Artykuły w czasopismach: „Lubricated journal bearings”

1

Gao, Geng Yuan, Zhong Wei Yin, Dan Jiang i Xiu Li Zhang. "Researches on Friction Performance of Water-Lubricated Polymer Composite Journal Bearings Based on Experiments". Applied Mechanics and Materials 711 (grudzień 2014): 57–60. http://dx.doi.org/10.4028/www.scientific.net/amm.711.57.

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A composite which is PTFE as a matrix with PEEK and carbon fiber as fillers is developed to fabricate the bush of water-lubricated journal bearings. The bush is fabricated with a new structure that a relatively large straight groove is opened in its upper part. A water-lubricated journal bearing made up of the bush and a steel sleeve is studied using purposed-built test rig. It is shown that the test bearing operates under hydrodynamic lubrication for almost all of the given conditions. The composite developed in the work is a promising material for water-lubricated journal bearings, and the new structure can be well used in water-lubricated journal bearings.

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Lv, Fangrui, Chunxiao Jiao, Qian Jia i Kang Xia. "Influence of Structural and Operating Parameters on Lubrication Performance of Water-Lubricated Polymer Bearing with Journal Misalignment". Lubricants 10, nr 12 (28.11.2022): 336. http://dx.doi.org/10.3390/lubricants10120336.

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Marine water-lubricated polymer bearings support the propeller shaft that stretches out of the ship. The bending deformation of propeller shaft often leads to journal misalignment, significantly impacting the bearing performance. In this paper, a mixed lubrication model for water-lubricated polymer bearing is established considering the effect of journal misalignment, liner elastic deformation, and local turbulence. The influence of key structural and operating parameters on the performance of water-lubricated bearing with journal misalignment is investigated. The results show that the journal misalignment significantly reduces the load-carrying capacity, deteriorates the bearing tribological characteristics, and may cause different axial sections of the bearing to be in different lubrication regimes. Compared with aligned bearings, increasing the length–diameter ratio to improve the load-carrying capacity is significantly weakened for misaligned bearings. Increasing the liner thickness and the load improves axial uniformity of pressure distribution of misaligned bearings. A relatively large clearance ratio decreases the load-carrying capacity and increases the friction coefficient of bearings in the mixed lubrication regime.

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Chen, Pingwei, Tong Wang, Wensheng Ma, Jie Chen i Rui Cao. "Rotordynamic characteristic of water lubricated plain journal bearing under transient load". Journal of Physics: Conference Series 2280, nr 1 (1.06.2022): 012046. http://dx.doi.org/10.1088/1742-6596/2280/1/012046.

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Abstract Transient startup operating parameter has a serious influence on the stability of water-lubricated bearings. In this study, CFD method was used to predict the rotordynamic coefficients of water lubricated bearings under transient loads. The stiffness and damping coefficients versus transient time for water-lubricated bearings are given. The stiffness and damping coefficients versus different transient loads for water-lubricated bearings are also given. The results show that the stiffness and damping coefficients will increase rapidly in a very short time. With the increase of impact time, both of them come to a steady value. With the increase of impact load, the direct stiffness and the direct damping coefficients of water lubricated bearing will increase. The value of cross-coupling stiffness and the cross-coupling damping coefficients will decrease.

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Rho, B.-H., D.-G. Kim i K.-W. Kim. "Noise analysis of oil-lubricated journal bearings". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 217, nr 3 (1.03.2003): 365–71. http://dx.doi.org/10.1243/095440603762870027.

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The objective of the paper is to provide a procedure for calculating the noise of oil-lubricated journal bearings. In order to obtain acoustical properties of the bearing, a non-linear analysis including rotor imbalance is performed for a rotor-bearing system. Sound pressure levels of the bearing are obtained through frequency analysis of pressure fluctuations calculated from the non-linear analysis using a transmission theory of plane waves. Results show that the sound pressure level of the bearing increases with the rotational speed of the rotor, although the whirl amplitude of the rotor is decreased at high speed. The noise-estimating procedure presented in the paper could be an aid in the evaluation and understanding of acoustical properties of oil-lubricated journal bearings.

