稀薄效应对径向气体轴承承载性能的影响
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摘要
基于超薄气膜润滑理论,通过引入微尺度条件下气体稀薄效应流量因子,推导考虑稀薄效应的气体润滑轴承雷诺方程,并采用有限差分法对其进行离散求解,数值分析了不同偏心率、半径间隙以及转速对气膜压力分布、承载力的影响规律,并与未考虑稀薄效应的数值结果进行比较。结果表明:稀薄效应的存在并不会影响压力分布规律,其中气膜压力分布具有非线性,并沿着轴向呈抛物线状;最大压力及承载力随转速和偏心率的增大而增大,随着半径间隙的增大而减小;当考虑气体稀薄效应时,气膜各点压力水平及承载力相比于未考虑时有所下降;当半径间隙越小,偏心率越大时,气体稀薄效应越显著,最大压力及承载力的变化幅度也越明显。
Based on the theory of the molecular gas-film lubrication,the Reynolds equation of the gas bearing was deduced through introducing flow factor of the rarefaction effect under the micro-scale condition,and was dissociated by using the finite difference method. The influence of different eccentricity,radius gap and speed on the pressure distribution and bearing capacity was numerically analyzed and compared with the numerical results without the rarefaction effect. The results show that the presence of the rarefaction effect does not affect the pressure distribution,in which the pressure distribution is non-linear and parabolic along the axial direction. The maximum pressure and bearing capacity increase with the increase of speed and eccentricity,and decrease with the increase of radius gap. When considering the rarefaction effect,the pressure and bearing capacity are lower. When the radius gap is smaller and the eccentricity is larger,the rarefaction effect is more significant,and the change of maximum pressure and bearing capacity is more obvious.
Based on the theory of the molecular gas-film lubrication,the Reynolds equation of the gas bearing was deduced through introducing flow factor of the rarefaction effect under the micro-scale condition,and was dissociated by using the finite difference method. The influence of different eccentricity,radius gap and speed on the pressure distribution and bearing capacity was numerically analyzed and compared with the numerical results without the rarefaction effect. The results show that the presence of the rarefaction effect does not affect the pressure distribution,in which the pressure distribution is non-linear and parabolic along the axial direction. The maximum pressure and bearing capacity increase with the increase of speed and eccentricity,and decrease with the increase of radius gap. When considering the rarefaction effect,the pressure and bearing capacity are lower. When the radius gap is smaller and the eccentricity is larger,the rarefaction effect is more significant,and the change of maximum pressure and bearing capacity is more obvious.
引文
[1]李健,李青,李晓明.静压气体轴承承载特性的数值计算研究[J].润滑与密封,2016,41(12):1-5.
[2]闫佳佳,刘占生,张广辉,等.考虑稀薄气体效应的止推箔片轴承静特性分析[J].航空动力学报,2016,31(6):1521-1529.
[3]Wang M,Lan X,Li Z.Analyses of gas flows in micro-and nanochannels[J].International Journal of Heat&Mass Transfer,2008,51(13-14):3630-3641.
[4]Lee Y B,Kwak H D,Kim C H,et al.Numerical prediction of slip flow effect on gas-lubricated journal bearings for MEMS/MST-based microrotating machinery[J].Tribology International,2005,38(2):89-96.
[5]Zhang W M,Zhou J B,Meng G.Performance and stability analysis of gas-lubricated journal bearings in MEMS[J].Tribology International,2011,44(7-8):887-897.
[6]张小青,王晓力,石文天,等.Bow型硅微加工缺陷对动压气体轴承动态特性的影响[J].润滑与密封,2015(12):29-36.
[7]陈东菊,周帅,杨智,等.稀薄效应对空气静压止推轴承性能影响[J].四川大学学报:工程科学版,2016,48(1):194-199.
[8]Shi B J,Yang T Y.Simplified model of Reynolds equation with linearized flow rate for ultra-thin gas film lubrication in hard disk drives[J].Microsystem Technologies,2010,16(10):1727-1734.
[9]张小青,司丽娜,刘玉德.硅基超短微空气径向轴承的非线性动态特性研究[J].轴承,2016(2):27-32.
[10]王学敏,杜建军,李姗姗.基于有限差分法对不同润滑介质下静压气体轴颈轴承性能研究[J].机械工程学报,2012,48(3):121-127.
[2]闫佳佳,刘占生,张广辉,等.考虑稀薄气体效应的止推箔片轴承静特性分析[J].航空动力学报,2016,31(6):1521-1529.
[3]Wang M,Lan X,Li Z.Analyses of gas flows in micro-and nanochannels[J].International Journal of Heat&Mass Transfer,2008,51(13-14):3630-3641.
[4]Lee Y B,Kwak H D,Kim C H,et al.Numerical prediction of slip flow effect on gas-lubricated journal bearings for MEMS/MST-based microrotating machinery[J].Tribology International,2005,38(2):89-96.
[5]Zhang W M,Zhou J B,Meng G.Performance and stability analysis of gas-lubricated journal bearings in MEMS[J].Tribology International,2011,44(7-8):887-897.
[6]张小青,王晓力,石文天,等.Bow型硅微加工缺陷对动压气体轴承动态特性的影响[J].润滑与密封,2015(12):29-36.
[7]陈东菊,周帅,杨智,等.稀薄效应对空气静压止推轴承性能影响[J].四川大学学报:工程科学版,2016,48(1):194-199.
[8]Shi B J,Yang T Y.Simplified model of Reynolds equation with linearized flow rate for ultra-thin gas film lubrication in hard disk drives[J].Microsystem Technologies,2010,16(10):1727-1734.
[9]张小青,司丽娜,刘玉德.硅基超短微空气径向轴承的非线性动态特性研究[J].轴承,2016(2):27-32.
[10]王学敏,杜建军,李姗姗.基于有限差分法对不同润滑介质下静压气体轴颈轴承性能研究[J].机械工程学报,2012,48(3):121-127.