水稻秸秆深埋整秆还田装置设计与试验

针对目前我国水稻秸秆还田机械普遍存在的耕作深度浅、秸秆还田深度不满足农艺要求、旋耕部件缠草严重等问题,运用旋耕理论和数值计算分析方法设计了水稻秸秆深埋整秆还田装置。根据实际情况对土壤颗粒进行假设,运用离散元法建立土壤颗粒力学模型,应用EDEM软件进行整秆还田仿真虚拟试验,仿真结果表明,耕深在20 cm时,土壤表层覆盖率为93.87%。通过土槽台架试验得到:在作业速度为1.25 km/h、刀辊转速为237 r/min时,耕深可达到22 cm,地表以下15~20 cm翻埋的秸秆占秸秆总量的80%,秸秆还田率为91.63%,同时刀辊轴不缠草。试验结果表明,秸秆还田深度达到水整地环节的要求,秸秆还田率较高。通过虚拟仿真和台架试验相互验证,证明新型整秆还田装置一次作业可实现切土、碎土、埋草、压草及覆土的功能,满足农艺要求。

Design and Experiment of Rice Straw Deep Buried and Whole Straw Returning Device

At present, some problems of rice straw returning machine still exist in China, such as shallow tillage depth, straw counters field depth can not meet the agronomic requirements, and rotary parts are easy to winding straw, etc. A new kind of rice straw deep buried and whole straw returning device was designed by using the rotary tillage theory and numerical calculation analysis. With the hypothesis of soil particles based on the actual situation, the mechanical model of soil particles was established and the simulated virtual experiment of whole straw returning device was carried out by applying the discrete element method (EDEM). As a result, the coverage rate of topsoil reached 93.87% when the tilling depth was 20cm. By the soil bin bench tests, the following results were obtained: when the operation speed was 1.25km/h and the speed of knife roller was 237r/min, the tillage depth could reach 22cm; straws buried below the surface in 15~20cm accounted for about 80% of the total straw; the topsoil coverage rate was 91.63%; and the knife roller shaft would not wrap the straws. The test results showed that straw buried depth can meet the requirements of paddy field tillage link and the topsoil coverage rate was high. Through the mutual verification between virtual simulation and bench test, it is proved that the design of whole straw returning device could realize the functions of cutting soil, breaking soil, burying grass, pressing grass and covering soil, which meets the agricultural requirements well.