Investigation on backflow phenomenon in the aerostatic journal bearing

Chen, Xinglong; Bao, Gang; Mills, James K.

doi:10.1177/1350650119870965

Cited by 8 publications

(5 citation statements)

References 42 publications

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“…The performance parameters of an aerostatic journal bearing with partially blocked feeding holes are theoretically investigated in this study. Before the simulation results were presented, in order to validate the numerical solution technique, simulation results were compared with the published experimental and numerical data given in the literature, 15,28 respectively. In this comparison study, geometric specifications of the aerostatic bearing are given in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Performance characteristics of an aerostatic journal bearing with partially blocked orifices

Dal

Karaçay

2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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Aerostatic journal bearing applications mainly focus on high-speed precision machining, so predictable and smooth functioning of the system is crucial. Air is supplied to the bearing through a number of orifices and any unevenness in the size of these orifices will affect the performance of the system. The size difference could be due to manufacturing error and/or blockage of the orifice because of foreign materials in the air system. In this study, the performance of an aerostatic bearing with a partially blocked orifice is numerically investigated. Firstly, the airflow in the bearing clearance was modeled with Reynolds equation and this equation was numerically solved with the finite difference and differential transform hybrid method to obtain the pressure distribution. Then, the force and the stiffness are calculated from the pressure distribution for different blockage cases of the orifice and different blockage ratios. The results show that the partial blockage of the orifice significantly changes the performance of the system in a positive or a negative way according to the feeding hole position, and the blockage ratio also affects performance.

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Section: Resultsmentioning

confidence: 99%

Performance characteristics of an aerostatic journal bearing with partially blocked orifices

Dal

Karaçay

2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…The journal bearing with two sets of eight orifices with equal spacing on the surface is manufactured and assembled in the pneumatic cylinder to produce a frictionless motion, as shown in Figure 1(a). The working principle of the bearing–cylinder system is presented in detail by Chen et al 26 To improve the static performance of the bearing, pockets with different shapes are manufactured on the surface, with the same dimensions of the pocket at each orifice for each pocket shape shown in Figure 1(c). To facilitate the investigation, pockets of each shape have the same pocket area S false¯.…”

Section: Mathematical Modelingmentioning

confidence: 99%

Numerical investigation on the static performance of aerostatic journal bearings with different pocket shapes by the finite-element method

Chen

Mills

Shi

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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In this work, to improve the static behavior of aerostatic journal bearings, we examine the effect of pockets with different shapes, including the square, rectangular 1, rectangular 2, and circular, manufactured on the surface of the aerostatic journal bearing. The effects of the pocket shapes, pocket area [Formula: see text], eccentricity ratio ɛ, orifice diameter df, average gas film thickness h0, and misalignment angles [Formula: see text] and [Formula: see text] on the static performance are investigated using simulations. The Reynolds equation is solved by the finite-element method in this work. Simulations reveal that the pocket area [Formula: see text], eccentricity ratio ɛ, gas film thickness h0, orifice diameter df, and misalignment angles [Formula: see text] and [Formula: see text] have a significant influence on the load force F and the stiffness K. In general, rectangular 2 pocket bearings are found to perform somewhat better than bearings with other pocket shapes, with the pocket depth set to one-half of h0, when the pocket area [Formula: see text] varies from one-twelfth to one. The pocket area [Formula: see text] should be set according to the average gas film thickness h0 and the orifice diameter df to achieve a better static performance for the bearings. For bearings operated with misalignment angles [Formula: see text] and [Formula: see text], different pocket areas [Formula: see text] should be set according to the pocket shapes for the optimal design.

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“…The working principle and application of the gas bearing with grooves, proposed in this work, is similar as that of the bearing without grooves. 30 In practice, there may be a torque caused by the eccentricity of the load gravity center G in the engineering applications as shown in Figure 1, giving a misalignment angle to the journal bearing. Besides, it is required that the journal bearing has a better static performance to counterweight the unbalance force.…”

Section: Mathematical Modelingmentioning

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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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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Investigation on backflow phenomenon in the aerostatic journal bearing

Cited by 8 publications

References 42 publications

Performance characteristics of an aerostatic journal bearing with partially blocked orifices

Performance characteristics of an aerostatic journal bearing with partially blocked orifices

Numerical investigation on the static performance of aerostatic journal bearings with different pocket shapes by the finite-element method

Static performance of the aerostatic journal bearing with grooves

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