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

Abstract

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.

Parametric Studies on Performance of Oil-Free Thrust Foil Bearings at Lower Speeds

“…The performance of FTB in terms of coefficient of friction, load capacity, and temperatures was evaluated for grooved foils by Hyuga and others [2] for lower speeds. Similar performance tests were conducted on hydrodynamic gas foil journal bearing (GFJB) and foil thrust bearing (FTB) on a turbo-expander by T Lai et al [3] for rotating speeds up to 52,000 rpm. Effect of foil stiffness and RESEARCH nominal clearance on static performance of GFTB with top foil, bump foil, and supporting foil were tested for a centrifugal air compressors by Ting Shi and others [4].…”

Gas Bearings: Modelling, Design and Applications

“…In 2012, in order to analyze the feasibility of the application of protuberant foil journal bearings in a turbo-expander, another experimental study was carried out. The results showed that the maximum speed of the turbo-expander reached 99,044 rpm, and the low-frequency whirl motion was small during the entire speed-up and speed-down process [45][46][47]. In the total protuberant foil bearing test (both journal and thrust bearings are protuberant type), the gas foil bearing ran smoothly and had high repeatability during the operation of the turbo-expander [15].…”

Experimental analysis of influence of double-layer bump foils on aerodynamic thrust foil bearings performance

“…In addition to bump foils can be used as bearing support components; protuberant foils can also be used as bearing elastic support components to form protuberant foil bearings (Hou et al, 2011;Lai et al, 2017;Pan et al, 2018;Zheng et al, 2016aZheng et al, , 2016b. For this type of bearing, researchers have also tried to use double foil to improve the performance of bearings.…”