摘要
箔片气体轴承以无油润滑、高转速、低摩擦功耗以及良好的减振性能等优点,广泛应用于燃料电池空压机和飞机换气系统等领域。在燃料电池空压机实际运行中,转子不仅受到空压机的气动载荷,还需要以不同的工作转速来匹配相应的负载,转子系统在加速变负载工况下表现出复杂的瞬态动力学响应,不匹配的加速度可能导致加速过程振幅增大,进而影响转子系统的动态稳定性。针对上述问题,建立了加速变载工况下箔片气体轴承转子系统动力学模型,提出并开发了相应的数值算法,利用该模型和算法对转子系统加速变负载过渡过程的轴心轨迹等动态性能做出了合理的定量解释。搭建了箔片轴承转子系统的实验台,并开展了相应的实验验证研究。研究发现,随着转速的增加,转子涡动现象愈发明显,动态平衡稳定区域逐渐靠近轴承中心;转子在加速过渡过程中的涡动中心向恒定转速下的稳定位置移动,加速时间越长,涡动攀升过程越平稳,在加速过程的前半段时间,转子加速移动的距离大于后半段;燃料电池空压机气动载荷导致转子加速攀升过程不平滑,轴心位移与气动载荷变化一致,而气膜分力与气动载荷变化相反。实验测得的轴心运动轨迹振动幅值比理论计算值大,但运动趋势相近。
The foil gas bearings are widely used in fuel cell air compressors and aircraft ventilation systems due to their advantages of oil-free lubrication,high speed,low friction power consumption,and good vibration reduction performance.In the actual operation of fuel cell air compressors,the rotor is not only subjected to the aerodynamic load of the compressor,but also needs to match the corresponding load at different operating speeds.The rotor system exhibits complex transient response under accelerated variable load conditions.Mismatched acceleration may lead to an increase in amplitude during the acceleration process,thereby affecting the dynamic stability of the rotor system.In response to the above issues,a theoretical model of accelerated rotor dynamics of the foil gas dynamic pressure bearing rotor system is established.Corresponding numerical algorithms are proposed and developed.The model and algorithm are used to provide a reasonable quantitative explanation for the dynamic performance of the rotor system during the transition process of accelerating variable load,such as the axis trajectory.The results of research find that as the rotational speed increases,the phenomenon of rotor vortex becomes more pronounced,and the dynamic equilibrium stable region gradually approaches the center of the bearing;During the acceleration transition process,the vortex center of the rotor moves towards a stable position at a constant speed.The longer the acceleration time,the smoother the vortex climb process.In the first half of the acceleration process,the distance of the rotor moves is greater than in the second half;The aerodynamic load of the fuel cell air compressor causes an uneven acceleration and climb process of the rotor,and the axial displacement is consistent with the changes in aerodynamic load,while the gas film component is opposite to the changes in aerodynamic load.
作者
熊万里
汪剑
薛海南
陈振宇
薛建
XIONG Wanli;WANG Jian;XUE Hainan;CHEN Zhenyu;XUE Jian(National Engineering Research Center for High Efficiency Grinding,Hunan University,Changsha 410082;Guangzhou Haozhi Industrial Co.,Ltd.,Guangzhou 511356)
出处
《机械工程学报》
北大核心
2025年第23期75-86,共12页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(52075155)。
