流向引导性微结构超表面设计方法及水润滑机理研究

The increase in friction and wear of water lubricated friction pair under low speed operating condition can result in high consumption of energy, and obvious reduction of life span. In addition, the frictional vibration can bring in severe noise pollution. Thus, study on the reduction of friction resistance and noise is quite necessary. This project proposes a lubricative meta-surface obtained through fabricating hydrophilic micro-structures arranged in a certain direction on the hydrophobic surface. The flow of water can be adjusted to the micro-structures for the existence of different adhesion forces of water on the hydrophobic surface and the hydrophilic surface. Thus, suitable design of micro-structures can control and guide the water, as lubricant, flowing to the high contact pressure zones of the friction interface, thus supplying lubricant to alleviate its oil-starved condition and reducing friction and wear. The study also explores of the enhancement of micro-hydrodynamic pressure and secondary lubrication action of micro-structures caused by hydrophobic/hydrophilic properties of the friction interface, so as to facilitate the development of corresponding model. Meanwhile, the micro-structures are anticipated to make slope of the Stribeck curve gentle in low speed range, and lead to positive equivalent damping coefficient for the tribological system, thus suppressing the excitation of friction noise. Based on the above theories, the shape, dimension and distribution of micro-structures are optimized, and the interaction mechanisms between the parameters of micro-structures and their tribological behaviours are also elucidated, which may provide therotical basis for the application of meta-surface to water lubrication. This project aims to reveal the water lubrication mechanism of the designed meta-surface, and also provides theoretical basis and technical support for improving the tribological performance and reducing friction noise of water lubricated friction pair. In addition, achievements having academic and engineering significance are also anticipated to be obtained in this project.

水润滑摩擦副在低速条件下剧烈的摩擦磨损会增加能耗、缩短寿命，并通过摩擦振动产生严重的噪声污染，因此其减阻降噪研究十分必要。本项目提出超表面润滑设计，通过在疏水表面加工按一定方向排列的亲水性微结构，利用亲疏水表面对润滑水的粘附力差，对水流进行调节，定向引导水流向“乏油”的高应力接触区，使润滑水得到补充，从而改善润滑、减小摩擦磨损。并通过探索表面亲疏水特性对微结构流体动压、二次润滑行为的加强作用，建立微结构润滑模型。利用微结构平缓摩擦系统低速区间Stribeck曲线，使系统具有正等效阻尼，实现抑制摩擦噪声。基于上述理论，优化微结构形状、尺寸及排列形式，获得微结构参数与系统摩擦学特性的作用机制，为其在水润滑领域的应用奠定理论基础。本项目旨在揭示微结构化超表面润滑机理，可望应用于水润滑摩擦副的减阻降噪，为改善其摩擦学性能和降低摩擦噪声提供理论依据和技术保障，并获得具有学术价值和工程应用价值的成果。

水润滑摩擦副在低速条件下剧烈的摩擦磨损会增加能耗、缩短寿命，并通过摩擦振动产生严重的噪声污染，因此其减阻降噪研究十分必要。通过摩擦表面织构设计对润滑介质流动和铺展进行引导，从而改善界面摩擦学行为，减小摩擦磨损，降低噪音，具有重要科学意义与工程价值。本项目从亲水织构制备方法入手，提出了覆油膜加工法，减小织构加工过程中毛刺和氧化物的生成和粘结, 提高了纳秒激光织构加工质量。通过激光对超疏水表面进行区域化加工，实现了从超疏水到超亲水表面调控。进而通过区域激光加工技术制备出具有微亲水沟槽结构的超疏水表面，水滴在该表面垂直的两个方向具有显著差异的滚动角，最大滚动角差值高达82°，从而实现了水滴滚动的定向引导。最后，本项目提出应用于水润滑接触区的“V”形亲水织构和应用于非接触区的“楔形”亲水织构，实现了水润滑摩擦副的减摩降噪，最大摩擦系数降低率达53.9 %，最大摩擦噪声降低率达21.7 %。本项目揭示了超疏水表面亲水织构对润滑水引导和铺展调控机理，可望应用于水润滑摩擦副的减阻降噪，为改善其摩擦学性能和降低摩擦噪声提供理论依据和技术保障。在项目的资助下，共发表学术论文8篇（SCI论文6篇），申请发明专利4项，获得陕西省高等学校科学技术奖一等奖1项，完成了项目任务书的论文、专利等目标。