Gotowe bibliografie tematyczne / Shape pad thrust bearings

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Gotowa bibliografia na temat „Shape pad thrust bearings”

Autor: Grafiati

Data publikacji: 6 września 2023

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Artykuły w czasopismach na temat "Shape pad thrust bearings"

Jeng, M. C., G. R. Zhou i A. Z. Szeri. "A Thermohydrodynamic Solution of Pivoted Thrust Pads: Part I—Theory". Journal of Tribology 108, nr 2 (1.04.1986): 195–207. http://dx.doi.org/10.1115/1.3261160.

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The object is construction of a thermohydrodynamic theory of thrust bearings. The bearing pad has the geometry of an annular sector and is supported in one point; about this point it is free to pivot. The film shape is arbitrary, thus permitting specification of thermal-elastic deformation and/or crowning of the pad. The lubricant which is interposed between bearing pad and runner has temperature dependent viscosity. The lubricant flow may be laminar or turbulent. The numerical method employed in this work is the method of Finite Differences for the pressure equation and Galerkin’s method with B-spline test functions for the energy equation.

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Aggarwal, Shipra, i R. K. Pandey. "Performance investigation of micro-pocketed textured pad thrust bearing". Industrial Lubrication and Tribology 70, nr 8 (12.11.2018): 1388–95. http://dx.doi.org/10.1108/ilt-10-2017-0302.

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Purpose The purpose of this paper is to conceive a new surface texture incorporating a tiny shape among the micro-pockets (with circular, rectangular, trapezoidal and triangular cross-sections) and dimples (cylindrical, hemispherical and ellipsoidal) for exploring to enhance the maximum possible performance behaviors of sector shape pad thrust bearing. Design/methodology/approach Numerical simulation of hydrodynamically lubricated sector shape textured pad thrust bearing has been presented incorporating thermal and cavitation effects. The coupled solution of governing equations (Reynolds equation, film thickness expression, viscosity–temperature relation, energy equation and Laplace equation) has been achieved using finite difference method and Gauss–Seidel iterative scheme. Findings With new textured pads, higher load-carrying capacity and lower coefficient of friction are obtained in comparison to plain sector shape pad. Texture pattern comprising square cross-sectional pockets yields higher load-carrying capacity and lower coefficient of friction in comparison to other cross-sectional shapes (circular, trapezoidal and triangular) of pockets considered herein. Originality/value This study reports a new texture, which involves micro-pockets of square cross-sectional shapes to improve the performance behavior of sector shape pad thrust bearing. About 75 per cent increase in load carrying capacity and 42 per cent reduction in coefficient of friction have been achieved with pad having new texture in comparison to conventional pad.

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Fesanghary, M., i MM Khonsari. "On the modeling and shape optimization of hydrodynamic flexible-pad thrust bearings". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 227, nr 6 (6.12.2012): 548–58. http://dx.doi.org/10.1177/1350650112464323.

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J.C. Blanco, Claudio, Alvaro T. Prata i Francisco C.L. Pessoa. "Simulation and optimization of thrust circular bearings with planes sector-shaped". Industrial Lubrication and Tribology 66, nr 1 (4.02.2014): 75–82. http://dx.doi.org/10.1108/ilt-07-2011-0052.

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Purpose – The purpose of this paper is to analyze journal thrust bearings geometries, used in household refrigerators, using a modified version of the Reynolds equation which includes the inertial terms. Design/methodology/approach – The Reynolds equation was solved through the finite volume method, thus providing the pressure field in the lubricant film and, consequently, the load and the power used by the bearing. Such parameters depend on bearing geometry, which was optimized through the method of Lagrange multipliers, to support a given load and use the lowest power possible. The optimized geometries included the Rayleigh pad with 4, 8 and 16 steps, and a milled geometry with 4 steps. Findings – For the Rayleigh pad, the number of steps was varied and a decrease in the power consumed with the increase in the number of steps was observed. The milled pad performance was better than that Rayleigh pad with 4 steps and comparable to the pad with 8 steps. Originality/value – The manufacture of pads, with a high number of steps, is complicated and, then, a milled pad with 4 steps was proposed in this paper. The use of milled pads is a technological innovation worthy of a more thorough investigation, considering its facility of manufacture when compared to the Rayleigh pad.

