玉米秸秆饲料除尘筛出物离散元数值模拟参数标定

为提高玉米秸秆饲料除尘过程中离散元数值模拟参数的准确度，采用物理试验与数值模拟相结合的方法对玉米秸秆饲料的筛出物进行离散元数值模拟参数标定。将物理试验测定筛出物中秸秆与尘土的接触参数作为数值模拟参数选择依据，利用Plackett-Burman试验、最陡爬坡试验和Box-Behnken试验确定对数值模拟休止角影响最显著的因素。以物理试验得到的休止角(41.668°)与标准筛除尘率(13.24%)为目标值，对显著性参数进行寻优；应用最优参数组合进行休止角与标准筛除尘率数值模拟，验证标定参数组合数值模拟精确性。结果表明:对数值模拟休止角影响显著的因素为，尘土接触模型JKR表面能、尘土-尘土恢复系数和尘土-尘土滚动摩擦因数；最优参数组合为，尘土接触模型JKR表面能9.052 J/m²、尘土-尘土恢复系数0.52、尘土-尘土滚动摩擦因数0.182。数值模拟休止角与物理试验休止角相对误差为1.26%，标准筛数值模拟除尘率与物理试验除尘率相对误差为7.93%。

Parameter calibration of discrete element numerical simulation for the dedusting sieve of corn straw feed

In order to improve the accuracy of discrete element numerical simulation parameters in the process of dedusting corn straw feed, a method combining physical experiment and numericaulation parameters of screened corn straw feed. The contact parameters between straw and dust measured by physical tests were used as the basis for the selection of numerical simulation parameters. Plackett-Burman test, steepest climbing test and Box-Behnken test were used to determine the most significant factors affecting the angle of repose of numerical simulation. Taking repose angle(41. 668°)and dust removal rate of standard sieve(13. 24%)obtained by physical experiment as target values, the significance parameters were optimized. The numerical simulation of repose angle and dust removal rate of standard sieve was carried out by using the optimal parameter combination to verify the accuracy of numerical simulation of calibration parameter combination. The results show that the significant factors affecting the numerical simulation rest angle are the surface energy of dust contact model JKR, dust-dust recovery coefficient, and dust-dust rolling friction factor. The optimal parameter combination was obtained as follows: dust contact model JKR surface energy 9. 052 J/m², dust-dust recovery coefficient 0. 52 and dust-dust rolling friction factor 0. 182. The relative error between the numerical simulation repose angle and the physical test repose angle is 1. 26%, and the relative error between the numerical simulation dust removal rate and the standard sieve physical test dust removal rate is 7. 93%.