基于离散单元法的齿辊表面技术参数对制粉功率影响分析

Analysis of the influence of technical parameters of roll surface on milling power based on discrete unit method

目前国内辊式磨粉机齿辊表面技术参数对制粉功率的影响研究仍有空缺,不利于企业降耗增效。设计Box-Behnken四因素三水平试验,以单轴压缩试验实际临界载荷作为响应目标,采用离散单元法,基于Hertz-Mindlin with Bonding模型对小麦Bond模型进行参数标定。再分别对齿角、前角、齿顶宽、齿数以及齿斜度开展Box-Behnken五因素三水平响应面仿真试验,研究表面技术参数对制粉功率的影响。结果表明:根据回归方程得到最优参数为单位面积法向刚度3.61×10^(9)N/m^(2)、单位面积切向刚度1×10^(9)N/m^(2)、临界法向应力1×10^(7)Pa、临界切向应力1×10^(8)Pa;验证离散元仿真临界载荷和回归方程误差率为1.6%,证明了参数标定的可靠性;仿真试验功率的变化趋势与实测功率变化趋势相同,且功率相对误差在13.5%内,证明了仿真分析的可靠性。研究结果可为后续表面技术参数对制粉影响以及其优化研究提供参考依据。

At present,the domestic roller mill surface technical parameters on the impact of powder making research still needs to be improved,which is not conducive to the enterprise′s reduction of consumption and increase efficiency the domestic roller mill roller tooth shape stays in the empirical selection,the tooth shape on the impact of pulverization is still a large lack of.This paper launches the research on the influence of tooth roller tooth shape on pulverizing power.Firstly,the discrete element cell method was used to calibrate the bonding parameters of wheat to enhance the reliability of the simulation to simulate the crushing process of wheat.The discrete element cell method was used to firstly calibrate the parameters of wheat Bond model based on the Hertz-Mindlin with Bonding model,and design the Box-Behnken four-factor,three-level test to take the actual critical load as the response surface target.The optimal wheat particle bonding parameters were calibrated to lay a foundation for the subsequent tooth shape research.Based on the aforementioned calibration and previous research,a discrete element milling model of the grinding roll was established.The Box-Behnken five-factor and three-level response surface simulation tests were carried out for tooth angle,front angle,top width,number of teeth and tooth slope to study the effect of tooth shape parameters on milling power,and the regression equations between tooth shape parameters and power were obtained.The optimal parameters were calculated according to the regression equation:the normal stiffness per unit area was 3.61×10^(9)N/m^(2),the tangential stiffness per unit area was 1×10^(9)N/m^(2),the critical normal stress was 1×10^(7)Pa,and the critical tangential stress was 1×10^(8)Pa.The error rate of the discrete element simulation critical load and regression equation was 1.6%,which proved the reliability of the parameter calibration.This parameter provided a strong support for the subsequent establishment of wheat crushing model.The regression equation of the tooth parameters with the milling power as the response value was obtained,which provides theoretical support for the subsequent tooth-related research,and after the experimental measurements were compared and analyzed with the simulation test,the trend of the simulation test power was the same as the trend of the measured power,and the relative error of the power was within 13.5%,which proved the reliability of the simulation analysis.The crushing model of wheat milling was established by discrete element method,which can realize the simulation of wheat crushing,and the effect of tooth parameters on milling effect was significant.The results of the research can provide a reference basis for the subsequent research on the effect of tooth parameters on milling and optimization of tooth shape.