Externally pressurized gas journal bearing with slot restrictors arranged in the axial direction

Ise, Tomohiko; Nakatsuka, Masaya; Nagao, Kohei; Matsubara, Masami; Kawamura, Shozo; Asami, Toshihiko; Kinugawa, Tomoya; Nishimura, Kazuhiko

doi:10.1016/j.precisioneng.2017.05.016

Cited by 19 publications

(9 citation statements)

References 10 publications

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“…If the value does not converge, pressure boundary values will be set and equation 1is solved again until the pressure field is determined. The load force " F, stiffness " K, and gas flow rate " Q are obtained by using equations (11) to (13).…”

Section: Numerical Analysis Initial and Boundary Conditionsmentioning

confidence: 99%

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Static performance of the aerostatic journal bearing with grooves

Chen

Mills

Bao

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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Aerostatic bearings are widely employed in precision machines due to their properties of low friction, low heat conduction, and long-life operation. In this work, static performance of the journal bearing with rectangular grooves is investigated numerically. The effect of geometrical parameters such as axial groove length [Formula: see text], circumferential groove length [Formula: see text], orifice diameter df, groove depth gh, misalignment angles [Formula: see text] and [Formula: see text] on the load capacity [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are analyzed systematically. The resistance network method (RNM) is utilized to solve the Reynolds equation required in the analysis. Performance parameters including pressure distribution P, load force [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are examined in the simulations. It is revealed from the simulations that the proper value of axial groove length [Formula: see text] to obtain a better static performance varies from 1/8 to 1/2 when df varies between 0.11 and 0.29 mm, respectively. Therefore, a larger load force and stiffness can be obtained if [Formula: see text] is chosen to be 1/4, when diameter of the bearing orifice df equals 0.17 mm. It is also suggested that [Formula: see text] be chosen from the range of 1/6 and 1/3 to obtain a better static performance and a smaller gas flow rate. [Formula: see text] decreases with an increase in df when [Formula: see text] is set to be 1/8. However, the load force [Formula: see text] increases with an increase in df when [Formula: see text] varies from 3/8 to 1/2. [Formula: see text] has a significant influence on the changes of [Formula: see text] with df when [Formula: see text] is set to be constant. Therefore, df should be selected according to [Formula: see text] for an optimal design. The increase of misalignment angle [Formula: see text] leads to an increase in the load force [Formula: see text]. [Formula: see text] has little influence on the load force [Formula: see text]. Misalignment angles [Formula: see text] and [Formula: see text] have little influence on stiffness [Formula: see text] and gas flow rate [Formula: see text]. Therefore, it is preferable if [Formula: see text] is larger than 0 rad.

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Section: Numerical Analysis Initial and Boundary Conditionsmentioning

confidence: 99%

“…1–5 The static performance of aerostatic bearings is a significant aspect of its application. Their performance is significantly affected by many factors such as machining tolerances, 6 configuration structure, 7,8 feed system type, 9–13 bearing geometrical and operational parameters, 14–18 and grooves. 19–28 .…”

Section: Introductionmentioning

confidence: 99%

Static performance of the aerostatic journal bearing with grooves

Chen

Mills

Bao

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Obviously, the theoretical research becomes detailed. It's because gas bearing is widely used in various systems, such as spacecraft [10], satellite tests [11], turbomachine [12], medical equipment [13], computer memory devices [14], and precision machine tools [15], by different institutions and companies. NASA has applied gas bearing widely in the aerospace field [16], for example, Dellacorte studied design and performance of gas foil bearing [17] and applied them to the turbine engine [18], while Demag in Germany and Nakanishi in Japan have applied gas bearings to spindles and introduced typical products.…”

Section: Introductionmentioning

confidence: 99%

New Start-up Method for a Closed-Cycle Compression System with Gas Bearings and Its Characteristics

Lian

Hong

et al. 2020

Chin. J. Mech. Eng.

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Gas bearings, which have the advantages of low frictional resistance and power loss, high rotational speed and high temperature operation, and long life, are more suitable than are traditional liquid lubricated bearings because of their high precision, high rotational speed, and special condition support. However, the problem of starting a closed-cycle compression system with gas bearings still needs to be solved for practical application. Thus, a new start-up method for a closed-cycle compression system with aerostatic gas bearings is proposed in this paper. Further, this paper presents a numerical simulation and experimental investigation of the method’s feasibility and characteristics during the start-up process when the gas tank’s initial pressure is fixed. The results show that the gas tank volume is approximately directly proportional to the start-up time allowable, and a gas tank volume sufficiently small, which not only ensures the feasibility of start-up, but also affects other components only slightly, can be obtained. A perfect combination of radial and axial loads also can be achieved to make the start-up time allowable as long as possible. R134a is a better choice for the working medium than is air, as the start-up time allowable is longer, which leads to a smaller gas tank. This research proposes a new start-up method for a closed-cycle compression system with aerostatic gas bearings which has sufficient load capacity to support system during the start-up method.

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“…Performance of gas journal bearing with eight slots has been presented by Ise et al. 19 The authors obtained the results in terms of the pressure distribution, flow rate and load capacity.…”

Section: Introductionmentioning

confidence: 99%

“…Further, experimental investigation of slot-entry and hole entry bearings have been performed by Xu 18 and bearing dynamic and static performance were evaluated. Performance of gas journal bearing with eight slots has been presented by Ise et al 19 The authors obtained the results in terms of the pressure distribution, flow rate and load capacity.…”

Section: Introductionmentioning

confidence: 99%

Influence of bearing surface irregularities on hybrid slot-entry journal bearing with electrically conducting lubricant

Sahu

Sharma

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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This study concerns with the numerical simulation of a hybrid slot entry journal bearing lubricated with electrically conducting lubricant under the influence of magnetic field for both thermal and isothermal conditions. The Navier–Stokes equation has been used to formulate the flow of electrically conducting lubricant through slot restrictor and combining the Lorentz force in the equations of motion, together with the Ohm’s law and Maxwell equations. Further, the effect of surface irregularities on bearing surface is considered to analyse the performance of the slot-entry bearing. The surface irregularities asperity profile has been modelled in both axial as well as circumferential directions. Finite element method is used to solve the Modified MHD Reynolds equation. To compute the bearing performance characteristic parameters, a MATLAB source code based on Gauss–Seidel iteration method has been developed. A comparative numerical analysis has been carried out for an electrically conducting lubricant, Newtonian lubricant, bearing surface having irregularities and bearing with smooth surface. The numerically simulated results indicate that considering the bearing surface irregularities and MHD effects enhances the value of fluid film damping coefficients [Formula: see text] and the value of minimum fluid film thickness [Formula: see text].

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Externally pressurized gas journal bearing with slot restrictors arranged in the axial direction

Cited by 19 publications

References 10 publications

Static performance of the aerostatic journal bearing with grooves

Static performance of the aerostatic journal bearing with grooves

New Start-up Method for a Closed-Cycle Compression System with Gas Bearings and Its Characteristics

Influence of bearing surface irregularities on hybrid slot-entry journal bearing with electrically conducting lubricant

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