摘要
浮环轴承内外轴向长度结构参数会影响油膜压力分布与偏心率,产生显著分频振动而引发高速轻载涡轮增压器转子非线性振动故障。基于流体润滑理论和浮环力矩平衡方程,推导了含浮环轴承的涡轮增压器转子系统动力学方程,揭示浮环轴承轴向长度与转子系统振动响应之间的关系。以某型汽油机用涡轮增压器转子系统为例,分析浮环内、外轴向长度对轴承油膜压力、偏心率等动力特性的影响,构建转子系统动力学有限元模型,通过三维振动瀑布图研究不同浮环轴向长度下转子系统频域瞬态振动响应,结果表明:浮环内轴向长度从2.6增加到4.6 mm,导致浮环转速升高,最大内油膜压力减小,轴颈偏心率降低,分频幅值增加且出现分频的轴颈转速由142 kr/min降至76 kr/min,更易产生明显的非线性涡动现象;浮环外轴向长度从3.6增加到6.15mm,使浮环转速降低,最大外油膜压力变小,浮环偏心率及轴颈相对浮环的偏心率减小,低转速下分频幅值减少且出现分频的轴颈转速由10 kr/min升至22 kr/min,可抑制转子系统过早发生非线性涡动,为浮环轴承结构参数设计与试验提供理论支撑。
The floating ring bearing axial length has an important effect on the distribution of oil film pressure and the eccentricity ratios,which leads to obvious sub-frequency vibration and nonlinear failure for the high-speed and light-loaded turbocharger rotor.Based on fluid lubrication theory and balance equation of floating ring moment,the dynamic equation of turbocharger rotor system with floating ring bearing is derived,and the relationship between floating ring bearing axial length and the vibration response of rotor system is revealed.Taking the turbocharger rotor system for a gasoline engine as an example,the influence of inner and outer axial lengths on the dynamic characteristics of the bearing oil film pressure and eccentricity ratios is analyzed,and the dynamic finite element model of the rotor system is constructed,the transient vibration response in frequency domain of rotor system with different floating ring axial lengths is studied by means of three-dimensional vibration waterfall.It shows that the floating ring inner axial length is increased from 2.6 to 4.6 mm,the floating ring rotation speed is increased,the maximum internal oil film pressure and the journal eccentricity ratios are decreased,the frequency division amplitude is increased,and the shaft speed of emerging sub-frequency is decreased from 142 kr/min to 76 kr/min.This also means that it is easier to generate obvious nonlinear whirling.When outer axial length increased from 3.6 to 6.15 mm,the floating ring speed and maximum outer oil film pressure are decreased respectively,the eccentricity ratios of the floating ring and the shaft neck relative to the floating ring are decreased,the sub-frequency amplitude is decreased at low speed,and the shaft speed of emerging frequency division is increased from 10 kr/min to 22 kr/min,which can restrain the premature nonlinear whirl of the rotor system.The results can provide theoretical support for structural parameters design and experiment of floating ring bearing.
作者
宾光富
黄源
钟新利
杨峰
BIN Guangfu;HUANG Yuan;ZHONG Xinli;YANG Feng(College of Mechanical Engineering,Hunan University of Science and Technology,Xiangtan 411201;VOFON Turbo Systems(Ningbo)Co.,Ltd.,Ningbo 315336)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2019年第23期173-181,共9页
Journal of Mechanical Engineering
基金
国家自然科学基金(51575176,11672106,51775030)
湖南省自然科学基金(2019JJ40084)资助项目
关键词
浮环轴向长度
涡轮增压器转子
动力特性
频域瞬态响应分析
分频振动
floating ring axial length
turbocharger rotor
dynamic characteristics
transient response analysis in frequency domain
sub-fiequency vibration
