基于MATLAB的浅圆仓内玉米沉降运动特性分析

Analysis of the falling kinematic characteristic of corn in silo based on MATLAB

粮食进入浅圆仓后立即进行沉降运动,达到仓底后进行堆积运动,较高速度的粮食颗粒在堆积运动时会引起一系列的问题。从运动学角度分析了玉米颗粒在仓内的沉降运动,并使用MATLAB软件模拟了不同下落高度、初速度、粮堆组分及质量流量对颗粒沉降运动基本参数的影响。结果表明:当进粮初速度为0时,玉米颗粒历经3.45 s、沉降距离35.86 m达到最大速度即沉降速度14.51 m/s;当下落高度足够大时,玉米颗粒的下落速度增大到一定值后不再增加,开始匀速下落;玉米颗粒入仓时的初速度越大,会在更短的时间内达到沉降速度,加速段的沉降距离越小;粮堆的不同组分沉降速度不同,在相同时间内各种组分的下落距离不同;随着质量流量和下落高度的增加,颗粒群沉降时的诱导气流量不断增大,颗粒群沉降运动时的沉降速度低于单颗粒的。研究结果可为浅圆仓入仓清理工艺、辅助装置的设计、优化等提供理论依据。

When grains enter the shallow silo,complex motion will occur.The motion is divided into two parts:One part is the movement of grain particles in the air,and the other part is the movement of particle on the small heap formed.This study analyzed the falling movement of corn particles in the silo from the perspective of kinematics.Meanwhile,MATLAB software was used to simulate the effects of different falling height,initial velocity,grain composition and mass flow rate on the basic parameters of particle falling movement.The results were as follows:For a certain variety of corn granules with zero initial velocity,the time required to reach the maximum speed in the falling process was 3.45 s.The speed at the moment was the settling speed,which was 14.51 m/s,and the settling distance of the grain was 35.86 m at this moment.When the falling height of particles was large enough,the falling speed of particles would not increase after increasing to a certain value and start to fall at a uniform speed,and the settling speed would be reached,which was the terminal velocity.In the process of grain particles entering the shallow silo,the larger the initial velocity of particles,the shorter the time it reached the settling speed,and the shorter the particle movement distance.In the process of falling,the settling speed of different components in grain was different,and the falling distance of various components was different at the same time.In the process of grain particles entering the silo,with the increase of mass flow rate and falling height,the air entrainment during the falling of grain particle group increased continuously.Compared with a single particle,the settling velocity of the particle group during the falling process was smaller.The research results can provide theoretical foundation for the cleaning process of silo and the design and optimization of auxiliary devices.