Numerical studies of pulsing airflow separation of fine coal based on Euler-Lagrange method

It is difficult to simulate the pulsing airflow separation process of fine coal accurately using the conventional numerical model,such as Eulerian Model and Discrete Phase Model. The Dense Discrete Phase Model (DDPM) of the pulsing airflow separation process of fine coal was proposed based on the volume fraction of discrete phase and Soft- sphere approach to account for the influence from the volume of particles and the forces that result from the collision of particles. The distribution of the flow field and the separation results of 6-3 mm coal particles in pulsing air classifier were simulated through numerical simulation and continuous separation experiments in laboratory. The results show that DDPM was suitable for the simulation of the pulsing airflow separation process of fine coal and it was effective to show the perturbation action on the distribution of the flow field from particle phases. The separated materials had a significant impact on the distribution of the flow field,particularly on the velocity distribution and the change of pres- sure drop. Moreover,the greater handling capacity of the pulsing air classifier,the more significantly change of pressure drop. Within the scope of experiment conditions,the root-mean-square error of partition coefficients of heavy product in different density fractions was less than 3% by the method of DDPM,and the greater handling capacity,the higher separation density when the blowing rate was constant.