Abstract: Aiming at the lack of accurate model parameters in the discrete element simulation of needleshaped tea in the process of stripping machine, which leads to the problem of distortion in the simulation of discrete elements of tea stripping machine, the singlebud tea granules are used as the research object, and the particle model is established based on the approximation method of slicing technology, and the discrete element simulation and the funnel injection method accumulation test are used to calibrate the simulation parameters. Taking the rest angle of tea particles as the response value, the PlackettBurman experiment obtained parameters that had a significant impact on the rest angle of tea particles: collision recovery coefficient between tea particles, static friction coefficient between tea particles and rolling friction coefficient between tea particles. Taking the relative error between the simulation test rest angle and the actual accumulation test rest angle as the goal, the steepest climb test determined the optimal value range of the significance parameter, and the quadratic polynomial equation between the tea particle rest angle and the significance parameter was established by the BoxBehnken test, and the optimal value of the significance parameter was obtained by using the DesignExpert software optimization module: the collision recovery coefficient between tea particles was 0.28, the static friction coefficient between tea particles was 0.15 and the rolling friction coefficient between tea particles was 0.10, and the discrete element simulation verification of the calibration results showed that the average rest angle of tea particles obtained by simulation was 19.52°, which was 3.51% compared with the actual average stop angle of tea particles 20.23°, indicating that the calibration results of this parameter were reasonable and effective. It provides a certain theoretical reference for the optimal design of tea baring machine and the numerical simulation process of tea processing.

Key words: stacking test, needleshaped tea, discrete element simulation, parameter calibration

摘要： 针对针形茶叶在理条机加工过程中离散元仿真缺少准确的模型参数，导致茶叶理条机离散元仿真过程中易出现失真问题，以单芽茶叶颗粒为研究对象，基于切片技术的近似法建立颗粒模型，采用离散元仿真与漏斗注入法堆积试验相结合的方法，对其仿真参数进行标定。以茶叶颗粒的休止角为响应值，设计PlackettBurman试验得到对茶叶颗粒休止角有显著性影响的参数：茶叶颗粒间碰撞恢复系数、茶叶颗粒间静摩擦系数和茶叶颗粒间滚动摩擦系数；以仿真试验休止角和实际堆积试验休止角之间的相对误差为目标，进行最陡爬坡试验确定显著性参数的最优值范围，并通过BoxBehnken试验建立茶叶颗粒休止角与显著性参数之间的二次多项式方程，利用DesignExpert软件优化模块得出显著性参数最优值：茶叶颗粒间碰撞恢复系数0.28、茶叶颗粒间静摩擦系数0.15、茶叶颗粒间滚动摩擦系数0.10；并对标定的结果进行离散元仿真验证，结果表明：仿真得到的茶叶颗粒休止角均值为19.52°，与实际茶叶颗粒休止角20.23°相比，相对误差为3.51%，说明此参数标定结果合理有效。为茶叶理条机的优化设计及茶叶加工数值模拟过程提供一定的理论参考。

关键词: 堆积试验, 针形茶叶, 离散元仿真, 参数标定