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Yadav, Saurabh K., i Satish C. Sharma. "Finite element analysis of tilted thrust pad bearings of various recesses shapes considering thrust pad flexibility". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 230, nr 7 (3.12.2015): 872–93. http://dx.doi.org/10.1177/1350650115619610.

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Hashimoto, H., i S. Wada. "Turbulent Lubrication of Tilting-Pad Thrust Bearings With Thermal and Elastic Deformations". Journal of Tribology 107, nr 1 (1.01.1985): 82–86. http://dx.doi.org/10.1115/1.3261006.

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Pad deformations of sector-shaped, tilting-pad thrust bearings affecting turbulent lubrication are discussed theoretically. Solving the lubrication and energy equations with turbulence and centrifugal forces and the elastic and moment balance equations of a pad simultaneously, film pressure and temperature distributions, thermal and elastic deformations and inclinations of a pad are obtained. Film thicknesses at a pivot under a constant shaft speed become larger due to pad deformations, whereby pad inclinations increase and friction torque coefficients decrease outstandingly. It is important to introduce the effects of pad deformations when analysing performances of such bearings running in the turbulent conditions.

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Yu, Xiao Dong, Zhen Guo Li, De Fan Zhou, Heng Wei Li, Chun Li Gao, Zhi Xin Qiu, Bo Wu, Yan Qin Zhang, Bai Qin i Xue Zhe Dong. "Influence Research of Recess Shape on Dynamic Effect of Hydrostatic Thrust Bearing". Applied Mechanics and Materials 274 (styczeń 2013): 57–60. http://dx.doi.org/10.4028/www.scientific.net/amm.274.57.

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This work describes a simulation research concerning dynamic effect of multi-pad hydrostatic thrust bearing having rectangular recess, sector recess, ellipse recess and I-shaped recess in order to solve the loading capacity of the hydrostatic thrust bearing. Three-dimensional pressure field of gap fluid between the rotation worktable and the base has been computed by using the Finite Volume Method. This study theoretically analyzes the influence of recess shape on dynamic effect of the bearing according to computational fluid dynamics and lubricating theory, and the simulation results indicate that an improved characteristic will be affected by recess shape easily. Through this method, the safety of a multi-pad hydrostatic thrust bearing having different cavities can be forecasted, and the optimal loading capacity of such products can be achieved, so it can provide reasonable data for design, lubrication, experience and thermal deformation computation for hydrostatic thrust bearing.

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Medeiros, Nielson Veloso, Emanuel Negrão Macêdo, Rui Nelson Otoni Magno, Claudio José Cavalcante Blanco i João Nazareno Nonato Quaresma. "Integral transform solution for the analysis of hydrodynamic lubrication of thrust bearings". Industrial Lubrication and Tribology 69, nr 6 (13.11.2017): 1074–84. http://dx.doi.org/10.1108/ilt-08-2016-0187.

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Purpose The aim of this paper is related to an analysis of hydrodynamic lubrication of circular thrust bearings. Design/methodology/approach The modified Reynolds equation was treated to obtain a hybrid numerical-analytical solution through the generalized integral transform technique (GITT) for the problem. Findings Numerical results for the engineering parameters such as pressure field, load capacity and power consumption were thus produced as functions of the radial and circumferential directions. These parameters depend on the geometry of sector-shaped used: Rayleigh pad with 4, 8 and 16 steps. Comparing among them, on the numerical point of view, the Rayleigh pad geometry with N = 16 steps has a better satisfactory performance because it has a lower power consumption. Originality/value The present GITT results and those obtained by the finite volume method (FVM) from previous works in the literature were confronted to verify whether the results are consistent and to demonstrate the capacity of the GITT approach in handling thrust bearing problems.

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Bassani, R., E. Ciulli i P. Forte. "An investigation on thrust bearing tilting pads". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 212, nr 4 (1.04.1998): 271–77. http://dx.doi.org/10.1243/1350650981542083.

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The present work regards the first stage of a research activity aimed at the understanding of the phenomena involved in the working of thrust bearing tilting pads. Three pads of the same shape and dimensions with different pivot positions have been studied. An experimental investigation is carried out on the pads using a particularly versatile test rig. Simultaneous measurements of film thickness, pad tilt and frictional force are made; in particular the tilt angle is measured by optical interferometry with monochromatic light. Experimental results are compared with numerical data. A finite element method code is used to calculate the pressure field of the finite thrust pad. For a given pivot film thickness an iterative procedure yields the tilt angle using the condition of zero moment about the pivot. First results indicate the way to future investigations.

