To improve transport efficiency of coal powders

flow field and coal particles trajectories in HP1163 pulverizer were analyzed with numerical simulation. Most attention was focused on influence of throat structure on the flow field. On this basis

the throat structure was improved. The results show that

changing shielding of the throttle ring in the circumferential direction to the radial direction can increase the horizontal rotation speed of the air flow

and improve the uniformity of the internal flow field of the coal mill. The downward flow in middle of the pulverizer will cause settle down of fine coal particles. The improved throat slows down the downward flow and narrows its extension

which increases the horizontal velocity component of the flow field and shrinks the low velocity zone

so the distribution of velocity is more uniform

which is beneficial to preventing settle down of fine coal particles. The improved throat performs better in reducing pulverizer reject than that with a throat ring.