关键词: 谷物颗粒物料, 落料堆积, 等效介电特性, 数值模拟

Abstract: The basic research on electromagnetic effect of agricultural materials has good application value in microwave-assisted application and device design.  Based on properties of cereal grains, this paper presented a novel method for modeling and numerical analysis, which combined discrete element method, finite element method and average energy method. The feasibility, validity and accuracy of the model were verified by numerical simulation and experimental measurements. The real and simulated results showed that the repose angle error of rice particle materials was 0.45%, and the maximum error between the numerical results of effective dielectric properties obtained by the simulation model and the experimental measurements were less than 5.0% in the calculation conditions of dielectric constant (2.0~10.0), dielectric loss factor (0.1~0.9), microwave frequency（2.0~11.7 GHz）, moisture content (2.0%～19.7%) and volume fraction (18.2%～88.0%) of the cereal grain materials. This study provided basis for microwave processing and nondestructive sensing of cereal grains, and also provided  reference  for the simulation of dielectric properties of other kinds of granular agricultural products.

Key words: cereal grains, free-fall accumulation, effective dielectric properties, numerical simulation