Effect of recess geometry on shock wave formation in circular gas bearings

Salem, E.A.; Kamal, W.A.

doi:10.1016/0043-1648(78)90039-x

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…Due to the complexity of three-dimensional gas flow and some assumptions in solving the Reynolds equation, the traditional Reynolds equation was insufficient to capture these phenomena accurately. Gradually, more flow characteristics such as supersonic flow, turbulence, gas vortex, and shock wave were discussed [11][12][13][14]. The flow characteristics and fluctuating pressure of ATB are shown in Figure 3 [15].…”

Section: Theoretical Modelmentioning

confidence: 99%

Research Developments of Aerostatic Thrust Bearings: A Review

et al. 2022

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In aerostatic thrust bearings (ATBs), a high-pressure gas film with a certain bearing capacity and stiffness is formed by passing high-pressure gas between the moving surface and the static surface. Aerostatic bearings have outstanding advantages in the following aspects: high precision, high speed, and long service life, etc. They are widely used in many fields, such as high-speed air spindles, precision machine tools, air-bearing guideways, turbine machinery, and high-speed drills. With the pursuit of higher efficiency and high-precision machining machinery, there is an increasing demand for high-performance ATBs. Much effort has been spent on the study of ATBs, such as improvements in load capacity and stiffness, and the enhancement of stability. Some significant progress has been achieved. In this paper, the research developments of ATBs are summarized from several aspects, such as theoretical models and experimental methods, static performance, dynamic performance, and applications. In addition, insights on the breakthrough and development trends of ATBs are put forward. It is hoped that this paper can provide some guidance for the design and application of ATBs.

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Section: Theoretical Modelmentioning

confidence: 99%

Research Developments of Aerostatic Thrust Bearings: A Review

et al. 2022

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“…However, while the chamber in the orifice−type aerostatic bearing enhances static performance, it simultaneously exacerbates pressure fluctuations and self−excited vibrations, thereby limiting motion positioning accuracy. Therefore, numerous studies have examined the complexities of pressure fluctuations and turbulent vortices near outward orifices [19,20]. Fourka et al [21] established a non−linear model based on the finite element method to analyze the stability of air thrust bearings, revealing that the linear analysis underestimates the stability threshold compared with their non−linear model.…”

Section: Introductionmentioning

confidence: 99%

Static and Dynamic Performances of Novel Aerostatic Bearings with Primary and Secondary Orifice Restrictors

Yu,

Zuo,

et al. 2023

Lubricants

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Aerostatic bearings are crucial support components in ultra−precision manufacturing equipment. However, improvements in the load−carrying capability (LCC) of aerostatic bearings often lead to higher intensity nano−vibrations. This paper introduces a novel primary and secondary orifice restrictor (PSOR) designed to simultaneously enhance the LCC and mitigate nano−vibrations in aerostatic bearings. The static performance of complex turbulent flows occurring within the chamber of aerostatic bearings with PSORs was investigated. The dynamic performance of the turbulent flows was analyzed through 3D transient numerical simulation using the large eddy simulation method. The LCC and nano−vibration acceleration were measured experimentally, and the results indicated that the design of the secondary orifice diameter could enhance LCC and mitigate nano−vibrations, consistent with theoretical predictions. The accuracy of the proposed model was validated, confirming the effectiveness of PSOR. In the experiments, an aerostatic bearing with a secondary orifice diameter of 0.1 mm exhibited the lowest LCC and largest nano−vibration. Conversely, an aerostatic bearing with a secondary orifice diameter of 0.26 mm exhibited the highest LCC and weakest nano−vibration. This study provides insights into the formation mechanism of turbulent vortex and interaction mechanism among the primary orifice and secondary orifices in aerostatic bearings with a PSOR.

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“…Mori et al (1964) investigated theoretically the pressure distribution in externally pressurized circular thrust gas bearings with a circular recess also by assuming the generation of a normal shock wave in the bearing recess. Salem and Kamal (1978) researched the effect of recess geometry on normal shock wave formation in a circular gas bearing to determine the limiting conditions for shock-free operation. Yoshimoto et al (2007) discussed the flow structure of an aerostatic circular thrust bearing and noted that after entering the bearing clearance the airflow becomes turbulent.…”

Section: Introductionmentioning

confidence: 99%

Study on the one-dimensional governing equations of aerostatic circular thrust bearing with a single air supply inlet

Gao

Nong

2022

ILT

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Purpose The purpose of this paper is to derive the one-dimensional governing equations to describe the pressure distribution, load capacity and stiffness of aerostatic circular thrust bearing with a single air supply inlet. Design/methodology/approach The film flow field is divided into four regions: supply pressure region, pressure dropping region, pressure rising region and laminar flow region. The influences of bearing clearance and supply pressure on the pressure distribution, load capacity and stiffness of the bearing are presented. Findings With the large film clearance and large supply pressure, the oblique shock wave occurs near the entrance of gas film, which greatly increases the pressure drop region. Hence, it is not appropriate to consider the oblique shock as a normal shock. Originality/value This paper introduces the invariants at the entrance of gas film, employs the functional relationships between density and pressure, and provides the empirical formulas for the pressure dropping and rising regions. The pressure distribution curves are therefore illustrated through a considerably simplified computational process.

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Effect of recess geometry on shock wave formation in circular gas bearings

Cited by 9 publications

References 3 publications

Research Developments of Aerostatic Thrust Bearings: A Review

Research Developments of Aerostatic Thrust Bearings: A Review

Static and Dynamic Performances of Novel Aerostatic Bearings with Primary and Secondary Orifice Restrictors

Study on the one-dimensional governing equations of aerostatic circular thrust bearing with a single air supply inlet

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