CFD investigation of pressure depressions in aerostatic circular thrust bearings

Eleshaky, Mohamed E.

doi:10.1016/j.triboint.2009.03.011

Cited by 96 publications

(66 citation statements)

References 16 publications

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“…Yoshimoto et al [9] investigated the flow structure in the bearing clearance of an aerostatic circular thrust bearing with a single inlet by solving the Navier-Stokes equation directly, and the results showed that the pressure recovery was caused by flow separation at the upper wall, and a decrease of air velocity after the minimum pressure was observed. Eleshaky [10] computationally studied the phenomenon of pressure depression in two configurations of aerostatic thrust bearings with recessed orifices and inherently compensated orifices and the results showed that the predicted pressure distributions along the fluid film are well comparable with the corresponding experimental data of other investigators. Renn et al [11] investigated the mass flow rate of aerostatic bearings with pocketed orifice-type restrictors experimentally and numerically by using CFD and the conclusions, which showed the CFD simulation results being in good agreement with experimental data.…”

Section: Introductionsupporting

confidence: 54%

“…The CFD turbulent models are carried out in the current study with the FLUENT s codes [10,30]. Due to the emergence of vortices in the chamber of orifice restrictors reported in reference [22] and rotation effects are considered in the simulation models, turbulence is modeled by using the RNG k-ε model with non-equilibrium wall functions (NEWF) [31].…”

Section: Computational Modelmentioning

confidence: 99%

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CFD based investigation on influence of orifice chamber shapes for the design of aerostatic thrust bearings at ultra-high speed spindles

Gao

Cheng

Chen

et al. 2015

Tribology International

110

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Section: Introductionsupporting

confidence: 54%

Section: Computational Modelmentioning

confidence: 99%

CFD based investigation on influence of orifice chamber shapes for the design of aerostatic thrust bearings at ultra-high speed spindles

Gao

Cheng

Chen

et al. 2015

Tribology International

110

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“…Also, CFD models can be used to study the pressure distribution; for example, in [5] the pressure depression effect in aerostatic thrust bearing is investigated. In [6], [7] CFD and FDM methods are applied to investigate static and dynamic behavior of bearings with small supply holes, the numerical results are also experimentally verified.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Squeeze Effect in a Gas Thrust Bearing

Colombo¹,

Moradi²,

Raparelli³

et al. 2017

Materials and Contact Characterisation VIII

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The squeeze effect of a gas thrust bearing is calculated using both a distributed parameters (DP) model and a lumped parameters (LP) model. A rectangular thrust bearing with no supply holes is considered in the analysis. In dynamic conditions, pressure values p1 and p2 are calculated. In steady-state conditions, these values coincide with ambient pressure pa. The developed LP model was validated with the DP model for a pad shape ratio (length/width) in the range of 0.5 to 2. Both models are validated in the literature in about a 1D parallel slider. The LP model has the advantage of faster implementation in comparison to the DP model. The LP model is also linearized by using a perturbation method to obtain the analytic expression of the dynamic stiffness. Therefore, it is possible to explain the effect of geometrical parameters on stiffness and damping coefficients. Keywords: squeeze film air thrust bearing, lumped parameters model, dynamic stiffness. INTRODUCTION Recently in literature, most of the air bearings are analyzed with distributed parameters (DP) methods, using finite difference technique (FDM) [1], [2] or finite element method (FEM)[3], [4]. Also, CFD models can be used to study the pressure distribution; for example, in [5] the pressure depression effect in aerostatic thrust bearing is investigated. In [6], [7] CFD and FDM methods are applied to investigate static and dynamic behavior of bearings with small supply holes, the numerical results are also experimentally verified. In [8] a multi-physics finite element model is adopted to consider the interaction between the air flow dynamics and the structural flexibility of the bearing.Generally, all these methods achieve high precision in results but the solution can require long computation time due to the high number of nodes used for the discretization of the pad surface. Also, the identification of the parameters that influence the behavior is not easy.A lumped parameters model can be alternatively used as a fast design tool for air bearings. It does not require the use of commercial software and can be successfully adopted both for static and dynamic study. Due to its quite good precision and low number of parameters, this method allows an easy design and understanding of the phenomena.For simple geometries, analytical and lumped parameters methods were preferred in the past, when the computational speed was not high. Paper [9] presents analytical study of static characteristics of the bearings, papers [10], [11] show dynamic performance and stability criteria of aerostatic bearings adopting linearized equations of motion.Recently in [12] a lumped parameters model is proposed to study the static performance of a multiple supply holes rectangular pad. The results of load capacity, stiffness and air consumption were obtained in dimensionless form by chancing position, numbers and diameters of supply holes.About the dynamic behavior of air pads in [13] the time response of the force to a step variation of the air gap is analyzed. Results with ...

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“…A multiphysics finite element model can also be used to consider the interaction between the air flow dynamics and the bearing's structural flexibility, as for example in [18]. Recently, computational fluid dynamics (CFD) was used jointly with experimental activities to improve the description of the flow field near the supply holes [19][20][21][22][23]. In [24,25], by contrast, semi-analytical methods were employed to determine orifice discharge coefficients, which were then used in analytical formulations.…”

Section: Introductionmentioning

confidence: 99%

Lumped parameters models of rectangular pneumatic pads: Static analysis

Colombo

Raparelli

Trivella

et al. 2015

Precision Engineering

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a b s t r a c t A lumped parameters model of a rectangular pneumatic pad is developed and static analysis is performed. The model can be implemented more quickly than a distributed parameters model and is equally accurate. The influence of geometric parameters is discussed to help the reader in the design of pneumatic pads. Analysis is carried out in dimensionless form to obtain results of general validity.

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CFD investigation of pressure depressions in aerostatic circular thrust bearings

Cited by 96 publications

References 16 publications

CFD based investigation on influence of orifice chamber shapes for the design of aerostatic thrust bearings at ultra-high speed spindles

CFD based investigation on influence of orifice chamber shapes for the design of aerostatic thrust bearings at ultra-high speed spindles

Evaluation of Squeeze Effect in a Gas Thrust Bearing

Lumped parameters models of rectangular pneumatic pads: Static analysis

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