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Shao, Jun-peng, Guang-dong Liu i Xiaodong Yu. "Simulation and experiment on pressure field characteristics of hydrostatic hydrodynamic hybrid thrust bearings". Industrial Lubrication and Tribology 71, nr 1 (14.01.2019): 102–8. http://dx.doi.org/10.1108/ilt-02-2018-0063.

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PurposeThis paper aims to improve the bearing capacity of hydrostatic thrust bearing under working conditions of high speed and heavy load; a new wedge-shaped structure opened on an edge of oil seal is put forward, the loss and insufficiency for hydrostatic bearing capacity are made up by using dynamic pressure, and then, hydrostatic hydrodynamic lubrication is realized.Design/methodology/approachOil film three-dimensional models of unidirectional and bi-directional hydrostatic hydrodynamic oil pad are established by using UG. The oil film pressure fields of two kinds of oil pad are simulated by using ANSYS ICEM CFD and ANSYS CFX; the pressure fields distribution characteristics are obtained, and the effects of workbench rotary speed and bearing weight on pressure field are analyzed. Also, the experimental verification is made.FindingsThe results demonstrate that with an increase in workbench rotary speed, the oil film pressure of two kinds of hybrid oil pad increases gradually, and the maximum pressure of the bi-directional one accounts for 95 per cent of the unidirectional one when the load is constant. With an increase in load, the oil film pressure of two kinds of hybrid oil pad increases gradually, the difference between them is 9.4 per cent under the condition of load of 25twhen the rotary speed is constant.Originality/valueThe paper can provide theoretical basis for a structure design of hybrid thrust bearing under different rotary speed and load conditions, and compensate the shortage of static pressure-bearing capacity by using dynamic pressure, improve the stability of vertical CNC machining equipment.

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Rozprawy doktorskie na temat "Shape pad thrust bearings"

Glavatskikh, Sergei B. "On the hydrodynamic lubrication in tilting pad thrust bearings /". Luleå, 2000. http://epubl.luth.se/1402-1544/2000/34/index.html.

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Charitopoulos, Anastasios. "Computational Fluid Dynamics study of heavily loaded fixed-pad thrust bearings operating under thermoelastohydrodynamic regime". Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2285.

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Dans la présente thèse sont étudiés les effets des déformations thermiques sur les performances des butées à patin fixe fonctionnant sous des charges et des températures élevées. Le travail présenté se compose de deux parties principales. Dans une première étape, afin d'identifier les mécanismes de génération de pression dans les butées à surfaces parallèles, les différentes théories proposées dans la littérature scientifique ont été évaluées. À cette fin, un modèle thermoélastohydrodynamique (TEHD) basé sur la Dynamique de Fluides Numérique (CFD) a été généré, en tenant compte tous les phénomènes physiques du lubrifiant, des solides et de leur interaction, qui ont été suggérés dans la littérature comme des phénomènes contribuant au mécanisme de génération de pression des butées à faces parallèles. L'importance de chaque théorie a été quantifiée et une modélisation finale a été proposée afin d’évaluer avec précision les performances d'une butée à faces parallèles. De plus, le modèle généré a été validé par rapport aux résultats expérimentaux de la littérature. La deuxième partie de la thèse utilise l'approche de modélisation proposée précédemment pour évaluer les conceptions contemporaines de butées, telles que les butées à surfaces texturées, revêtus, à poche et à plan incliné. En conclusion, les déformations thermiques des patins de la butée ou de la glissière sont établies comme le principal mécanisme de création de pression dans les butées à surfaces parallèles. En outre, elles contribuent de manière significative aux performances TEHD des butées texturées et revêtues. Au contraire, sur les butées à poche et à plan incliné, les déformations thermiques sont d'une importance négligeable, même à des charges et des températures de fonctionnement élevées
The present Thesis investigates the effects of thermal deformations on the performance of fixed-pad thrust bearings operating under high loads and temperatures. The presented work consists of two main parts. Firstly, in order to identify the mechanisms of pressure build-up in parallel surface thrust bearings, the different theories proposed in the scientific literature have been evaluated. To this end, a CFD-based thermoelastohydrodynamic (TEHD) model has been generated, accounting for all the physical phenomena of the lubricant, of the solid domains and their interaction, which have been suggested in the literature as phenomena contributing to the pressure build-up mechanism of the parallel thrust bearing. The importance of each theory has been quantified and a final modelling approach has been proposed, for accurately evaluating the performance of a parallel thrust bearing. Furthermore, the generated model has been validated against experimental results of the literature. The second part of the Thesis utilises the previously proposed modelling approach to evaluate contemporary designs of thrust bearings, such as textured, coated, pocket and tapered-land bearings. In conclusion, the thermal deformations of the bearing pad are established as the main pressure build-up mechanism in parallel thrust bearings. Moreover, they contribute significantly to the TEHD performance of textured and coated bearings. Contrariwise, on pocket and tapered-land bearings, the thermal deformations are of negligible importance, even at high loads and operating temperatures

