高速轴承腔体内宽域流动-传热势容耗散机理与喷射润滑设计

Lubrication performance is the primary factor restricting the "high DN" index of rolling bearings. Jet lubrication, owe to its high pressure oil supply and efficient convection heat transfer characteristics, is the preferred lubrication method for high-speed bearings. In view of the poor lubrication caused by high shear air curtain during oil-air jetting process at high rotating speed, this project put forward the idea of utilizing the “potential difference and internal power” to drive the oil flow in the raceway, based on the way that the internal flow power can change the flow field. Thus the problem of oil layer attenuation in jet lubrication is solved effectively and the high-speed performance of rolling bearings is improved. In order to accurately characterize the thermal field gradient and flow field potential difference in the cross-scale flow field of high-speed bearing cavity, a transient thermal field monitoring technique based on the light-heat effect of quantum dots was proposed, and a wide-area flow field morphology modeling method based on interface tracking was constructed. On the basis of this, from the perspective of dissipation of flow and heat transfer potentials, the thermal-force-flow multi-gradient potential difference and energy dissipation mechanisms in high-speed bearing chambers are revealed. Based on the potential dissipation and field cooperation mechanism, the flow field design in the high-speed bearing cavity is carried out with the help of raceway texture and other auxiliary methods. Then the aim that oil film on the raceway actively driving by the “potential difference and internal power” is achieved. The research of this project will provide a new theoretical basis for the jet lubrication design of rolling bearings in ultra-high speed environments.

润滑性能是制约滚动轴承“高DN值”指标的首要因素。喷射润滑因其高压供油与高效对流传热特点，成为高速轴承的首选润滑方式。针对喷射过程中剪切气流高压气帘导致高速下润滑不足的问题，本项目基于流体内能改变流场的思想，借助流动-传热过程中的热梯度、流动势等“势差与内能”驱动滚道油层流动，有效解决喷射润滑中的油层衰减与供油不足问题，提升滚动轴承的高速性能。为了精确表征高速轴承腔体跨尺度流域内的热场梯度与流场势差，提出基于量子光-热效应的瞬态热场监测技术，构建基于界面追踪的宽域流场形态建模方法。在此基础上从流动与传热势容耗散角度出发，揭示高速轴承腔体内热-力-流多梯度势差与能量耗散机理。基于耗散极值与多势场协同机制开展滚道织构等辅助方式下的高速轴承腔体内流场设计，实现基于“势差与内能主动驱动”的滚道-接触区入口供油油层补充，为超高速环境下滚动轴承喷射润滑设计提供新的理论依据。

滚动轴承被视为机器的“关节”，影响着国民经济及国防领域超过万亿的重大装备运行可靠性。我国精密机床用高性能轴承和国外还存在较大差距，以轴承高速性能为例，我国轴承高速DN值在2.5×106mm∙r/min，而国外轴承DN值早已超过3.5×106mm∙r/min。NSK研究表明，决定轴承高速性能的核心是润滑和散热技术。本项目瞄准轴承高速运行中的内部热状态无法测试、轴承润滑调控依赖经验的工程难题，提炼了轴承腔体内旋转组件温度场与温差梯度精准建模、轴承腔体内热场与流场协同设计两个基础科学问题，布局了基于全组件热态数据的高速轴承温差梯度与势容函数构建、基于油气界面追踪的轴承腔内跨尺度流场建模分析、基于势容耗散的高速轴承腔内流场-热场协同机制以及高速轴承“主动”润滑设计四个研究内容。通过项目研究，掌握了轴承润滑与热调控的核心技术。在轴承内部温度监测方面，项目研究形成了独创的基于量子光-热效应的高速轴承旋转组件温度实时监测技术，实现了在不破坏轴承结构、不影响轴承运动的前提下在线测试轴承旋转组件温度。在轴承润滑设计方面，项目研究证实了高速下的二次气帘效应是制约轴承润滑效率的关键，并提出了滚动轴承高速乏油工况下的沟槽引导润滑增效技术，显著提升了高速轴承的润滑效率。项目形成的滚动轴承旋转组件温度测试技术装置应用于洛阳轴承研究所、国际知名的SKF轴承公司等。项目形成的润滑可视化分析方法应用于航发哈轴、北京金风等重大装备轴承润滑分析中。项目形成的轴承润滑喷嘴设计及润滑增效方法有力支撑了我国DN值4.0×106mm∙r/min高速轴承的自主研发制造。.项目成果发表论文16篇，其中SCI论文7篇，撰写《滚动轴承热设计方法》专著1部；培养研究生12名，获得国家奖学金3次，轴承企业专项奖学金8次；项目负责人获得国家自然科学基金优秀青年科学基金资助；项目团队在SCI学术期刊Lubricants上组织了《Advances in Bearing Lubrication and Thermal Sciences》学术专题，征集研究论文17篇；项目负责人作为主编出版了轴承润滑与热学术专题论文集，下载量超过1万次。