Numerical simulation approach to predict the abrasion rate of rice during milling

Abstract

The effect of the rice movement and the forces acting on rice grains during abrasion in a mill is unclear limiting the development of rice milling machines. The aim of this work is to provide a numerical methodology for predicting the abrasion rate of rice to provide the basis for the design and use of rice mills and improving milling quality and efficiency. Here, the milling process was investigated experimentally in a laboratory using a vertical mill to identify the dominant abrasion mechanism and to the analyse of particle size distributions. In order to evaluate the abrasion rate, the effect of rotational speed of the roller shaft on the normal force and the sliding distance between particles and particle-geometry was examined using the discrete element method. Abrasion rate calculated according to the Archard abrasion equation from the simulation results and this agreed well with the experiment results thereby validating the feasibility of numerical-experimental approach. The relationship between rotational speed and abrasion rate was established based on polynomial fitting.