纳米粒子气膜承载能力研究

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Study on Load Capacity of Nanoparticles-laden Gas FilmDIAO Dongfeng YANG Zhiru FAN Hongyan ' FAN Xue (1.School ofMechanical Engineering，Xial Jiaotong University，Xiai1 710049；2.Key Laboratory of Education M inistry for M odem Design and Rotor-Bearing System，Xian Jiaotong University，Xian 7 1 0049)Abstract：Nanoparticles of 30 lm in diameter are added into a gas thrust bearing，in which the film thickness is 45 m.Then，ananopatticles-laden gas film with diferent nanopatticles volume fraction is formed.The enhancement efect of nanoparticles on gasfilm load capacity is studied with a self-developed experimental appatatus and the mechanism of this phenomenon is discussed.Theload capacity and film pressure before and after adding nanopatticles，which varies with the film thickness，ate measured.Thevariation tendency of load capacity with nanopattieles volum e fraction is derived.It is found that the load capacity increases with theincrease of nanopattieles volum e fraction.When the nanopatticles volum e fraction is about O.04%，the increment of load capacityreaches about 20%.Th en，the increment of load capacity decreases gradually.For understanding the variation and the mechanism ofload capacity enhancement efects by nanoparticles，fluid mechanics equations that considered gas and nanopatticles interaction ateemployed to calculate the film pressure distributions.By comparing the numerical and the experimental results，the variations of loadcapacity with nanoparticles volum e fraction are verified.Th e study proves that nanoparticles has an enhancement efect on gas filmload capacity for the first time.Besides，the finding provides an engineering guidance for the design of novel nanoparticles-laden gasfilm rotor-beating system。

Key words：Nanopatticles Volum e fraction Nanopatticles-laden gas film Load capacity Pressure0 前言在高速气体轴承转子系统中，气膜抵抗突变冲·国家自然科学基金资助项N(51175405)。20121105收到初稿，20130228收到修改稿击载荷的能力较低，易导致轴承和转子表面产生严重的冲击碰撞和滑动接触损伤。为了克服气体轴承的这-弱点，需要提高气膜承载能力以及气膜对轴承表面的保护作用。很多学者进行了大量相关的研究工作，但是这两方面工作都是单独进行的，目前还没有可以同时实现这两个目标的方法。

J2013年 7月 刁东风等：纳米粒子气膜承载能力研究 57载能力的作用。因此，纳米粒子团聚不会改变纳米粒子可以增强气膜承载能力的结论。虽然在试验中限制了较大的气膜膜厚和较小的纳米粒子体积分数以及假定了纳米粒子在气膜内均匀分布。但是，本研究提出的-种纳米粒子作为添加剂的新的应用方式为纳米粒子新型轴承的设计提供了参考。

6 结论本文利用 自行研制的推力轴承纳米粒子气膜试验平台，研究了纳米粒子气膜的承载能力。通过大量的试验与理论计算得出如下结论。加入纳米粒子可以明显增大气膜承载能力，其原因是纳米粒子混合气体的黏度较纯气体增高所致。纳米粒子气膜的承载能力随着纳米粒子体积分数的增加而逐渐增加，纳米粒子体积分数约为 0.04%时，承载能力的增加幅度最大约为20%，纳米粒子体积分数进-步增加时承载能力增加幅度开始减校通过对不同纳米粒子体积分数下的大量试验数据的拟合，得出气膜承载能力与纳米粒子体积分数的关系。研究结论对纳米粒子气膜润滑原理的认识及新型转子轴承系统的设计具有指导意义。