Dynamic stability experiments of compliant foil thrust bearing with viscoelastic support

Chen

et al. 2016

JAMDSM

Self Cite

In the fluid film lubrication of high speed turbomachinery, bearing performance plays a significant role in the dynamics of the rotor-bearing system. In this paper, a novel foil thrust bearing using multi-decked protuberant foils as supporting structure is developed and tested. Experimental bearing test rig using gas-driven high speed turbo-expander is set up to evaluate static loading characteristics of the bearing. Static stiffness, friction torque, nominal bearing clearance and axial vibration amplitude are discussed in the transient processes. Static loading characteristic of the bearing is evaluated based on the relationship between displacement and loading force. Test results indicate that this simply configured thrust bearing has a good prospect in high speed hydrodynamic lubrication.

“…High speed gas-driven bearing test rig is built based on the test rig (Zhou, et al, 2009). The process diagram of the test rig is shown in Fig.…”

Section: Gas-driven Thrust Bearing Test Rigmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Preliminary experimental study on static loading characteristics of multi-decked protuberant foil thrust bearing

Chen

et al. 2016

JAMDSM

Self Cite

“…4 a) and b). It was renovated based on the rig in Ref Lai, Guo, Wang, Chen and Hou, Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol.10, No.9 (2016) (Zhou et al, 2009). It was composed of four systems: high speed rotor-bearing system, loading system, high pressure gas supply system and data acquisition system.…”

Section: Experimental Test Rigmentioning

confidence: 99%

“…Somaya K. applied viscoelastic supports in thrust bearing (Somaya et al, 2009). Zhou Q. tested the dynamic characteristic of foil thrust bearing with viscoelastic support (Zhou et al, 2009). Following the design principles from Dellacorte C. (DellaCorte et al, 2008), Dykas B. outlined the fabrication of a modular thrust foil bearing (Dykas et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on multi-decked protuberant foil thrust bearing with different number of thrust pads

Guo

Wang

et al. 2016

JAMDSM

Self Cite

Thrust bearing is an important component in high speed rotor bearing system. For the thrust bearing, the pad circumferential partition is recognized as an essential factor for the foil thrust bearing in hydrodynamic lubrication. In this paper, performances of multi-decked protuberant foil thrust bearing (MDPFTB) with different pad numbers were experimentally studied on a thrust bearing test rig. Static deflection, transient start-up and transient loading performance of the thrust bearings of 3 pads, 4 pads and 6 pads were compared. The test results indicated that partition of thrust pad had a significant effect on the static and transient loading characteristics of the bearing. Radial vibration of the rotor-bearing system was coupled with the axial thrust bearing support condition. The axial supporting had limited effects on the lower order critical speeds in the radial direction. However, in higher speed range, more thrust pads could increase the second and higher critical speeds and suppress the vibration amplitude. The ultimate load capacity of the bearing increased with thrust pads. However, the available operational speed range was narrowed down. For the bearing with more thrust pads, load capacity decreased earlier in high speed range with softer static stiffness. The results may provide some design guides for application of protuberant foil thrust bearing.Key words : Load capacity, Protuberant foil, Rotor-bearing system, Thrust bearing IntroductionFoil bearing is a kind of aerodynamic bearing with layer(s) of resilient supporting foil and compliant top foil. Comparing to conventional ball bearings, it is more competitive in high speed and extreme environment occasions (Howard, et al., 2001a(Howard, et al., ,2001b (Hou, et al., 2004). It is widely used in high speed oil-free turbomachinery and motors owing to its stability, durability, tolerance, low power loss (Agrawal, 1997) ( Sim et al., 2015a( Sim et al., , 2015b (Hou et al., 2015).The rotor-bearing system usually consisted of a rotor supported by journal bearings and thrust bearings. A typical configuration of foil thrust bearings was shown in Fig. 1. In foil thrust bearing, conventionally, circular loading foils were split into a number of separated thrust pads circumferentially on account of thermal or loading conditions (Ryu and Andres, 2013) (Kim et al., 2011). Thrust pad number could be 3, 4, 6 and 8 etc. This not only modified the hydrodynamic pressure profile on the loaded thrust pad, but affected the frictional interaction between the foils. In each thrust pad, the top flat foil was supported by the elastic structure. From leading edge to trailing edge, the top foil and the supporting foil extended circumferentially with the same inner and outer diameter. The bearing stiffness depended on the gas film as well as on the configuration of the supporting elastic structure.In foil bearing, environment-friendly fluid such as air or nitrogen was a preferred choice for lubricant. However, the inherent low viscosity of such fluid restricted the...

“…Among them, bump type foil bearing attracted considerable attention [10]. Besides, metal mesh [11] and viscoelastic [12,13] configurations and so on have been presented. Foil bearing reduces the peak vibration amplitude notably when the rotor crosses the critical speed [14,15].…”

Section: Introductionmentioning

confidence: 99%

Development and Application of Integrated Aerodynamic Protuberant Foil Journal and Thrust Bearing in Turboexpander

International Journal of Rotating Machinery

Guo

Wang

et al. 2017

Self Cite

Foil bearing provides compliant support and moderate Coulomb friction for rotor-bearing system, which is conducive to stability and reliability of high speed rotating machinery. In this paper, both hydrodynamic lubricated foil journal and foil thrust bearings are applied in a 150 m 3 ⋅h −1 turboexpander for air separation. In the bearings, protuberant foil is chosen as the supporting subfoil due to its merits of easy fabrication and assembly. Static loading and deflection of the bearings are tested, respectively, before integration into the turboexpander. Afterwards, the loading and deflection curves of the journal and thrust bearings are polynomial fitted using least-square method. Then, performance tests are carried out on the rotor-bearing system, including transient speed-up, high speed, and speed-down processes. In the tests, the turboexpander supported by the hydrodynamic foil bearings operates smoothly with repeatability. Maximal rotor speed of the turboexpander reaches 52000 rpm with hydrodynamic lubricated protuberant foil bearings.