水田高茬秸秆旋耕翻埋机理及其多场耦合机制的研究

The stalk remained in field became higher and higher after harvesting preceding crop in major rice production regions of China, and it was difficult to plow for straw returning. Most of the straws were been burnt which caused pollution to the environment. Using rototilling for the higher straw returning instead of plowing had advantages, but the principle of rototilling for the higher straw returning was unknown, and there were many factors which influenced the working quality and power consumption, also lacked of inspection methods for power consumption, so the study on the rationality, power performance and economy of structural parameters still rested on the stage of qualitative analogy and indoor soil bin tests, the deeper theoretical research and field experimental verification were in urgent need. In this research project, taking the tillage machine of rototilling for the higher straw returning in paddy field which was independent innovated as the study object, combination of bidirectional-opposed helical rotary roller will be the research emphases, and the mechanism of rototilling for the higher straw returning will be investigated by using the methods of virtual simulation, finite element analysis, virtual detection and high speed photography. The multi-field coupling mechanism of implement, straw, soil and water will be revealed, the mechanism of uniform mixture of straw and soil will be illustrated. The influencing factors of power consumption and the effect regularity will be studied; the power consumption models will be established. The structural parameters, working parameters and performance parameters will be optimized. The methods of effective utilization and energy saving under different field conditions will be elucidated. These research works mentioned above will provide theoretical foundation and practical basis for industrialized application of the technology of rototilling for straw returning, and this technology has the functions of energy saving and environment protection.

我国水稻主产区前茬作物收获后，残留田间的秸秆越来越高，犁耕难以翻埋，绝大部分就地焚烧，严重污染生态环境。虽然旋耕翻埋已显替代优势，但由于秸秆翻埋机理不明，影响作业质量和能耗因素多；功耗检测手段匮乏，对机具结构性能参数的合理性、动力性、经济性的深入研究，还停留在定性类比和室内台架试验阶段，迫切需要深化理论研究和田间试验验证。本项目旨在以自主创新的水田高茬秸秆旋耕翻埋耕整机为对象，以组合双向对置螺旋刀辊为重点，基于虚拟仿真、有限元分析、虚拟仪器检测、高速摄影等技术与方法，探讨高茬秸秆耕层旋耕翻埋机理；揭示"机具、秸秆、土壤、水分"多场耦合和秸秆均匀融合泥土的机制；研究影响机具作业功耗的因素及其规律；建立机具功耗特性模型；优化机具结构参数、工作参数和性能参数；阐明不同秸秆土壤条件下有效功率利用和节能降耗方法，为具有节能环保功能的本旋耕埋草原理技术的产业化应用提供理论基础和实践依据。

我国水稻主产区前茬作物收获后，残留田间的秸秆越来越高，犁耕难以翻埋，绝大部分就地焚烧，严重污染生态环境。虽然旋耕翻埋已显替代优势，但由于秸秆翻埋机理不明，影响作业质量，能耗因素多，功耗检测手段匮乏，对机具结构性能参数的合理性、动力性、经济性的深入研究还停留在定性类比和室内台架试验阶段，迫切需要深化理论研究和田间试验验证。.为分析螺旋横刀对秸秆的埋覆机理，课题组对水稻主产区土壤及秸秆进行了物理力学性能测试；建立了 螺旋横刀数学模型，推导出横刀棱边轮廓曲线的静态方程和动态方程，绘制了动态滑切角、动态切土角等主要耕作参数随刀辊位置角的变化规律曲线，对影响高茬秸秆旋耕翻埋效果的主要因素进行了计算分析，结果发现，横刀刃口为螺旋线、静态滑切角为常数、动态滑切角近似为常数的等滑切角切削方式有利于刀辊受力的平稳性，并保持整机耕深的稳定性。.为揭示秸秆还田耕整机的螺旋刀辊与土壤之间的关系特性，根据螺旋刀辊切削土壤的工作特点，利用有有限元分析ANSYS/LS-DYNA软件、离散元EDEM软件和高速摄影技术对螺旋刀辊土壤切削过程进行分析，得出了螺旋刀辊切削土壤功率消耗、切削阻力大小以及土壤秸秆等速度随时间的变化情况。.采用 LabVIEW 软件，结合NI 数据采集卡、动态扭矩传感器和电感式接近开关等组成的硬件平台，设计了功耗检测系统。以耕深、刀辊转速、机组前进速度为影响因子进行田间正交试验，结果表明：影响高茬秸秆还田耕整机作业功耗的首要因素为耕深，其次为机组前进速度和刀辊转速；其较优作业参数为：刀辊转速 330 r/min，耕深185 mm，机组前进速度 3.36 km/h，其平均作业功耗为52.52 kW，秸秆埋覆率达96.2%。.基于上述研究，课题组改进优化水旱两用型秸秆还田耕整刀辊，，设计了可挂接的平地装置，最后对油菜秸秆进行了埋覆还田效应研究。田间试验结果表明：该机具作业后即可实现水田和旱地秸秆埋覆、旋耕碎土、平整地表等多项功能，水田和旱地耕深分别为240mm和179 mm，耕深稳定性分别89.8%和 86.6%，耕后地表平整度均 小于19 mm，植被埋覆率分别为99.8%和97.4%，功耗小于40Kw，作业质量满足水稻播栽对耕整地的农艺要求。该项目的研究为具有节能环保功能旋耕埋草原理技术的产业化应用提供理论基础和实践依据。