残膜机械回收作业中压包成型机理的研究

The pollution of residual plastic film has already posed serious threat to the sustainable development of agricultural production environment in Xinjiang. The residual plastic film collected by machine is usually unloaded in the field and shaped as sliver. The loose residual plastic film can cause high transportation cost for centralized treatment. If it is burned, the "twice pollution" and resources waste of film will occur at same time. So, the method of residual plastic film compression and modeling is brought, and its core working mechanism will be studied in this project. At first, the relationship of compression and density will be clear after the compression properties being studied. The main factors which affecting compression performance will be found out, and the influence law will be revealed at same time. Secondly, the constitutive equation of creep and stress-relaxation characteristics will be established after the rheological properties of molding square bag being studied. Then, the main factors which affecting the relaxed density and durability will be found out, and the influence law will also be revealed . At last, we will take a multi-factors orthogonal test to make clear the best compressing and molding conditions, and realize the purpose of decreasing energy consumption and improving efficiency when the working quality is guaranteed. This project will provide theoretical basis for the research and development of modeling machine for residual plastic film.

残膜污染已严重威胁到新疆农业生产环境的可持续发展。残膜在机械回收过程中常以集条（堆）形式卸料于田间、地头，其质地松散，集中处理运输成本高，就地焚烧易造成“二次污染”且浪费地膜资源。为此，本项目提出对残膜进行压缩打包处理，并对其核心的压包成型机理展开研究。首先拟通过开展残膜压缩特性研究，明确残膜压缩力-压缩密度关系，找出影响压缩作业性能的主要因素并揭示影响规律。随后研究成型方包的流变特性，建立残膜压包的蠕变和应力松弛本构方程，明确影响松弛密度和耐久性的主要因素及影响规律。在上述研究基础上进行多因素正交试验，得到残膜压包成型最优工作条件，实现最优打包品质的同时最大化降低能耗和提高打包效率，为残膜打包机具的研制提供理论依据。

残膜污染已严重威胁到新疆农业生产的可持续发展，研制残膜回收机械已成为相关科研机构与农机企业的工作重点。残膜在机械回收过程中常以集条（堆）形式卸料于田间、地头，其质地松散，集中处理运输成本高，就地焚烧易造成“二次污染”且浪费地膜资源。.本项目提出对机收残膜进行压缩打包处理，并以揭示其压包成型机理为目的，针对残膜压缩流变特性及影响因素展开深入研究，采取理论建模、试验验证交叉结合的模式，最终得到最优工艺参数组合，以期达到较好的打包成型效果，主要研究内容和成果如下：.（1）研究并搭建了卧式残膜压包成型试验台，集成设计了压缩装置机械结构与电控系统，使压缩速度、保压时间等试验因素更接近实际作业条件，为模拟非生物质农业物料压缩作业工况提供了硬件基础。.（2）研究了残膜压缩特性，建立了残膜压缩过程中压缩应力与压缩位移关系模型，揭示了压缩截面形状、截面积、最大压缩力、含杂率、含水率、含土率、喂入量等因素对残膜压缩特性的影响规律。.（3）研究了残膜成型方包流变特性与最佳作业工艺参数，以抗跌碎性、松弛比和比能耗为试验指标，探究不同影响因素对残膜压包成型过程流变特性和残膜压块自然松弛过程的影响规律，建立各影响因素与松弛比、比能耗的数学模型；通过多因素台架试验，获得了作业参数最优组合，即最大压缩力13.53MPa，保型时间30s，喂入量1000g，压缩速度30mm/s。.（4）研制了残膜压包成型系统装置。开发了双泵加载液压系统与基于PLC的压包成型控制系统，通过系统集成形成样机，田间试验结果表明：机具作业过程中各部件运转顺畅，未出现卡顿、停滞现象，残膜压包成型成功率达88%，单包成型时间仅需38.6s，具有良好的作业性能。.本项目对非生物质农业物料的压缩特性研究具有参考意义，同时为农田残膜回收打包装备的结构设计与作业参数优化提供理论支撑。