高原活塞裙部表面楔形三角微织构的空化耦合惯性效应减摩特性研究

针对发动机摩擦磨损的严重负面效应、活塞裙部不同位置与缸套接触运动方向相异的特点及高原地区空化发生条件的特殊性，本研究以柴油发动机活塞裙部为研究对象，设计制备旋转圆环空化设备，结合有限元分析研究微织构内润滑油空化流场的压力、空泡分布和空化演化过程。在高原下进行两端非对称(楔形三角)微织构摩擦学性能模拟实验，获取最佳织构几何参数。在活塞裙部制备方向相反微织构，进行高原台架试验，采用Schnerr-Sauer方法建立流体润滑空化边界条件，数值求解N-S方程得到高原两端非对称表面微织构内油膜的压力分布和承载能力，综合分析微织构的摩擦学作用，建立基于空化耦合惯性效应的高原柴油发动机活塞裙部两端非对称表面微织构减摩抗磨理论模型，提出微织构设计的要求和准则。为提高柴油发动机的可靠性、使用寿命及能源效率提供理论依据和技术支持。本研究对自然通风高原农业柴油机及柴油发电机组的优化应用具有较为重要的意义。

This study is aimed at the serious negative effects of engine friction and wear, the opposite motion direction characteristics of piston skirt with cylinder liner in their contact process, and the particularity of plateau cavitation conditions. This study taking the piston skirt of diesel engines as the research object. The rotating ring cavitation device will be designed and prepared. The pressure, cavitation and cavitation development process of the cavitation flow in the micro texture will be studied by the finite element analysis. The simulation experiments on the tribological properties of the asymmetric (wedge triangle) micro texture will be carried out at the plateau, and the optimum geometric parameters of the surface texture will be obtained. According to the optimum parameters, the opposite direction micro texture will be prepared on the piston skirt of diesel engine, and the plateau engine bench test will be carried out. The boundary condition of fluid lubrication cavitation will be established by Schnerr-Sauer method. The N-s equation will be solved numerically, and the pressure distribution and carrying capacity of the lubricating film inside the asymmetric surface of two ends at high altitude will be obtained. A friction reduction and anti-wear theoretical model of surface texture of diesel engines piston skirt and the requirements and criteria for the design of micro texture will be established based on the cavitation coupling inertia effect and the comprehensive analysis of the tribological effect of microtexture. The achievement of this research can provide the theoretical basis and technical support for solving the reliability, service life and energy efficiency of this sort diesel engines in the plateau. This study is of great significance for optimizing applications of high altitude natural ventilation agricultural diesel engine and diesel generator set.