Abstract: Aiming at the problem of unequal mixing of crushed materials and strains in the process of straw fermentation, the parameters of spiral stirring structure of aerobic reactor were optimized. Based on the discrete unit method in the material theory and simulation analysis, the result showed that the primary and secondary order of the influence coefficient of variation was rotational speed, pitch ratio and leaf width ratio. With the increase of stirring leaf width ratio, the value of coefficient of variation was decreased and then increased, and the average power was decreased; with the increase of stirring pitch ratio, the value of coefficient of variation was decreased and then risen, and the average power was fallen; with the increase of stirring rotational speed, the mixing coefficient was fallen, and the average power was increased and then decreased. The coefficient of variation model was constructed and optimized, and the optimal mixing coefficient was 13.295%, and the error with the simulation result was 1.411%. The stirring device was analyzed statically, and the maximum stress value was 47.259 MPa, and the maximum deflection was 4.357 5 mm. The average error between discrete element simulation power and test value was 14.1%, which was in accordance with the design requirements. This stirring device design can provide theoretical support for efficient mixing of fermentation reactor.

Key words:  straw fermentation, spiral stirring structure, discrete element method, coefficient of variation, parameter optimization

摘要： 针对秸秆发酵过程中碎料与菌种混合不均问题，对好氧反应器的螺旋搅拌结构进行参数优化。基于离散单元法，对物料进行理论和仿真分析。结果表明，影响变异系数主次顺序为转速、螺距比、叶宽比；随搅拌叶宽比增加，变异系数先减小后增大，平均功率呈下降趋势；随搅拌螺距比增加，变异系数先下降后上升，平均功率呈下降趋势；随搅拌转速增加，变异系数呈下降趋势，平均功率呈先上升后下降趋势。构建变异系数模型并进行优化，变异系数最优为13.295%，与仿真结果误差为1.411%；搅拌装置进行静力学分析，最大应力值为47.259 MPa，最大变形为4.357 5 mm；离散元仿真功率与试验值误差均值为14.1%，符合设计要求。该搅拌参数优化设计为发酵反应器高效混合提供理论支持。

关键词: 秸秆发酵, 螺旋搅拌结构, 离散单元法, 变异系数, 参数优化