基于降温润湿的深松铲尖材料表面润滑减阻试验研究OA

As an important measure of conservation tillage technology,subsoiling tillage is a necessary means to reduce mechanical compaction of the plow layer soil and break the plough layer.Long-term agricultural production practice has found that issues such as high resistance and energy consumption in subsoiling tillage have limited the widespread promotion and application of subsoiling technology.The current drag reduction technology of subsoiling tillage is mainly divided into two categories:one is bionic structure improvement technology such as microstructure optimization or laser processing of subsoiling shovel tip,and the other is active drag reduction technology with load liquid lubrication medium or vibration source.The technical difficulty and high manufacturing cost seriously restrict the engineering promotion and practical application of subsoiling tillage and drag reduction technology,which is not conducive to the promotion of sustainable agricultural development.Therefore,in this work,scanning electron microscopy(SEM),surface profiler and contact angle tester were adopted to determine the elemental composition,surface profile and contact angle of three commonly used subsoiling shovel tip materials(45 steel,65Mn steel and ductile iron),and the specific characteristics of the materials were clarified.Furthermore,based on the actual production conditions of subsoiling tillage and in consideration of the high temperature and high humidity characteristics of tillage soil,the visual low temperature test platform and the constant temperature and humidity environment control system were used to observe the cooling and wetting(surface temperature of 5,0℃)and freezing(surface temperature of-5,-10,-15℃)processes of materials on the surface of subsoiling shovel tip under simulated soil temperature and humidity conditions,which was to explore the law of surface cooling and wetting behavior of subsoiling shovel tip materials under simulated soil temperature and humidity conditions.In addition,the effect of different surface temperatures(surface temperatures of 18,5,0,-5,-10℃)on the friction coefficient of the material surface was tested by the comprehensive tester for material surface properties and environmental control system,and the suitable material was selected and the optimum temperature conditions were determined.Through the field test of the developed components,the effect of lubrication and rent reduction was verified.The internal mechanism between material properties and wetting film formation and friction drag reduction was revealed.Under the condition of 0℃,the coverage of 45 steel material was 48.24%at 220 s,which was 9.72%and 2.94%higher than that of 65Mn steel and ductile iron.At the same cold surface temperature,the number of condensed droplets of each material gradually decreased and the radius increased significantly along with time.Under the same environmental conditions,at-5℃,the freezing time and complete freezing time on the surface of 45 steel and 65Mn steel were shortened by 42.86%,21.74%and 35.71%,13.04%,respectively.The decrease of the surface temperature of the material could reduce the friction coefficient,and the surface temperature with the largest decrease was 0℃.Compared with the surface temperature of 18℃,the friction coefficients of 45 steel,65Mn steel and ductile iron decreased by 78.87%,65.69%and 65.07%,respectively.The field test showed that the tillage resistance of the developed cooling,wetting,lubricating and drag reduction deep loosening parts was reduced by 30.02%.This work provides an implementation strategy for the lubrication and drag reduction operation of subsoiling tillage by combining the improvement of the current subsoiling shovel tip structure and configuring the temperature control system.This method can reduce the friction coefficient of subsoiling shovel tip material with low cost and high efficiency,providing theoretical and technical support for drag reduction and efficiency improvement of subsoiling tillage.