炒青绿茶离散元仿真参数标定研究

Calibration of Simulation Parameters for Roasted Green Tea Based on Discrete Element Method

摘要:

针对炒青绿茶精制装备仿真分析中缺少准确的离散元仿真参数问题，以炒青绿茶为研究对象，标定炒青绿茶离散元仿真关键参数。通过斜面法与自由落体法对茶叶-茶叶和茶叶-钢板之间离散元参数进行研究，确定静摩擦因数、滚动摩擦因数和碰撞恢复系数的取值范围。通过提升法台架试验获得炒青绿茶实际堆积角，建立炒青绿茶离散元模型，模拟堆积角形成过程。以炒青绿茶实际堆积角为响应值，使用Plackett-Burman试验筛选出对炒青绿茶堆积角有显著影响的参数，通过最陡爬坡试验获取近似最佳响应范围，最后通过Box-Behnken获得影响显著参数最优组合。结果表明：当剪切模量为2.930MPa、茶叶-茶叶静摩擦因数为0.771、茶叶-茶叶滚动摩擦因数为0.133、茶叶-茶叶碰撞恢复系数为0.354时，炒青绿茶仿真堆积角为30.12°，与实际堆积角误差为1.59%，表明可以采用优化标定参数模拟炒青绿茶外部接触特征。

Abstract:

Aiming to lack of accurate discrete element simulation parameters in the simulation analysis of roasted green tea refining equipment, taking roasted green tea as the research object, the discrete element simulation parameters of roasted green tea were calibrated. The contact parameters between roasted green tea and materials were measured by using the inclined plane method and the free fall method to determine the range of values for static friction coefficient, rolling friction coefficient, and collision recovery coefficient. The actual stacking angle of roasted green tea was obtained through bench tests of the cylinder lifting method. A discrete element model of roasted green tea was established, and the formation process of stacking angle was simulated. Using the actual stacking angle of roasted green tea as the response value, the Plackett-Burman experiment was used to screen out the parameters that had a significant impact on the stacking angle of roasted green tea. The steepest climb test was used to approximate the optimal response range, and finally the optimal combination of significant influencing parameters was obtained through Box-Behnken. The results showed that when the shear modulus was 2.930MPa, the coefficient of static friction between tea particles was 0.771, the coefficient of rolling friction between tea particles was 0.133, and the coefficient of collision recovery between tea particles was 0.354, the simulated stacking angle of roasted green tea was 30.12°, and the error with the actual stacking angle was 1.59%. The optimized calibration parameters can be used to simulate the external contact characteristics of roasted green tea.