仿生波纹形开沟器减黏降阻性能测试与分析

Measurement and analysis on reducing adhesion and resistance of bionic ripple opener

针对现有普通开沟器在工作过程中易粘土、阻力大等问题,提出一种仿生波纹形开沟器。该仿生开沟器依据土壤动物与生俱来的减黏脱土特性和超高分子量聚乙烯优异的减黏性能,在原有普通开沟器基础上进行设计制造。该文通过田间试验,将牵引阻力设为试验指标,使用正交设计检验仿生开沟器相对于普通开沟器减黏降阻的效果和探究仿生开沟器非光滑表面形态的减黏降阻机理。试验表明,仿生开沟器减黏降阻的效果高于普通开沟器9%左右;入土深度是影响开沟器牵引阻力的主要因素,其次是土壤湿度,工作速度影响最小;通过3因素4水平正交组合试验得出使用仿生开沟器的最优条件:土壤湿度达到16.3%,入土深度有6 cm,工作速度为1.8 km/h。仿生波纹形开沟器具有良好的减黏降阻效果,为后续的仿生开沟器或其他触土部件研究提供参考。

Traditional furrow openers are lack of the ability of reducing resistance and clay adhesion. Hence, a kind of new bionic opener was designed and manufactured here based on characteristics of adhesion and resistance reduction of soil animals and ultra-high molecular weight polyethylene. Its tractive resistance was tested and compared with that of a traditional opener in an orthogonal （three factor and four level） designed field experiment in order to study the viscosity drag reduction mechanism of the bionic opener with non-smooth surface. Experimental results showed that clay adhesion on the traditional opener was not found when soil humidity was less than 16.3%, but obvious when soil humidity was more than 20.8%, while the adhesion on the bionic opener was little regardless of soil humidity. The tractive resistance of the bionic opener increased with increasing soil humidity when soil humidity was in a certain range. It was apparent that the traction resistance was mainly affected by the trenching depth, the soil humidity, and the forward velocity. Based on the related theory, the only velocity magnitude changes and the tractive resistance should be unaffected when the tractor is in a state of uniform motion. The impact of forward velocity on traction resistance and clay adhesion might because a number of conditions could not be completely controlled during the field test. In conclusion, the bionic opener was better in reducing adhesion and resistance than the traditional openers probably because：1） the contact area with soil was smaller in the former than in the latter;2） the former had corrugated non-smooth shape, which could form a cavity when contacting with the soil, result in a higher normal adhesion than tangential adhesion, destroying the adhesion interface and reducing the resistance; and 3） the former could cause larger stress fluctuation than the latter, and the fluctuation could partly destroy the continuity of the soil so that the barricade blocking and compaction were not easily formed. Furthermore, the bionic opener could work best in an optimal condition with soil moisture of 16.3%, the trenching depth of 6 cm and the forward velocity of 1.8 km/h.