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Žatko, Miroslav. "Výpočtová analýza dynamických vlastností axiálních ložisek". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229361.

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This master´s thesis solves the problem of stationary viscous flow of incompressible fluids in thin layers of fluid film lubrication in fixed pad thrust bearings. The parametric computational model of oil domain was created for investigation the distribution of pressure, velocity and thermal fields together with the determination of the basic parameters as axial force, heating up and friction loss. Subsequently this model was applied for investigation influence of uneven bearing clearance. The problem task was solved by final volume method in Ansys CFX 12.0 software.

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Aggarwal, Shipra. "Studies with micro-textured sector shape pad thrust bearings". Thesis, 2017. http://localhost:8080/iit/handle/2074/7485.

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Wang, Yan-Hsin, i 王彥欣. "Design and characteristic analysis of high speed spindle aerostatic circular double pad thrust bearings". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/46126537013464007358.

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碩士
國立彰化師範大學
工業教育學系
89
The purpose of this paper is to make an investigation on the circular aerostatic thrust bearing with grooves and with different diameters presented by describing numerical methods in which Reynolds’ equation is solved in finite element form and on the other way the resistance network method (R.N.M.) based on the concept of flow continuation is obtained. The theoretical model developed is capable of calculating the pressure distribution in the gas-lubricated film and the load-carrying capacity as a separating force. Beside, to analyze the behavior on double-pad thrust bearing with eight restrictors for the high-speed spindle, and to estimate the pressure distribution in considered thrust bearing, numerical calculations were presented by the R.N.M. based on the concept of flow continuation. The coincidence of results derived from the R.N.M. and the F.D.M. based on the Reynolds’ equation has been proved. Finally, the aerodynamic effect caused by the high rotating speed of the spindle will be taken into account. The characteristic of load capacity is influenced by the spindle weight and the bearing inclination.

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Chaturvedi, Kaushal kishore. "Deformation and heat transfer effects in conventional and water-cooled spring-supported tilting-pad thrust bearings". Thesis, 1994. http://localhost:8080/xmlui/handle/12345678/4487.

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Części książek na temat "Shape pad thrust bearings"

Dadouche, Azzedine, Scan M. DeCamillo i Michel Fillon. "Hydrodynamic Tilting-Pad Thrust Bearings". W Encyclopedia of Tribology, 1757–65. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_49.

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Chatterton, Steven, Paolo Pennacchi i Andrea Vania. "Performances Degradation of Tilting-Pad Thrust Bearings Due to Electrical Pitting". W Proceedings of the 9th IFToMM International Conference on Rotor Dynamics, 981–94. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-06590-8_80.

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"Profiled pad thrust bearings". W Bearings, 75–79. Elsevier, 1993. http://dx.doi.org/10.1016/b978-1-4831-3549-6.50020-6.

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"Tilting pad thrust bearings". W Bearings, 80–85. Elsevier, 1993. http://dx.doi.org/10.1016/b978-1-4831-3549-6.50021-8.

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"Profiled pad thrust bearings". W Tribology Handbook, A16.1—A16.5. Elsevier, 1995. http://dx.doi.org/10.1016/b978-075061198-5/50017-5.

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"Tilting pad thrust bearings". W Tribology Handbook, A17.1—A17.6. Elsevier, 1995. http://dx.doi.org/10.1016/b978-075061198-5/50018-7.

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Glavatskih, S. B. "Tilting pad thrust bearings". W Tribology Series, 379–90. Elsevier, 2003. http://dx.doi.org/10.1016/s0167-8922(03)80151-7.

