

Abstract

ABSTRACT To better solve the problem of dust pollution at the coal transshipment point, the particle tracking calculation method based on the discrete phase model was adopted to study the dynamic three-dimensional flow field of falling dust during coal transshipment. The induced airflow field characteristics and the dust particles migration law at different times and sections were simulated, and the power function relation between the initial falling velocity, falling height, and the induced airflow rate was deduced. The results showed that in the process of coal falling onto the belt, the induced airflow continuously sucked fresh air to form a vortex due to the reduction of vertical static pressure in the vertical direction and self-generated turbulence. The direction of induced airflow at the coal dropping point was different, and the horizontal airflow velocity could reach 1.4 m/s. The spiral migration path of dust particles was formed by the influence of the eddy current. At the same time, under the effect of the negative pressure caused by the induced airflow, the dust particles carried by the coal were emitted from the outlet of the guide trough, and the dust mass concentration was as high as 540 mg/m3. Meanwhile, the induced airflow velocity of falling point increased with the increase of initial falling velocity and coal material falling height, which matched to power function exponents were 1.01 and 0.41 respectively. With the increase of the falling height, more negative pressure air was absorbed into the blanking pipe, which lead to the increase of dust mass concentration in position after the feeding point. The maximum dust mass concentration was 715 mg/m3.