微间隙下狭缝节流动静压混合气体轴承-转子系统的特性研究

Aerostatic bearings have been successfully used in high-precision machine tools, high-speed rotors and so on because of their advantages such as high-speed, high-precision, and small power dissipation. And the slot-restricted aerostatic bearings has the advantage of continuous, uniform pressure distribution. Along with the industry's rapid development, the requirement of the bearing performance increases. Reducing the gas film clearance is able to improve the static and dynamic characteristics of the gas bearings because the dynamic effect and the pressure distribution will be improved. However, the decrease of gas film clearance，it will exceed the traditional gas lubrication theory and reduce the calculation accuracy. The slot-restricted hybrid gas bearing under micro gas film clearance is taken as the study subject in this topic. In order to calculate the flow field accurately, the calculation model is studied and built, in which the influence of turbulent flow, dynamic effect, and the slip effect will be fully considered. The influence of the structure of slot, the structure of dynamic groove, the gas film clearance on the system will be studied under micro gas film clearance and high-speed working condition, and the influence mechanism and law will be obtained. To make full use of dynamic effect and improve the system's performance, one new type of slot-restricted hybrid gas bearing-rotor will be proposed, and the design criteria of which will be preliminary studied.

静压气体轴承具有运转速度高、精度高、能耗低等优点，在超精密机床、高速转子等设备上具有良好的适用性，其中狭缝节流静压气体轴承具有压力分布连续、均匀等优点。伴随工业的飞速发展，对轴承性能的要求不断提高。减小气膜间隙，动压效应增强，压力分布提高，轴承的动静态特性提高；然而气膜间隙的减小，局部流场将突破传统的气体润滑理论，计算精度降低。本课题以微气膜间隙下狭缝节流动静压混合气体轴承-转子系统为研究对象，研究建立微气膜间隙下充分考虑局部湍流、局部滑移流动及动压效应等影响的流场计算模型，实现轴承流场的精确计算；研究微间隙高速状态下狭缝结构、动压槽结构、气膜厚度等对系统特性的影响，揭示其影响机理及规律；以充分利用高速状态下的动压效应和提高系统特性为目标，提出一种新型狭缝节流动静压混合气体轴承-转子结构，并初步探讨其设计准则。

气体轴承具有转速度高、精度高、能耗低等优点，在航空航天技术、微电子技术、高端制造等领域具有广泛的应用价值，且对其性能的要求不断提高。其中狭缝节流静压气体轴承具有压力分布连续、均匀等优点；同时减小气膜间隙，动压效应增强，压力分布提高，轴承的动静态特性提高；然而气膜间隙的减小，局部流场将突破传统的气体润滑理论，计算精度降低。本项目以微间隙下狭缝节流动静压混合气体轴承-转子系统为研究对象，采用CFD软件建立了充分考虑滑移流动、动压效应等影响的三维流场计算模型，揭示了微间隙下滑移效应对轴承特性的影响规律；同时采用MATLAB软件基于有限差分法完成了对轴承-转子系统动态特性的求解；研究了狭缝类型、狭缝结构、动压槽结构、转速、轴承长径比等对轴承-转子系统特性的影响规律；提出了一种新型狭缝节流动静压混合气体轴承转子结构，并采用灰色理论和正交试验法对其进行优化设计，初步提出其设计准则；搭建实验台，对轴承的特性进行测试分析，并验证了理论分析的正确性及适应性。本项目的研究成果为微间隙下高精度气体轴承-转子系统的设计研究提供了一定的理论和实验依据。