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Ma, Can, Qichao Yang, Xiaohang Sun, Kelong Zhang i Liansheng Li. "Performance Analysis of Externally Pressurized Gas Journal Bearing Lubricated with Vapor of R134a in Centrifugal Compressor". Processes 10, nr 10 (13.10.2022): 2067. http://dx.doi.org/10.3390/pr10102067.

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The performance of an externally pressurized gas journal bearing lubricated with R134a vapor used in an oil-free refrigeration centrifugal compressor is calculated by solving Reynold equations with the finite difference method (CFD). The load capacity, stiffness and mass flow rate of refrigerant vapor under conditions of various operational parameters are obtained and compared with that in air gas bearings. In addition, the influences of the average clearance, eccentricity ratios and supply vapor pressure on the static characteristics of journal bearings are investigated and discussed in detail. It concluded that the optimal operation parameters of gas journal bearings lubricated with R134a vapor are different with air journal bearings. These factors should be considered in the design process of R134a refrigerant vapor gas journal bearings.

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Chetti, B. "Elastohydrodynamic Analysis of an Offset Journal Bearing Lubricated with Couple Stress Fluid". International Journal of Engineering Research in Africa 2 (czerwiec 2010): 53–62. http://dx.doi.org/10.4028/www.scientific.net/jera.2.53.

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This work is an investigation of the performance characteristics of an offset journal bearing lubricated with a fluid with couple stresses taking into consideration the elastic deformation of the liner. The couple stresses might be expected to appear in noticeable magnitudes in liquids containing additives with large molecules. The modified Reynolds equation has been solved using the finite difference method. Load carrying capacity, attitude angle, side leakage and friction coefficients are determined for various values of couple stress parameter of a rigid and deformable bearing. It is found that, the static characteristics of journal bearings lubricated with couple stress fluids are improved compared to journal bearings lubricated with Newtonian fluids. It is concluded that, the elastic deformation of the bearing has significant influence on the bearing characteristics.

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Wang, Yanzhen, Zhongwei Yin, Dan Jiang, Gengyuan Gao i Xiuli Zhang. "Study of the lubrication performance of water-lubricated journal bearings with CFD and FSI method". Industrial Lubrication and Tribology 68, nr 3 (11.04.2016): 341–48. http://dx.doi.org/10.1108/ilt-04-2015-0053.

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Purpose Water lubrication is significant for its environmental friendliness. Composite journal bearing is liable to deform for the huge pressure of water film. This paper aims to study the influence of elastic deformation on how lubrication functions in water-lubricated journal bearings and to provide references for designing composite journal bearings. Design/methodology/approach The combination of computational fluid dynamics and fluid-structure interaction is adopted in this paper to study the lubrication performance of water-lubricated compliant journal bearings. The influences of elasticity modulus and Poisson’s ratio on load-carrying capacity and elastic deformation are studied for different rotational speeds. Predictions in this work are compared with the published experimental results, and the present work agrees well with the experimental results. Findings A reference whether elastic deformation should be considered for composite journal bearings is proposed under different working conditions. Besides, a reference to determine water-lubricated plain journal bearings dimensions under different loads and rotational speeds is developed with the effect of both elastic deformation and cavitation being accounted. Originality/value The present research provides references as to whether elastic deformation should be considered in operation and to determine compliant journal bearings’ dimensions in the design process.

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Zhao, Zhiming, i Rui Zhang. "Theoretical and experimental analysis of a water-lubricated rubber journal bearing with a large aspect ratio". Industrial Lubrication and Tribology 72, nr 6 (2.03.2020): 797–803. http://dx.doi.org/10.1108/ilt-10-2019-0440.

