摘要
为设计和优化面粉输送设备,应用离散元法对面粉进行准确地工程建模和分析,需要对其接触参数进行必要的标定。该研究依据颗粒缩放理论,用“Hertz-Mindlin with Johnson-Kendall-Roberts”接触模型表征面粉颗粒间黏性的影响,提出了一种基于静/动态休止角的接触参数标定方法。运用正交试验方法,对接触参数的敏感性和方差分析,表明面粉颗粒间的滚动摩擦系数、面粉颗粒与不锈钢表面间的静摩擦系数、表面能对静态休止角的影响极显著(P<0.01),并且多组接触参数都可以模拟出与试验相同的静态休止角。进一步研究表明,面粉颗粒与不锈钢表面间的静摩擦系数的合理取值范围为0.2~0.4。通过2种填充率、4种转速下基于动态休止角的参数标定,将其中与试验最为吻合的一组参数作为标定结果,其值如下:面粉颗粒之间恢复系数为0.6、面粉颗粒之间静摩擦系数为0.2、面粉颗粒之间滚动摩擦系数为0.1、面粉颗粒与不锈钢容器表面之间恢复系数为0.6、面粉颗粒与不锈钢容器表面之间静摩擦系数为0.6、面粉颗粒与不锈钢容器表面之间滚动摩擦系数为0.5、表面能为0.12 J/m^(2)。使用该组参数对矩形容器中物料自由坍塌试验进行仿真,其结果与试验结果相符,验证了该标定方法的有效性。该研究提出的标定方法简单、易执行,对粉料输送设备的设计及优化具有一定的工程应用价值。
Accurate engineering modeling of flour is often required for the calibration of its contact parameters in flour conveying systems.In this study,a typical calibration of contact model parameters was proposed to consider the effects of cohesion between flour particles and particle size,according to the static and dynamic angle of repose.Hertz-Mindlin with Johnson-Kendall-Roberts(JKR)contact model was also selected using the particle scaling theory.The orthogonal simulation tests were carried out to implement the sensitivity and variance analysis of the contact parameters using the discrete element method(DEM)model.The result showed that there were the most significant effects of JKR surface energy,the powderpowder coefficient of rolling friction,and the powder-steel coefficient of static friction on the static angle of repose.Since the contact parameters were calibrated only by static angle of repose,the cross-effects of multiple parameters were verified as well.Different combinations of contact parameters produced a similar effect of static angle of repose.Furthermore,five sets of contact parameters were selected to obtain a unique set of parameter values as the candidates.Their simulation from the static angle of repose was the closest related to the test.Then the dynamic stacking was further studied.The flour was filled in a cylindrical container with a transparent bottom and stainless-steel side.In the tests,the cylindrical container was set as 100 mm in diameter and 30 mm in height and then rotated around the axis at the given speed.The camera was used to record the dynamic angle of repose,which was defined as the maximum tilt angle between the slope and the horizontal plane before the powder collapsed.The contact parameters calibrated by the dynamic angle of repose were also verified under the condition of a single filling rate and a single rotational speed.Therefore,the dynamic angle of repose was further calibrated at the filling rates of 0.2 and 0.4,respectively,while the rotational speeds of 30,40,50,and
作者
陈硕
江礼坚
林谢昭
唐旭晟
刘晓敏
张龙
CHEN Shuo;JIANG Lijian;LIN Xiezhao;TANG Xusheng;LIU Xiaomin;ZHANG Long(School of Mechanical Engineering and Automation,Fuzhou University,Fuzhou 350116,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2024年第11期69-76,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家科技部创新方法工作专项(2020IM010200)。
关键词
离散元
正交试验
面粉
接触参数标定
静/动态休止角
discrete element method
orthogonal test
flour
contact parameters calibration
static and dynamic angle of repose
