Study On The Material-Sieving Properties Of The New-Model Hammer Mill

Hammer mill is one of the most widely used machine for feed grinding. Normally the traditional hammer mill has the problem of material-air circulation lay, causing the low sieving efficiency, higher energy consuming and material over- grinding.A new-model hammer mill was developed by our research group in the earlier work, in which the problems caused by the materials-air circulation lay had been solved, but the material sieving efficiency was still low. In this paper, the simulation and test on the air-flow field in the material-sieving device of the new-model hammer mill were conducted. It is concluded that there are turbulent flow and reversed flow in it, especially at the corner area, the air velocity near the side of the feeding part is higher than the other side, and the sieving efficiency is related to the corner.The Mixture model in software FLUENT6.3 was used to simulate the air-solid two-phase flow in the material-sieving device, showing that the solid phase distribution is un-uniform, the particles are mainly accumulated in inlet and the inside of the sieve, which cause the difficulties in separating the material , or even the blocking of the material. The negative pressure in outlet causes the turbulent flow, which is unfavorable for the separating of the materials, and bigger particles are more difficult to be sieved. Particle diameter has less influence on sieving properties than the particle content.