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Purpose The hydrodynamic characteristics of liquid film for bearings, especially water-lubricated bearings with a large length-to-diameter ratio, affect the dynamics behavior of rotor bearing systems. The purpose of this study is to carry out theoretical analysis and experiments to determine the hydrodynamic characteristics of water-lubricated journal bearings. Design/methodology/approach The finite difference method is adopted for the simulation of the characteristics of water-lubricated bearings. The comparison results between water-lubricated bearings with and without grooves, as well as with and without the consideration of the effects of rubber deformation, are presented. The test bearings, test bench, and monitoring system, especially the force exciter for the bearing experiment, are presented. Dynamic coefficient identification verification experiments were performed in different working situations. The obtained results include the calibration of magnetic force, two kinds of excitation, vibration data of the rotor system and dynamic coefficients. Findings The theoretical results demonstrate that the hydrodynamic effect was obvious when the speed was increased and that the water film had improved capability at a working speed of 1800 rpm. The identification results reveal the lubrication situation of the test bearing under low-speed and high-load conditions. Moreover, it was found that the liquid film was not continuous at low speeds. Originality/value The theoretical results can lead to the enhancement of the design level of water-lubricated rubber journal bearings with a large aspect ratio. The experimental results can lead to the improvement of the dynamic behavior design of rotor systems supported using water-lubricated bearings with a large length-to-diameter ratio.

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Zhang, Yong Fang, Xiao Lei Shi, Yan Jun Lu i Lie Yu. "Numerical Analysis Method and Bifurcation of Gas-Lubricated Journal Bearing-Rotor System with Gyroscopic Effect". Advanced Materials Research 230-232 (maj 2011): 197–201. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.197.

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Based on the nonlinear theory, the unbalanced responses of the gas-lubricated journal bearing-rotor system are investigated. A time-dependent mathematical model is established to describe the pressure distribution of gas-lubricated journal bearing with nonlinearity. The rigid rotor with gyroscopic effect supported by self-acting gas journal bearing with three axial grooves is modeled. The differential transformation method is employed to solve the time-dependent gas-lubricated Reynolds equation, and the dynamic motion equation is solved by Newmark-β method. The unbalanced responses of the rotor system supported by finite gas-lubricated journal bearings are analyzed by bifurcation diagram, orbit diagram, Poincaré map. The numerical results reveal periodic, period-4 motion of nonlinear behaviors of the system.

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Gengyuan, Gao, Yin Zhongwei, Jiang Dan i Zhang Xiuli. "CFD analysis of load-carrying capacity of hydrodynamic lubrication on a water-lubricated journal bearing". Industrial Lubrication and Tribology 67, nr 1 (9.02.2015): 30–37. http://dx.doi.org/10.1108/ilt-03-2013-0028.

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Purpose – The purpose of this paper is to improve hydrodynamic load-carrying capacity of a water-lubricated journal bearing by a new bush structure. Water-lubricated bearing is becoming more and more popular since it is environmentally friendly and saves energy. However, contrary to oil and grease-lubricated bearings, water-lubricated bearing is limited in many situations due to its low hydrodynamic load-carrying capacity. Design/methodology/approach – The present article proposes a new bearing bush, with a transition-arc structure, which is favorable for increasing hydrodynamic load-carrying capacity. Hydrodynamic load-carrying capacity was calculated by means of three-dimensional computational fluid dynamics (3-D CFD) analysis. Several variants of a journal bearing with a transition-arc structure of different dimensions are analyzed, while the radial clearance of the bearing, eccentricity ratio and the velocity of the journal remain unchanged. Findings – The results show that obvious changes are found in hydrodynamic load-carrying capacity of a water-lubricated journal bearing. For different width over diameter (L/D) bearing ratios, the relationship between hydrodynamic load-carrying capacity and the magnitude of the transition-arc structure dimension is researched. Originality/value – The research presented here leads to a design reference guideline that could be used by the designer engineer to design smart journal bearings for improving the hydrodynamic load-carrying capacity.

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Piątkowska, Ewa. "Influence of solid particle contamination on the wear process in water lubricated marine strut bearings with NBR and PTFE bushes". Polish Maritime Research 28, nr 4 (1.12.2021): 167–78. http://dx.doi.org/10.2478/pomr-2021-0059.