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"Hydrodynamic Fixed-Pad Thrust Bearings". W Encyclopedia of Tribology, 1729. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_100692.

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"Tilting Pad (Large) Thrust Bearings". W Encyclopedia of Tribology, 3691. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_101429.

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"Hydrodynamic Tilting-Pad Thrust Bearings for Hydrogenerators". W Encyclopedia of Tribology, 1765. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_100702.

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Streszczenia konferencji na temat "Shape pad thrust bearings"

Najar, F. A., i G. A. Harmain. "Novel Approach Towards Thrust Bearing Pad Cooling". W ASME 2014 Gas Turbine India Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gtindia2014-8165.

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The present paper analyzes the thermal effect on a sector shaped pad extensively used in thrust bearings which supports the heavy axial loads. Large hydro-generator thrust bearings are susceptible to too much thermo-elastic deformation when oil film thickness is subjected to high pressure and temperature which can even lead to the bearing failure. So as a remedy, this study is an effort towards reducing the oil film temperature by incorporating a suitable cooling treatment. The cooling circuit, in this study, essentially follows a path of hot spots observed by solving Reynolds equation, energy equation and generalized Fourier heat conduction equation. The numerical scheme followed during investigation is finite difference method (FDM). The water circuit developed is just beneath the Babbitt lining of the pads. It has been observed that overall temperature has reduced significantly as compared to traditional cooling systems.

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Hemmi, Makoto, Koushu Hagiya, Katsuhisa Ichisawa i Sukeyuki Fujita. "Computation of Thermal Deformation of Thrust Bearing Pad Concerning the Convection by Non-Uniform Oil Flow". W World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63327.

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Tilting-pad thrust bearings are used to support the loads of large rotating machinery, such as water turbine generators. When such machines are in operation, thermal deformation is so extensive that it is comparable to deformation caused by the pressure of the oil film, and it influences the bearing’s performance. So, the temperature distribution in the pad, which determines the thermal deformation, should be calculated correctly. This requires precise estimation of the convection by the ambient oil at the pad’s surfaces, but the complexity of the pad’s shape and ambient oil flow of oil around it makes this estimation difficult. Using CFD (Computational Fluid Dynamics) software, we computed the temperature distribution in the pad by solving the heat transfer in the pad, in the oil and interfaces of them simultaneously. The thermal and stress deformation were then calculated by the FEM code and is used in oil film analysis to determine the characteristics of the bearing. Comparing its results with the experimental ones validated the computational process.

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Fu, Gen, i Alexandrina Untaroiu. "An Optimum Design Approach for Textured Thrust Bearing With Elliptical-Shape Dimples Using CFD and DOE Including Cavitation". W ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66971.

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Surface texturing has been used to enhance contact performance for decades since 1960s. Surface structures can tremendously change the friction coefficient of the contact surface. These structures have been widely used in bearings and seals. According to previous studies, textured thrust bearings provide more loading capacity than non-textured bearings. Compared to tapered and step bearings, the dimples can also reduce the friction torque. However, most previous optimization efforts for texturing geometry were focused on rectangular dimples and employed Reynolds equation. Limited studies have been done to investigate the effects of partially textured thrust bearings with elliptical dimples. This study proposes a new optimization approach to find the optimal partially texture geometry with elliptical dimples, which maximize the loading capacity and minimize the friction torque. In this study, a 3D computational fluid dynamics model for a parallel sector-pad thrust bearing is built using ANSYS CFX software instead of solving Reynolds equation with simplified field assumptions. Only one sector of the thrust bearing is modeled. Mass conserving cavitation model is used to simulate the cavitation region inside the dimples. Energy equation for Newtonian flow is also solved. Realistic boundary conditions are applied. The results of the model are validated by the experimental data from the literature. Based on this model, the flow pattern and pressure distribution inside the dimples are analyzed. Then, the geometry of elliptical dimple is parameterized and analyzed using the method of design of experiments (DOE). In this study, all the dimples have identical geometry. The selected geometry parameters include the length of major axis, the length of minor axis, dimple depth, circumferential space between two dimples, radial space between two dimples, radial extend and circumferential extend. The design space is sampled using central composite method. A temperature threshold is set to exclude the design points which result in high temperatures. A quadratic response surface model is created based on the results of the DOE process. Next, a multi-objective optimization scheme is used to find the optimal texture structure with the load force and friction torque set as objective functions. The results show that the shape of dimples has a crucial effect on the performance of the textured thrust bearings. This optimization approach proposed is expected to be useful in typical texture design process of thrust bearing.

