基于DEM-CFD耦合的谷物多级风选模拟研究

Simulation research of grain multi-stage wind selection based on DEM-CFD coupling

为提高谷物风选效率,强化谷物风选效果,得到最佳风选参数,设计一款多级风选装置,采用离散单元法(DEM)与计算流体力学(CFD)耦合的方法,对多级风选过程进行仿真,并引入谷粒体积浓度来量化风选结果,讨论风速和吹风倾角对谷粒体积浓度的影响。结果表明,经过多级风选之后,谷粒体积浓度可达97.18%,相对初始混合状态而言,提高50.97%,并测得谷粒损失率为4.72%。风速和吹风倾角对风选结果有很大影响,风速为8 m/s,吹风倾角为0°时,可以得到较高的谷粒体积浓度,同时有较小的损失率。

In order to improve the efficiency of grain wind selection, strengthen the selection effect, and obtain the best wind selection parameters, a multi-stage wind selection device is designed, and the method of coupling discrete element method(DEM) and computational fluid dynamics(CFD) is adopted. The multi-stage wind selection process is simulated, and the rice volume concentration is introduced to quantify the wind selection results. The effects of wind speed and wind blowing angle on rice volume concentration are discussed. The results show that after multi-stage wind selecting, rice volume concentration can reach 97.18%, which is 50.97% higher than initial mixing state, and the rice loss rate is 4.72%. The wind speed and blowing angle have great influences on wind selection results. When wind speed is 8 m/s and blowing angle is 0°, a higher rice volume concentration can be obtained, and there is a smaller loss rate.