基于支承系统随机共振的滑动轴承减摩机理研究

For the issue of friction losses of hydrodynamic lubricated journal bearings, the project develops an approach for the active friction reduction through random mechanical resonances of the supporting system due to the coupling of the micro surface profile and the fluid film. Firstly, the formation mechanism of the hydrodynamic lubricated viscous friction is studied as well as the relation with the working condition. The quantitative relation of the vibration and its produced waves and the fluid parameters, such as velocity field, pressure field, density field, etc. of the lubricant is established. The mechanism of viscosity reduction and resistance reduction for the hydrodynamic lubrication is revealed. Then, the random excitation of the supporting system due to the coupling of the micro surface profile and the fluid film of the journal bearing is investigated. The relation of the micro surface profile, working condition and the random mechanical resonance of the supporting system is clarified. Finally, the model of friction reduction based on the random mechanical resonance is developed, the sensitivity matrix of the friction loss to the structural parameters of the bearing is acquired, which offers the theoretical foundation for the structural optimisation design of the bearing aimed at the friction reduction. Through the research of the project, the mechanism of vibration friction reduction will be clarified and the issue of the excitation source will also be addressed, which will overcome the main difficulties that restrict the popularisation of the technique of vibration friction reduction in the field of hydrodynamic lubrication. It has a great significance for the reduction of friction losses in the rotating machinery and the efficiency promotion of energy utilisation.

本项目针对流体润滑滑动轴承的摩擦功率损耗问题，提出一种利用摩擦副表面微观形貌与流体油膜的相互作用，激励起支承系统的随机共振来实现主动减摩的方法。首先，探索流体润滑粘滞摩擦阻力的形成机理及其随运行工况的变化规律。建立摩擦副振动及所产生的声波与润滑介质的速度场、压力场、密度场等流体参数之间的量化关系，揭示其对流体润滑的降粘、降阻机理。然后，探索滑动轴承摩擦副表面微观形貌与流体油膜的流固耦合作用对支承系统随机激励特性的影响，明确表面形貌参数、运行工况与支承系统随机共振之间的联系。最后，建立基于随机共振的减摩模型，获取摩擦功耗对轴瓦结构参数的灵敏度矩阵，为以主动减摩为目标的轴瓦结构优化设计提供理论依据。通过本项目的研究，将在阐明振动对流体润滑摩擦副减摩机理的同时，解决激振源的问题，攻克目前制约振动减摩技术在流体润滑领域推广的主要难点。对减少旋转机械的摩擦功率损失，提高能源利用效率，具有重要的意义。

本项目针对流体润滑滑动轴承的摩擦功率损耗问题，研究了一种利用摩擦副表面微观形貌与流体油膜的相互作用，激励起支承系统的随机共振来实现主动减摩的方法。首先对计入粗糙表面影响的层流润滑摩擦副声振机理进行了研究，在考虑非高斯表面上微凸体扰动的情况下，建立了动态流固耦合模型，分析了流体动压润滑区域内产生的声发射波特性；采用摄动法求解了由微观流固耦合引起的随机压力扰动的解析表达式，研究了在动压润滑条件下轴颈轴承高频共振的激励机理。然后建立了滑动轴承-转子系统的摩擦动力学模型，利用粒子群优化算法对有限元模型进行了修正；利用增强型卡尔曼滤波算法，实现了从单一位置的测量位移中准确识别滑动轴承的动态特性参数。最后，分析了动静织构对滑动轴承摩擦功耗的影响，讨论了表面织构对润滑性能的影响；利用遗传算法寻找最优减摩参数，分析了织构的结构参数与分布参数对摩擦功耗的影响规律；对滑动轴承的超声空化现象进行了研究，探索了空化泡在润滑油中的发展规律，获取了气泡对滑动轴承摩擦功耗的影响规律。. 通过本项目的研究，对层流润滑粘滞摩擦阻力的形成机理及其随运行工况的变化规律有了比较客观的认识，掌握了滑动轴承摩擦副表面微观形貌与流体油膜的耦合作用对支承系统的随机激励特性的影响，获取了表面微观形貌参数、运行工况与支承系统随机共振之间的联系。建立了摩擦副振动与润滑介质的速度场、压力场、密度场等流体参数之间的量化关系，揭示了其对流体润滑的降粘、降阻机理。项目的研究成果为以主动减摩为目标的轴瓦结构优化设计提供了理论依据。. 项目资助发表学术论文21篇，其中被SCI检索18篇。申请并授权实用新型专利2项。培养博士研究生2名，硕士研究生2名，其中1名已取得硕士学位，1名转为硕博连读。项目投入经费24万元，支出14.41万元，各项支出基本与预算相符。剩余经费9.59万元，其中1.8万元已用于订购加速度传感器和位移传感器若干，剩余经费计划用于本项目研究的后续支出。