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Abstract This paper reports on a study of the influence of solid particle contamination on the wear process in water-lubricated slide bearings (steel-acrylonitrile-butadiene rubber (NBR) and steel-polytetrafluoroethylene (PTFE)). To compare the wear of the shaft journal and bushes (NBR and PTFE) when lubricated with fresh water and contaminated water, an experiment was carried out to identify key factors that influence the state of wear of slide bearing. The amount of wear was checked by means of geometric structure measurements on the journals, namely, roughness profile measurements using both a contact profilometer and an optical microscope. The obtained results enabled correlations between the material comprising the sliding sleeve, roughness of the journals and contamination inside the water-lubricated slide bearings.

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Khan, M. Z., i T. A. Stolarski. "Dynamic Performance of Oil-Lubricated Helical Groove Journal Bearings". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 208, nr 1 (marzec 1994): 65–73. http://dx.doi.org/10.1243/pime_proc_1994_208_350_02.

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The provision of helical grooves on the surface of a plain journal bearing can, in principle, improve the stability of a rotor-bearing system. The improvement, however, depends on the arrangement of the grooves along the axial length of the bearing. In order to verify this, three types of helical groove bearing with different groove arrangements and a reference plain journal bearing were studied. The bearings were studied in a specially designed test rig. A computer model was also developed to predict the performance of the bearings studied. The experimental and theoretical results produced during the course of the studies show that at the expense of a reduced load capacity the helical groove bearings are more stable, particularly at low eccentricity ratios. For a given eccentricity ratio and speed the symmetrical bearing operates at higher temperature and with greater power losses than the other three bearings tested. At the same eccentricity ratio and speed, the asymmetrical bearing runs at about the same temperature as the plain journal bearing.

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Zhang, Xiu Li, Zhong Wei Yin, Dan Jiang i Geng Yuan Gao. "Comparison of the Lubrication Performances of Water-Lubricated and Oil-Lubricated Plain Journal Bearings". Applied Mechanics and Materials 711 (grudzień 2014): 27–30. http://dx.doi.org/10.4028/www.scientific.net/amm.711.27.

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Water-lubricated bearings have attracted increasing attention in recent years because of their environmental sustainability, simplified design, low cost, good cooling performance and low coefficient of friction. To show the characteristic of water lubrication more clearly, this paper quantitatively compares the lubrication performances of water-lubrication plain journal bearing and oil-lubricated plain journal bearing using CFD method. Bearing length, friction coefficients, power losses and temperature rises are obtained under the same working condition. Results show that water-lubricated bearing needs to be 3.4 times longer than oil-lubricated bearing, but its friction coefficient and power loss are only 11.7% of those of oil-lubricated bearing and its maximum temperature rise is less than 2 K, much lower than 96.76 K corresponding to oil lubrication.

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Feng, Huihui, i Shuyun Jiang. "Dynamics of a motorized spindle supported on water-lubricated bearings". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, nr 3 (8.08.2016): 459–72. http://dx.doi.org/10.1177/0954406215616653.

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The purpose of this paper is to investigate the dynamic performances of a motorized spindle supported on water-lubricated bearings. A modified transfer matrix method considering both of the translational and tilting dynamic coefficients of the bearings is established. The turbulent Reynolds equation is adopted and numerically solved by the perturbation method and the finite difference method, and the dynamic characteristics of the water-lubricated journal bearings are obtained; the effects of the eccentricity ratio, tilting angle, and the rotational speed on the dynamic coefficients of the water-lubricated journal bearings are analyzed. The critical speed, the dynamic stiffness of spindle nose, and unbalance response of the motorized spindle are investigated. Finally, a comparative study of rotor dynamic behaviors between the 32- and the eight-coefficient bearing models is conducted. The numerical predictions obtained by the 32-coefficient bearing models correlate well with the experimental values available in the literature.

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Feng, Hui Hui, Chun Dong Xu i Feng Feng Wang. "Combined Influence of Misalignment and Orifice Diameter on the Static Performances of Hydrostatic, Water-Lubricated Journal Bearings". Applied Mechanics and Materials 607 (lipiec 2014): 608–11. http://dx.doi.org/10.4028/www.scientific.net/amm.607.608.

