利用牛粪生产垫料的滚筒结构优化

Structure optimization of a drum recycling solid cow manure as bedding

针对滚筒发酵生产牛粪垫料过程存在的内部抄板结构不合理、生产效率低、垫料品质差等问题,采用试验与离散元仿真相结合的方法,对滚筒发酵生产垫料过程的牛粪颗粒运动进行研究,并就滚筒内部抄板结构为2组螺旋线排布且抄板与滚筒中轴线夹角(θ)为0°,2组螺旋线排布且θ=45°和4组螺旋线排布且θ=45°时,固体牛粪在滚筒内的滞留时间及混合状态进行仿真分析。结果表明:1)离散单元法能较好地描述滚筒发酵生产牛粪垫料过程;2)抄板结构为4组螺旋线排布且θ=45°时,牛粪颗粒在滚筒内的轴向运行速度为1.7×10^(-4) m/s,较采用其他2种抄板结构时牛粪颗粒轴向运行速度快,此时牛粪在筒仓内的滞留时间为16.2h,满足牛粪垫料生产要求且滚筒生产效率较高。综上,根据离散元仿真结果,可确定滚筒内抄板的最优结构为4组螺旋线排布且夹角θ为45°。本研究为滚筒发酵生产牛粪垫料的结构优化、品质改进及生产效率的提高提供了理论依据。

In order to solve the problems such as unreasonable structure of grabbing planks,low production efficiency and poor quality of bedding material existing in the process of drum fermentation,this study combined a field test with discrete element simulation to explore the particle movement during the process of using the solid cow manure to produce the bedding in the composting-drum.The retention time and the mixing state of solid cow manure in the rotating drum were simulated with two sets of helix arranged and the angle between the plate and the central axis of the roller0°,two sets of helix with an angel of 45°,and four sets of helices with an angle of 45°,respectively.The results showed that:1)The particle movement modelling established by EDEM could describe the movement of the solids manure in the drum-composting process properly.2)The scheme where the structure of four three-dimensional spirals with welding angle 45 oshowed the best performance,with the conveying rate being 1.7×10^(-4) m/s and the fermentation time being 16.2 h,which could achieve a high quality of production efficiency.In conclusion,the structure of the grabbing planks which were arranged in four sets of helices with an angle of 45°towards the central axle was optimal among the three structures.This study provides a theoretical basis for structural optimization,quality and production efficiency improvement of the solid manure producing by composting-drum in large-scale dairy farms.