| Driven by high temperature and high pressure exhaust gas from the engine, the rotor of the turbocharger always works at extremely high speed which can easily reach200krpm, the traditional single oil film bearings such as cylindrical bearing,ball bearing,are often difficult to satisfy the extreme conditions. Thanks to the application of the full floating bearing, it can improve not only the power consumption but also the stability of the rotor operation. However, it can also bring more complex dynamic phenomena because of its double oil films. The main works of this paper are as follows:A double overhung flexible rotor dynamic model of turbocharger is established through the transfer matrix method in this paper. Modal analysis of the whole system is carried out via the linearized oil film force, the influence of the supporting point and supporting stiffness on nature mode of rotor are researched, and the complex mode of gyroscopic system is also studied at then. According to the characteristics of the oil instability under the high speed working conditions, the influence of double oil film of floating ring bearing nonlinear effect on the rotor of the turbocharger system is investigated through numerical method combined with Capone oil force model, which is compared to a large number of the predecessors’ experimental researches. The rotational speed rate of the floating ring relative to the working speed, characteristic FFT spectrum and oil film eccentricity ratio are described to explain the typical characteristics of oil film instability of the turbocharger rotor system in this article and the influence of imbalance, bearing clearances and lubricant viscosity are also investigated. The results found that the double oil films of floating ring bearing have a large different with the ordinary single oil film bearing at oil instability characteristics, and dynamic response of the floating ring bearing is more complex under different parameters. |
PDF Full Text Request