Design and Experimental Research of the Oil-free Turbocharger

doi:10.3901/JME.2018.19.129

Abstract

Abstract: An oil-free turbocharger (TC) supported by the gas foil bearings (GFBs) is designed and an comprehensive experimental studies on the designed oil-free TC is presented.The detail design process of the oil-free TC is described. The nominal clearance is evaluated through the static load test. The structure stiffness of the GFB is predicted based on the Link-Spring model. The bearing dynamic stiffness and damping coefficients are predicted using the perturbation method by coupling the Link-Spring model and the Reynolds' equation. The linear rotordynamic analysis shows the first two rigid mode critical speeds are lower than the lift-off speed of the GFB. Moreover, the oil-free TC operating speed is much smaller than the first bending mode critical speed, which demonstrate the designed rotor have enough safety margin. The oil-free TC test rig is built based on the theoretical analysis of the design. The speed-up and coast-down results show that significant subsynchronous motion is occurred at 20 kr/min~60 kr/min, while the subsynchronous amplitude decreases significantly when the operating speed increases to 68 kr/min. The orbit and FFT analysis results when the rotor operates at 68 kr/min show the synchronous motion dominates the vibrations, which demonstrate the oil-free TC can operate stably at 68 kr/min. Meanwhile, the real-time temperature of the thrust GFB and journal GFB is recorded when the rotor operated at 68 kr/min. The temperature of the thrust GFB and journal GFB almost keep constant at 52℃ and 32℃, respectively, which demonstrate the stability of the designed rotor-bearing system.

Key words: gas foil bearing, oil-free turbocharger, rotor dynamic

CLC Number:

TH133

LIU Wanhui, LÜ Peng, YU Rui, FENG Kai. Design and Experimental Research of the Oil-free Turbocharger[J]. Journal of Mechanical Engineering, 2018, 54(19): 129-136.

References

[1] 邓建. 箔片空气轴承的新近技术突破与应用进展[J].轴承,2004(8):41-44. DENG Jian.Recent advances in foil air bearing and its application[J].Bearing,2004(8):41-44.
[2] 刘占生.波箔型动压气体径向轴承的应用与研究进展[J].轴承,2008(1):39-43. LIU Zhansheng. Application and research progress of foil type dynamic pressure gas radial bearings[J].Bearing,2008(1):39-43.
[3] HESHMAT C A,HESHMAT H,VALCO M J,et al. Foil bearings makes oil-free turbocharger possible[J]. American Society of Mechanical Engineers,2005:113-114.
[4] LEE Y B,PARK D J,KIM T H,et al. Development and performance measurement of oil-free turbocharger supported on gas foil bearings[J].Journal of Engineering for Gas Turbines and Power,2012,134(3):032506.
[5] 黄宜森.涡轮发电机轴向箔片气动轴承的建模与数值分析研究[D].哈尔滨:哈尔滨工业大学,2009. HUANG Yisen.Research on modeling and numerical analysis of axial foil pneumatic bearing of turbogenerator[D].Harbin:Harbin Institute of Technology,2009.
[6] 刘占生. 箔片预变形对箔片气体径向轴承静特性影响分析[J].航空动力学报,2009,24(1):181-188. LIU Zhansheng.Analysis of foil pre-deformation on static characteristics of foil radial bearing[J].Journal of Aerospace Power,2009,24(1):181-188.
[7] 马永利.弹性波箔型动压气体径向轴承的特性分析和实验研究[D].南京:南京航空航天大学,2012. MA Yongli.Characteristic analysis and experimental study of elastic wave foil type dynamic pressure gas radial bearing[D].Nanjing:Nanjing University of Aeronautics and Astronautics,2012.
[8] 郑越青.箔片轴承固体润滑用类金刚石薄膜的设计,制备和性能研究[D].绵阳:中国工程物理研究院,2010. ZHENG Yueqin.Design, fabrication and properties of diamond-like carbon films for solid lubrication of foil bearings[D].Mianyang:China Academy of Engineering Physics,2010.
[9] HOU Y,ZHU Z,CHEN C,Comparative test on two kinds of new compliant foil bearing for small cryogenic turbo-expander[J].Cryogenics,2004. 44(1):69-72.
[10] XIONG L Y,WU G,CHEN C Z,et al. A feasibility study on the use of new gas foil bearings in cryogenic turboexpander[J]. Advances in Cryogenic Engineering,1998:661-665.
[11] XIONG L Y,WU G,HOU Y,et al. Development of aerodynamic foil journal bearings for a high speed cryogenic turboexpander[J].Cryogenics,1997,37(4):221-230.
[12] 邓为民.涡轮冷却器中空气动压轴承的应用及其改进[J].装备制造技术,2014(4):140-142. DENG Weimin.Application and improvement of air dynamic bearing in turbo cooler[J]. Equipment Manufacturing Technology,2014(4):140-142.
[13] DELLACORT C,ZALDANA A R,RADIL K C. A systems approach to the solid lubrication of foil air bearings for oil-free turbomachinery[J].Journal of Tribology,2004,126(1):200-207.
[14] HESHMAT H. Advancements in the performance of aerodynamic foil journal bearings:high speed and load capability[J]. Journal of Tribology,1994,116(2):287-294.
[15] KIM T H,ANDRES L S. Effects of a mechanical preload on the dynamic force response of gas foil bearings:measurements and model predictions[J]. Tribology Transactions,2009,52(4):569-580.
[16] DELLACORTE C,WOOD J. High temperature solid lubricant materials for heavy duty and advanced heat engines[R].Washington:NASA Report,1994.
[17] LEE Y B,KWON S B,KIM T H.Feasibility study of an oil-free turbocharger supported on gas foil bearings via on-road tests of a two-liter class diesel vehicle[J].Journal of Engineering for Gas Turbines and Power,2013,135(5):052701.
[18] FENG K,KANEKO S. Analytical model of bump-type foil bearings using a link-spring structure and a finite-element shell model[J].Journal of Tribology,2010,132(2):021706.
[19] RADIL K,HOWARD S,DYKAS B. The role of radial clearance on the performance of foil air bearings[J]. Tribology Transactions,2002,45(4):485-490.
[20] FENG K,KANEKO S. Calculation of dynamic coefficients for multiwound foil bearings[J].Journal of System Design and Dynamics,2009,3(5):841-852.
[21] 虞烈. 弹性箔片轴承的气弹润滑解[J].西安交通大学学报,2004,38(3):327-330. YU Lie. Aeroelastic lubrication solution of elastic foil bearing[J]. Journal of Xi'an Jiaotong University,2004,38(3):327-330.
[22] 虞烈.弹性箔片空气动压轴承的完全气弹润滑解[J]. 中国科学,2005,35(7):746-760. YU Lie.Complete aeroelastic lubrication solution of elastic foil hydrodynamic bearings[J].China Science Journal,2005,35(7):746-760.
[23] SIM K,YONG B,KIM T H. Rotordynamic performance of shimmed gas foil bearings for oil-free turbochargers[J]. Journal of Tribology,2012,134(3):031102.