Article
Engineering, Chemical
Can Ma, Qichao Yang, Xiaohang Sun, Kelong Zhang, Liansheng Li
Summary: In this study, the performance of an externally pressurized gas journal bearing lubricated with R134a vapor in an oil-free refrigeration centrifugal compressor is investigated using the finite difference method (CFD) to solve the Reynold equations. The load capacity, stiffness, and mass flow rate of the refrigerant vapor are obtained under various operational parameters and compared with those in air gas bearings. The effects of average clearance, eccentricity ratios, and supply vapor pressure on the static characteristics of journal bearings are discussed in detail. The study concludes that the optimal operational parameters for R134a vapor gas journal bearings are different from air journal bearings, and these factors should be considered in the design process.
Article
Chemistry, Physical
Han Yan, Changlei Ke, Nan Peng, Kongrong Li, Xiaohua Zhang, Lianyou Xiong, Bin Dong, Jing Li, Liqiang Liu
Summary: This paper introduces a new simplified load capacity prediction model for high-speed externally pressurized hydrogen journal bearings to optimize their performance. The model allows for accurate calculation of the bearing load capacity without the need for complex numerical analysis and computer programming. Experimental results show that the predicted model aligns well with results obtained from finite difference method technique.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Engineering, Mechanical
Chuanbing Zhang, Hongrui Ao, Hongyuan Jiang
Summary: Hybrid gas dynamic bearings (HGDBs) are designed to enhance the viscous damping and stiffness of conventional gas foil bearings (GFBs). The coupling of rarefied gas effect, roughness effect, and gas leakage effect decreases the static load-carrying capacity, while dynamic coefficients are influenced by the dynamic sliding bearing model.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Chemistry, Multidisciplinary
Gregor Schilling, Robert Liebich
Summary: This paper investigates the influence of a nominal bearing clearance on the lift-off behavior and load-carrying capacity of gas polymer bearings (GPBs). An experimental study with five different bearing gap configurations and a range of static loads is conducted. The results show significant differences in the load-carrying capacity between bump-type and gas polymer bearings, and the effects are described and explained. The findings highlight the importance of considering these differences in the design process of rotors supported in GPBs.
APPLIED SCIENCES-BASEL
(2023)
Article
Acoustics
Sebastian von Osmanski, Ilmar F. Santos
Summary: Gas foil bearings have the potential for oil-free and environmentally friendly support of high-speed rotating machinery, but face technical limitations when applied in heavier machinery. Hybridizing gas foil bearings with radial gas injection may be a possible solution to overcome these limitations.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Computer Science, Interdisciplinary Applications
Manuel Viermetz, Nikolai Gustschin, Clemens Schmid, Jakob Haeusele, Bernhard Gleich, Bernhard Renger, Thomas Koehler, Franz Pfeiffer
Summary: X-ray computed tomography (CT) is an important imaging technique in clinical diagnostics. Dark-field CT, which provides additional microstructural information, has shown potential clinical value. In this paper, the performance of a prototype dark-field CT system is discussed, including the evaluation of the interferometer components and challenges related to integration into the CT gantry. The impact of the X-ray source and vibrations on the system are analyzed, and a beam hardening correction is introduced to enable quantitative dark-field imaging. The resolution and patient dose are also analyzed, and initial patient studies using the presented dark-field CT system are suggested.
IEEE TRANSACTIONS ON MEDICAL IMAGING
(2023)
Article
Engineering, Mechanical
Chengjun Rong, Huaqi Lian, Yulong Li
Summary: The study found that thrust bearings lubricated with refrigerant gases exhibited higher static stiffness when the bearing clearance was less than 9μm, but lower load capacity compared to N2-lubricated bearings. The optimal static stiffness of R22- and CO2-lubricated bearings increased by more than 46% and more than 21%, respectively, compared to N2-lubricated bearings. The results suggest that a small bearing clearance is preferable when designing externally pressurized gas thrust bearings lubricated with the working medium of heat pump systems for space applications.
INDUSTRIAL LUBRICATION AND TRIBOLOGY
(2021)
Article
Engineering, Mechanical
Wanhui Liu, Philipp Baettig, Patrick H. Wagner, Juerg Schiffmann
Summary: This study investigates the nonlinear behavior of a rigid rotor supported by herringbone grooved journal gas bearings (HGJBs) using the two-dimensional narrow groove theory (2D-NGT). The theoretical model is successfully validated by experimental data in predicting the onset speed of sub-synchronous vibration and whirl frequency ratio of the HGJB-rotor system, showing the stability changes under different static load conditions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Engineering, Mechanical
Hongyang Hu, Ming Feng, Tianming Ren
Summary: A new type of gas foil conical bearing was proposed to reduce the mass and size of low-power turbine machinery, with its static and dynamic performance systematically studied. The results show that the new bearing has excellent supporting performance and broad prospects for application, with parameters such as bump radius, rounding radius, friction coefficients, and foil thickness significantly influencing the bump foil stiffness.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Engineering, Chemical
Huaqi Lian, Chengjun Rong, Yulong Li
Summary: The study found that increasing bearing surface temperature leads to an increase in load but an initial increase and subsequent decrease in static stiffness, while increasing supply gas temperature results in a decrease in both load and static stiffness. These insights can be valuable for designing gas bearings using refrigerant gases.