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The water-lubricated bearings have gained an increasing focus to overcome the disadvantages of the oil film bearings and gas bearings. In this paper, the influences of orifice diameter in aligned and misaligned conditions on the static performance of two hydrostatic, four-recess, water-lubricated journal bearings used to support a rigid rotor, are investigated. The steady Reynolds equation for the journal bearing for the turbulent bulk flow and the film thickness expression considering tilting angles are used and numerically solved by finite difference method. Results demonstrate that the static performances, such as the quality, power loss and temperature rise are affected by the tilting angles, orifice diameter to some degree.

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NIKOLAKOPOULOS, P. G., i C. A. PAPADOPOULOS. "HIGH SPEED JOURNAL BEARINGS LUBRICATED WITH ELECTRO-RHEOLOGICAL FLUIDS: AN EXPERIMENTAL INVESTIGATION". International Journal of Modern Physics B 10, nr 23n24 (30.10.1996): 3045–55. http://dx.doi.org/10.1142/s0217979296001495.

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It is well known that the imposition of an electric field on an Electro-Rheological (ER) fluid alters the viscosity and as a consequence the f flow properties of the f fluid. If such a fluid is used to lubricate a journal bearing system, it is expected that the imposition of an electric field between the rotor and the stator will cause the alteration of the dynamic properties of the journal bearing. For the present, it has been proved that this is valid only for low speeds and high radial clearances of Couette type viscometers. In this paper an experiment in a high speeds (16000 to 65000 s −1) journal bearing with small radial clearance is presented. The experiment performed has showed the phenomenon and has proved that the ER FLUID at high shear rates under constant temperature, follows the Bingham model in realistic bearings. Properties such as wall shear stress, dynamic yield stress relative viscosity are experimentally determined as functions of the electric field, for different particle concentrations and the shear strain rate under constant or free to vary temperature (due to operating conditions, angular velocity, friction). Concluding the ER fluids can be used to create “smart” journal bearings. Vibration controllers can be constructed to control the stability of the ER fluid lubricated bearings.

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Heshmat, H. "Advancements in the Performance of Aerodynamic Foil Journal Bearings: High Speed and Load Capability". Journal of Tribology 116, nr 2 (1.04.1994): 287–94. http://dx.doi.org/10.1115/1.2927211.

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An advanced-design, aerodynamic, air-lubricated foil journal bearing achieved a landmark speed of 2200 cps (132,000 rpm) and a major breakthrough in load performance of 673.5 kPa (97.7 psi). At 20°C (68°F) room temperature, normal ambient pressure, 995 cps (59,700 rpm) rotor speed, and with bearing projected pad area of 1081 mm2 (1.675 in2), the bearing demonstrated a load capacity of 727.8 N (163.6 lb). The bearing also exhibited low heat generation, with about 40°C (104°F) average side leakage temperature rise. For this demonstration, a highspeed spindle utilizing a pair of 35-mm (1.375-in.) bearings and supporting a test rotor with a mass of 1.545 kg (weighing 3.41 lb) and overall length of 211 mm (8.3 in.) was successfully taken to the limiting speed of the test apparatus. This speed was set by the maximum sound velocity (Mach 1) in the spindle’s turbine wheel. The rotor/bearing speed of 4.62 × 106 DN is beyond the capability of any advanced oil-lubricated ball bearings or conventional gas-lubricated bearings. The net result is a highly stable bearing at high operating speed. This paper presents the development of this air-lubricated foil journal bearing, the operational procedures used during testing, test results (dynamic analyses), and load performance characteristics.

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Yang, Xue Bing, Wan Li Xiong, Zhi Quan Hou i Ju Long Yuan. "A Method of Parameters Estimation of Water-Lubricated Hybrid Journal Bearings for Ultra-Precision Machine Tool Spindle". Advanced Materials Research 69-70 (maj 2009): 270–76. http://dx.doi.org/10.4028/www.scientific.net/amr.69-70.270.