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Srikanth, D. V. "Oil Film Angular Stiffness Determination in a Hydroelectric Tilting Pad Thrust Bearing". W STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41134.

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Tilting pad thrust bearings are designed to transfer high axial loads from rotating shafts to the static support structure. In the present paper, formulation of Reynolds’ equation for the bearing is done in two dimensions (planar). A finite difference method is used to convert the terms of the Reynolds’ equation in to a set of simultaneous linear algebraic equations. A solution procedure for finding value of the pressure in the oil film is described. Numerical integration of the pressure values gives the load distribution. Subsequently, the study of angular stiffness of the film is done by varying the value of the oil film thickness and calculating torques at three different film shapes 1, 2 & 3 of the pad. The angular stiffness, differential displacement and load pertaining to the 3-2 pair are calculated for 0.5%–20% variation of ho. The results obtained show that the values of Kt* and K* converge asymptotically.

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Untaroiu, Alexandrina, i Gen Fu. "Surrogate Model Based Optimization for Chevron Foil Thrust Bearing". W ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90228.

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Abstract Gas foil thrust bearings have been utilized in high speed lightweight machines for many decades. These bearings are environment-friendly and capable of withstanding extreme conditions. However, there are also some challenges for foil thrust bearings at high speed conditions, such as insufficient heat dissipation and thermal management. The heat generated by viscous shearing continues to raise the temperature inside the gas film and may cause failures. Among all the methods to enhance heat dissipation, a promising passive thermal management method is modifying the top foil’s trailing edge shape. This modification will enhance the air mixing in between the bearing pads. The aim of this study is to identify the optimal design of the top foil trailing edge shape and provide a guideline for future bearing design. A 3-D computational fluid dynamics (CFD) model for a thrust foil bearing was created using ANSYS-CFX software. The trailing edge of the top foil was modified to a chevron shape. A sensitivity study was conducted to investigate the connection between the top foil trailing edge shape and the thermal conditions in the gas film. The maximum temperature inside the air gas film is selected as the output. The design of experiments (DOE) technique was used to generate the sampling points. A surrogate model was generated based on the output data by using the neural network method. The surrogate model was used together with a genetic multi-objective algorithm to minimize the maximal temperature inside the gas film and maximize the load carrying capacity. The optimal design was then compared with the baseline model. Results suggest the optimized trailing edge shape is capable of reducing the temperature inside the gas film. This optimal design approach can be used for improvements of chevron foil thrust bearing design.

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Bavassano, Francesco, Marco Mantero, Riccardo Traverso, Richard Livermore-Hardy i Barry Blair. "A System Integration Approach for Heavy-Duty Gas Turbine Upgrades Using Improved Rotor Thrust Predictions and Application of Advanced Thrust Bearing Designs". W ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63647.

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The progressive upgrading of heavy-duty gas turbines, aimed at increased performance, can ultimately introduce more onerous operating conditions, to the point that original design limits can be approached. An increased gas turbine pressure ratio together with compression and expansion line adjustments can directly affect the rotor axial thrust. Other than the individual forces acting on the rotor, a key component to be taken into account is the fluid film thrust bearing, which should assure safe and reliable operation during the worst case operating conditions. Typically, such bearings are designed with large safety margins, yet it is possible that the new and more challenging conditions require a bearing capability upgrade, especially when field retrofit needs pose additional constraints. A succession of performance upgrades have been carried out on Ansaldo Energia’s AE94.2 E-Class GT. An accurate understanding of the thrust-related phenomena proved necessary and drove improvements in the thrust bearing design along with hardware adjustments to lower the rotor thrust. This paper addresses calculations and experimental arrangements for the rotor axial thrust evaluation on the aforementioned GT and considers both the matters related to the secondary air system for the thrust generation and the mechanical/functional matters for the bearing upgrade. It is shown that issues such as uneven load sharing across the thrust bearing, or the variability of rotor thrust from engine to engine within the fleet, strongly affect the maximum thrust assessment and thus the requirements used in the process of selecting a suitable bearing. A predictive calculation method is described considering the main thrust contributions. Field experimental setups and main observations are reported. Measurements have been carried out using thermocouples and load cells placed on many of the thrust bearing pads. Moreover, the engine cavities carrying the highest and/or the most uncertain thrust share have been instrumented and characterized by pressure sensors. The development of an upgraded thrust bearing is finally depicted through the main issues addressed, such as improved thrust pad lining material, increased load sharing efficiency and enlarged thrust bearing active surface area. Waukesha Bearings test results on the upgraded lining material, a high-tin aluminium alloy are reported as well. A multidisciplinary approach is presented as necessary to manage the crucial challenge of improving the thrust balancing system, especially in the case of a formerly designed engine which receives a powerful upgrade.

