快堆钠泵动静压导轴承润滑特性分析

Lubrication Characteristics of Hybrid Bearing in Sodium-cooled Fast Reactor

快堆钠泵导轴承的润滑介质、工作原理以及润滑状态与传统滑动轴承均有显著不同,目前关于该类轴承的研究鲜有报道。为对钠泵导轴承设计和运行维护提供理论支撑,为以某快堆钠泵工程样机的内反馈轴承为研究对象,考虑紊流和动静压耦合关系等因素,建立了其润滑分析模型,采用自编有限元程序求解得到了典型工况下轴承的动静特性,分析了工况参数与关键结构参数对其润滑特性的影响。结果发现:钠液黏度低、密度大,紊流对液膜的润滑性能具有重要影响;当偏心率小于0.6时,主要由静压起主导作用,当偏心率大于0.6时,动压作用不可忽略,非线性效应增强;间隙增加最小油膜厚度线性增加、流量显著加大、稳定性下降;入口扬程增加,静压作用增强,流量增加,稳定性增强,典型工况下入口扬程应大于50 m才能保证轴承的高可靠性。

The lubricant, working principle and lubrication regime of the guide bearing of the main pump in the sodium-cooled fast reactor are significantly different from conventional film bearing. The lubrication analysis model of the hybrid bearing is established with considering turbulence and pressure-coupling effects. The dynamic and static characteristics of the bearing are obtained by using self-coded finite element code. The working conditions and key geometrical parameters on its lubrication characteristics are systematically analyzed. It is found that the viscosity of sodium liquid is very low and the density is high, so the turbulence has significant effects on the lubrication performance. Moreover, when the eccentricity ratio is less than 0.6, hydrostatic effect plays a leading role, whereas the hydrodynamic effect cannot be ignored when the eccentricity ratio is greater than 0.6. Furthermore, when the bearing clearance increases, the minimum film thickness and the flow rate increases, while the stability decreases. When the inlet head increase, the hydrostatic effect is enhanced, and both the flowrate and the stability increase. The inlet head should be more than 50 meters to ensure the high reliability.