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Water-lubricated hybrid journal bearings have been developed to support the ultra-precision machine tool spindles, due to the prominent properties of high load capacity and stiffness, high rotational accuracy, excellent thermal stability, low power consuming and environmental friendliness. Quasi-analytical procedures are deduced to present a relatively easy and rapid method for estimating of the parameters of the water-lubricated hybrid bearings without resorting to complex full numerical calculation. The procedures are based on the lumped resistance method, which have been extended to the situation dominated by the turbulence and inertia effects. The results show good agreement with the full numerical solution, especially when the bearing operating at moderate eccentricities. The procedures can be taken as a real time analytical tool for parametric study and preliminary engineering design of water-lubricated hybrid journal bearings.

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Li, Qiang, Shuo Zhang, Yujun Wang, Weiwei Xu, Zengli Wang i Zhenbo Wang. "Dynamic characteristics of water-lubricated journal bearings". Mechanics & Industry 20, nr 4 (2019): 404. http://dx.doi.org/10.1051/meca/2019037.

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The increasing ecological awareness and stringent requirements for environmental protection have led to the development of water lubricated journal bearings. For the investigation of water-lubricated journal bearings, a new structured mesh movement algorithm for the CFD model is developed and based on this method, the nonlinear transient hydrodynamic force model is established. Then, with consideration of velocity perturbation, a method to determine dynamic coefficients and linear hydrodynamic forces is promoted. After validation of static equilibrium position and stiffness coefficients, a comparative linear and nonlinear hydrodynamic force analysis of multiple grooves water-lubricated journal bearings (MGWJBs) is conducted. The calculation results indicate that the structured mesh movement algorithm is suitable for the dynamic characteristics investigation of water-lubricated journal bearings. And the comparative study shows that there is a considerable difference between the linear and nonlinear hydrodynamic forces of MGWJBs. Further investigation should be carried to evaluate the dynamic responses of rotor supported by MGWJBs under difference force models.

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Lai, Tianwei, Yu Guo, Wei Wang, Yu Wang i Yu Hou. "Development and Application of Integrated Aerodynamic Protuberant Foil Journal and Thrust Bearing in Turboexpander". International Journal of Rotating Machinery 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/8430943.

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Foil bearing provides compliant support and moderate Coulomb friction for rotor-bearing system, which is conducive to stability and reliability of high speed rotating machinery. In this paper, both hydrodynamic lubricated foil journal and foil thrust bearings are applied in a 150 m3·h−1 turboexpander for air separation. In the bearings, protuberant foil is chosen as the supporting subfoil due to its merits of easy fabrication and assembly. Static loading and deflection of the bearings are tested, respectively, before integration into the turboexpander. Afterwards, the loading and deflection curves of the journal and thrust bearings are polynomial fitted using least-square method. Then, performance tests are carried out on the rotor-bearing system, including transient speed-up, high speed, and speed-down processes. In the tests, the turboexpander supported by the hydrodynamic foil bearings operates smoothly with repeatability. Maximal rotor speed of the turboexpander reaches 52000 rpm with hydrodynamic lubricated protuberant foil bearings.

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Bhardwaj, Vivek. "Performance behavior of pocketed journal bearing employing non-newtonian lubricant". Engineering Research Express 3, nr 4 (3.11.2021): 045013. http://dx.doi.org/10.1088/2631-8695/ac3323.

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Abstract This paper reports the improvement in the performance behaviors of non-Newtonian fluid lubricated journal bearings employing a rectangular pocket. Coefficient of friction and load carrying capacity of pocketed and non-pocketed bearings are reported and discussed. In the numerical approach, non-Newtonian behavior of lubricant is simulated employing the power law model. Various cases of bearings having different axial length to diameter ratios [(L/D) in the range 0.5–2.0] are considered. Lubricants of different rheology viz. pseudoplastic, Newtonian and shear thickening were employed for lubricating the bearings. Rheology of lubricant is controlled by varying the power law index n in the range 0.9–1.1. Based on the investigation, it is found that the pocketed bearing yields significantly reduced coefficient of friction and higher load carrying capacity in comparison to the non-pocketed bearing. Also, the performance of pocketed bearing improves with the increase in the power law index. Best performance of the pocketed bearing is observed for the bearing having L/D value of 0.5 at high eccentricity ratio when lubricated with the shear thickening fluid (n=1.1).