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Kettleborough, C. F. "Starting Phenomena of Tilting Pad Bearings". W ASME 2001 Engineering Technology Conference on Energy. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/etce2001-17169.

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Abstract The starting of large thrust bearings in turbines is one of the most critical points in their operation as a pressure carrying oil film must be generated from initial conditions of load and zero relative velocity between the two surfaces. A force equal and opposite to the applied load must be produced before the surfaces separate. It is the purpose of this paper to discuss the origin and formation of this force. The results show that lapped and ground surfaces have inefficient lifting characteristics as compared with surfaces having irregularities on the surface of 1/20 mil and greater. In general, surface oil pockets have an important influence on the starting behavior of tilting pad bearings; without these oil pockets it is doubtful if the two bearing surfaces would part.

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Cangioli, Filippo, Alex-Florian Cristea, Richard Livermore-Hardy i Yujiao Tao. "The Effect of Pad Materials on the Limits of Operation for Tilting Pad Thrust Bearings". W ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-82655.

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Abstract The scope of this paper is to define the effect of pad materials on the limits of operation of tilting pad thrust bearings. In this paper, the Authors extend the work done by Martin on the limits of operation for steel/whitemetal bearings to other pad backing and lining materials widely used and accepted in the turbomachinery industry, such us, AlSn and PEEK for the lining and CuCr for the backing of the pad. This work has been achieved following a comprehensive experimental characterization of several different tilting pad thrust bearing sizes, with multiple pad backing/lining material options, over a wide range of speeds and loads. The Authors developed and validated a state-of-the-art thermo-elasto-hydrodynamic numerical model to predict the performance of tilting pad thrust bearings and define the limiting envelope. The numerical model couples the generalized Reynolds equation with a 3D heat transfer and structural-mechanics model of the pad, which allows to consider the effect of the pad material properties on the bearing performance. Experimental data along with numerical results reveal the effect that materials have on the limits of operation for a tilting pad thrust bearings for safe operating load and speed in hydrodynamic lubrication.

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Rimpel, Aaron M., Giuseppe Vannini i Jongsoo Kim. "A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings". W ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57665.

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A high speed gas bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas bearings being developed for an oil-free turboexpander. The radial bearings tested in this paper were tilting pad journal bearings with radial compliance features that allow the bearing bore to increase to accommodate shaft growth, and the thrust bearings were a spiral groove type with axial compliance features. The thrust bearing accounts for over 90% of the combined bearing power consumption, which has a cubic relationship with speed and increases with case pressure. Radial bearing circumferential pad temperature gradients increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady state bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the thrust bearing showed a significant increase in temperature with higher case pressure. The thrust bearings were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been proposed to better understand the thrust bearing thermal behavior and to improve the thrust bearing design. Finally, the radial bearings tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas bearings tested in the literature.

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Dousti, Saeid, Paul Allaire, Jianming Cao, Bradley Nichols i Timothy Dimond. "A Numerical Thermohydrodynamic Study of Fixed Pad Oil Lubricated Thrust Bearings". W ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91596.

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Abstract Hydrodynamic thrust bearings are vital components of rotating machinery and often undergo high axial loads and temperatures. High loads and the consequent shear heating result in high temperature development and viscosity drop of the lubricant. This phenomenon is captured in the solution of a three dimensional energy equation problem. The inlet flow temperature via a groove mixing model and its interaction with outflow from the previous pad is also included in the analysis. Traditionally, capturing the heat conduction at the lubricant solid interfaces in the energy solution for the fixed pad, lubricant, and rotating disk (runner) have faced significant convergence problems. In this study, an integrated method is proposed to remedy this issue. The effects of various model features on the computed results are investigated.

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