流体支承可倾瓦滑动轴承油量平衡分析及数值计算

Analysis of Oil Balance and Numerical Simulation of Fluid Pivot Journal Bearing

关键词:  滑动轴承  流体支承  可倾瓦  计算流体动力学  供油量  舰艇

Key words:  Journal bearing  Fluid pivot  Tilting pad  CFD  Oil supply  Naval vessels

摘要:

流体支承可倾瓦滑动轴承具有良好的抗冲击性、高寿命和高转速，能够满足舰船对支承部件的需求，但其进油量仅为传统可倾瓦滑动轴承的1/2左右，为了确保安全稳定性，需要精确分析油量平衡关系。本文针对一直径为160mm的流体支承可倾瓦滑动轴承的动、静压油膜进行了三维数值模拟及分析，构建了包含动压层油膜、静压层油膜、进油孔、进油腔、动静压连接孔、静压油腔及瓦间间隙等细节的流体支承可倾瓦模型，采用包含空化模型的三维粘性N-S方程对油膜流场进行了计算，获取了荷载为8820N，转速为1000~8000r/min平衡状态下油量分布情况。计算结果表明，随着转速的增加，轴承的需油量线性增加，瓦块进口侧油腔的压力逐渐增加至高于供油压力0.15MPa，仅有瓦块前缘进口进油不能满足充分润滑需求。为了满足油量平衡需求，联合油量平衡和能量损失模型预测了不同瓦间基座开孔直径下的总进油量分布情况，在转速小于3000r/min时随着转速的增加总进油量逐渐减小，经过某一阀值之后随着转速增加进油量逐渐增加。试验测试结果表明，在开孔直径为2.3mm时，最小进油量为44.49L/min，与理论计算的43.24L/min相差2.4%，吻合较好。本文建立的油量平衡模型可以较好地预测该类轴承的油量平衡机制。

Abstract:

Fluid pivot journal bearing can meet the needs of special occasions such as high speed， long service life and excellent impact resistance in ships field. However， its oil intake is only about 1 / 2 of the traditional tilting pad journal bearing. In order to accurately analyze the oil balance relationship of fluid pivot journal bearing and ensure safety and stability， three-dimensional numerical simulation and analysis are carried out for the dynamic and static oil film of a fluid supported tilting pad journal bearing with a diameter of 160mm. Fluid pivot journal pad model including dynamic layer oil film， static layer oil film， inlet hole，inlet cavity， dynamic and static connection hole， static pressure oil cavity and inter-pad gap is constructed. Flow field of oil film is calculated by using three-dimensional viscous N-S equation including cavitation model， and oil flow distribution under balanced condition with load of 8820N and speed of 1000~8000r/min is obtained. The calculation results show that under the calculated load， with the increase of the speed， the oil demand of the bearing increases linearly， but the pressure at the end of the oil inlet cavity increases with the increase of the speed， the pressure of the oil chamber at the inlet side of the pad gradually increases to 0.15MPa， which is higher than the oil supply pressure， as a result， the oil inlet hole cannot provide enough oil when the speed increases. In order to satisfy the oil demand for oil balance， the combined flow balance and energy loss model predicted the total oil intake distribution under different opening diameters of the bearing shell. It is concluded that the total oil intake decreases with the increase of speed when the speed is less than 3000r/min and increases with the increase of speed after a certain threshold value. The test results show when the opening diameter is 2.3mm， the minimum oil intake is 44.49L/min， which is 2.4% different from the theoretical calculation of 43.24L/min， and the accuracy of the results is well verified. The oil balance model in this paper can better predict the oil balance mechanism of this kind of bearing.