Article
Engineering, Mechanical
Rui Chen, Yong Zhao, Jiakang Yao, Zixi Wang
Summary: This paper investigates the influence of angular disturbances on foil thrust bearings and establishes a dynamic model with an angular swinging bearing pad. The results show that the load-carrying capacity of the bearing can be enhanced by introducing a proper angular tracking ability.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Mechanical
Zhenni Xu, Changlin Li, Jianjun Du, Jie Li, Yuechang Wang
Summary: This paper proposes a comprehensive model to improve the load capacity of gas foil thrust bearings (GFTBs), combining with the analysis of arbitrarily shaped foils. The model considers bump interactions, frictional forces, and the geometry of foils and bump height errors. The accuracy of the model is verified by comparison with commercial software simulations, experimental data, and literature results. This study also fills a knowledge gap by obtaining the effects of bump height errors on bearing load-carrying performance. The results can provide guidance for bearing designers.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Mechanical
Hongyang Hu, Ming Feng, Tianming Ren
Summary: The addition of shim foil under the bump foil of gas foil journal bearings (GFJBs) can significantly increase the load capacity and direct stiffness, especially with the presence of preload, while also improving stability. The stability threshold speed (STS) of rotors supported by the novel GFJBs is enhanced, indicating better stability.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Acoustics
Yuqing Liu, Zaigang Chen, Kaiyun Wang, Wanming Zhai
Summary: This study establishes a dynamic model of the rotor-bearing system, considering the time-varying mesh stiffness of gear pair, interactions between the roller and race of support bearings, and dynamic forces induced by dynamic rotor eccentricity. In addition, a spatial rolling bearing dynamics model is used to analyze the effect of traction torque, rotor eccentricity, and external excitation on the system.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Engineering, Mechanical
Donghyun Lee, Hyungsoo Lim, Byungock Kim, Byungchan Jeon, Junyoung Park
Summary: This study developed an externally pressurized bearing for a turbo expander used in a hydrogen liquefaction plant. The rotor-bearing system was designed through numerical modeling, and its performance was analyzed. The results showed that the system had sufficient separation margin with the critical speed and the predicted critical speed matched well with the simulation.
Article
Engineering, Mechanical
Tomohiko Ise, Naoyuki Arita, Toshihiko Asami, Iwao Kawashima, Tadashi Maeda, Takenori Nakajima
MECHANISM AND MACHINE THEORY
(2015)
Article
Engineering, Mechanical
Tomohiko Ise, Shuma Kobayashi, Kazuhiro Itoh, Toshihiko Asami
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2017)
Article
Engineering, Multidisciplinary
Tomohiko Ise, Masaya Nakatsuka, Kohei Nagao, Masami Matsubara, Shozo Kawamura, Toshihiko Asami, Tomoya Kinugawa, Kazuhiko Nishimura
PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY
(2017)
Article
Engineering, Manufacturing
Tomohiko Ise, Hiroshi Miyatake, Toshihiko Asami
JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING
(2012)
Article
Mechanics
Hajime Kishi, Atsushi Nagao, Yusaku. Kobayashi, Satoshi Matsuda, Toshihiko Asami, Atsushi Murakami
NIHON REOROJI GAKKAISHI
(2008)
Article
Engineering, Multidisciplinary
Tomohiko Ise, Naoyuki Arita, Toshihiko Asami, Takenori Nakajima, Iwao Kawashima, Tadashi Maeda
PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY
(2014)
Article
Acoustics
Toshihiko Asami
JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME
(2019)
Proceedings Paper
Engineering, Mechanical
Yuichi Baba, Kento Onishi, Toshihiko Asami
PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE, 2017, VOL 5
(2017)
Article
Acoustics
Toshihiko Asami
JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME
(2017)
Article
Acoustics
Toshihiko Asami, Yasutaka Yokota, Tomohiko Ise, Itsuro Honda, Hiroya Sakamoto
JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME
(2013)
Article
Acoustics
Toshihiko Asami, Yasutaka Yokota, Tomohiko Ise, Itsuro Honda, Hiroya Sakamoto
JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME
(2013)
Proceedings Paper
Engineering, Civil
Toshihiko Asami, Yasutaka Yokota, Tomohiko Ise, Ltsuro Honda, Hiroya Sakamoto
PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE, PVP 2012, VOL 8
(2012)
Article
Polymer Science
Hajime Kishi, Atsushi Nagao, Yusaku Kobayashi, Satoshi Matsuda, Toshihiko Asami, Atsushi Murakami
JOURNAL OF APPLIED POLYMER SCIENCE
(2007)
Article
Acoustics
Toshihiko Asami, Yoshito Mizukawa, Tomohiko Ise
JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME
(2018)