膨化颗粒饲料碰撞破碎特性分析与离散元模拟仿真

为了探究在气送过程中碰撞对膨化颗粒饲料的影响,以鲈鱼膨化颗粒饲料为研究对象,通过试验和仿真共同模拟膨化颗粒饲料的碰撞破碎状况,探究其破碎机理与破碎规律。采用水平碰撞试验平台,探究不同碰撞速度对膨化颗粒饲料的破碎影响,并采用破碎函数建立破碎尺寸与碰撞速度的拟合关系,参数拟合的决定系数大于0.99。将膨化颗粒饲料破碎状态划分为：未破碎、局部破碎、破碎和崩解4种状态,测得试验中临界碰撞速度为25.60 m/s,相对应的气流速度为56.29 m/s。采用离散元法(DEM)建立膨化颗粒饲料的离散元模型并进行参数标定。基于EDEM软件,模拟碰撞破碎过程得到仿真中临界碰撞速度25.20 m/s,试验与仿真得到的临界破碎速度相差1.6%。在EDEM后处理中获得碰撞速度与破碎率和最大尺寸率的关系以及破碎率与损失能量的关系,随着速度的增加,破碎率增加,而最大尺寸率减小。破碎率先呈线性变化而后呈指数变化,但最大尺寸率一直呈指数变化,且在两线的交点25.20 m/s左右出现断崖式下降。当碰撞速度小于25.20 m/s时,破碎率与损失能量呈线性关系,到达临界破碎速度后,损失能量呈指数变化。研究结果可为解释膨化颗...

Impact Breakage Characteristics and Discrete Element Simulation of Extruded Pellet Feed

With the aim to explore the influence of collision on extruded pellet feed during air delivery, perch extruded pellet feed was taken as the research object to simulate the collision and breakage of extruded pellet feed through experiments and simulations, exploring the breakage mechanism and law. The horizontal collision test platform was used to explore the influence of different collision speeds on the breakage of extruded pellet feed, and the breakage function was used to establish the fitting relationship between breakage size and collision speed. The determination coefficient of parameters fitting was greater than 0.99. The breakage state of extruded pellet feed was divided into four states, unbroken, partially broken, broken, and disintegrated. The critical collision velocity was 25.60m/s, and the corresponding airflow velocity was 56.29m/s. The discrete element model of extruded pellet feed was established by discrete element method (DEM) and the parameters were calibrated. Based on EDEM software the critical breakage speed of 25.20m/s was obtained by simulating the collision breakage process, and the difference between the critical speed obtained by experiment and simulation was 1.6%. In the EDEM post-processing, the relationships between the collision speed and the breakage rate and the maximum size ratio were obtained. As the speed increased, the breakage rate was also increased. However, the maximum size ratio was decreased. The relationship between the breakage rate and the energy loss was also obtained. The figure of breakage rate showed linear change first, and then exponential change. But the maximum size rate was the exponential change. And in the intersection of the two lines at about 25.20m/s cliff-like declined. When the collision speed was less than 25.20m/s, the breakage rate was linearly related to the loss energy. After reaching the critical breakage speed, the loss energy was changed exponentially. The results provided data support and theoretical reference for explaining the breakage mechanism of extruded pellet feed.