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Patel, Dilip C., i Deepak P. Vakharia. "Determination of Friction Coefficient in Floating Bush Bearings by Strain Gauge Method". International Journal of Automation Technology 4, nr 4 (5.07.2010): 389–93. http://dx.doi.org/10.20965/ijat.2010.p0389.

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A floating bush bearing is a kind of journal bearing in which the bushing will float between the journal and bearing. Knowing the frictional coefficient is important for the determination of wear loss and power loss conditions; an appropriate test rig is used to determine friction of floating bush bearings. The frictional coefficient of bearings in dry and lubricated conditions has been examined in experiments.

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Das, Subrata, i Sisir Kumar Guha. "Non-linear stability analysis of micropolar fluid lubricated journal bearings with turbulent effect". Industrial Lubrication and Tribology 71, nr 1 (14.01.2019): 31–39. http://dx.doi.org/10.1108/ilt-07-2017-0212.

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Purpose The purpose of this paper is to investigate the effect of turbulence on the stability characteristics of finite hydrodynamic journal bearing lubricated with micropolar fluid. Design/methodology/approach The non-dimensional transient Reynolds equation has been solved to obtain the non-dimensional pressure field which in turn used to obtain the load carrying capacity of the bearing. The second-order equations of motion applicable for journal bearing system have been solved using fourth-order Runge–Kutta method to obtain the stability characteristics. Findings It has been observed that turbulence has adverse effect on stability and the whirl ratio at laminar flow condition has the lowest value. Practical implications The paper provides the stability characteristics of the finite journal bearing lubricated with micropolar fluid operating in turbulent regime which is very common in practical applications. Originality/value Non-linear stability analysis of micropolar fluid lubricated journal bearing operating in turbulent regime has not been reported in literatures so far. This paper is an effort to address the problem of non-linear stability of journal bearings under micropolar lubrication with turbulent effect. The results obtained provide useful information for designing the journal bearing system for high speed applications.

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Lin, J. R., T. C. Hung i C. H. Lin. "Linear Stability Analysis of Journal Bearings Lubricated With a Non-Newtonian Rabinowitsch Fluid". Journal of Mechanics 35, nr 1 (28.06.2017): 107–12. http://dx.doi.org/10.1017/jmech.2017.48.

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AbstractThe linear stability boundaries of journal bearings lubricated with a non-Newtonian fluid have been investigated in this paper. Based on the Rabinowitsch fluid model, a non-Newtonian dynamic Reynolds equation for journal bearings is derived and then applied to analyze the linear dynamic characteristics of short journal bearings. Comparing with the Newtonian-lubricant case, the non-Newtonian rheology of dilatant lubricants provides a larger area of linearly stable region. However, the non-Newtonian properties of pseudo-plastic lubricants results in a reverse trend for the short journal bearing.

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Czaban, Adam. "CFD Analysis of Hydrodynamic Pressure Distribution in Non-Newtonian Oil in Journal Bearing Lubrication Gap". Solid State Phenomena 220-221 (styczeń 2015): 37–42. http://dx.doi.org/10.4028/www.scientific.net/ssp.220-221.37.

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This paper presents the results of CFD analysis of the hydrodynamic pressure distribution in slide journal bearings lubricated by non-Newtonian oil. It was assumed that the oil shear stress varies from shear rate according to the Ostwald–de Waele relationship (power law lubricant). The comparison was related to bearings differences only in properties of lubricating oil – Newtonian and non-Newtonian properties; other parameters for both in each case were the same. The Tables show relative decrease of the maximum hydrodynamic pressure value and bearing lift capacity according to the bearing lubricated with Newtonian oil, for different values of bearing relative eccentricity.

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Qiang, Mingchen, Qi Zhao, Shaohang Yan, Xue Liu, Yu Hou i Tianwei Lai. "Performance Prediction of High-Speed Hydrogen Gas-Lubricated Herringbone Grooved Journal Bearing". Applied Sciences 12, nr 13 (24.06.2022): 6432. http://dx.doi.org/10.3390/app12136432.

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The liquefaction of hydrogen is considered to be a crucial process in the large-scale utilization of hydrogen energy. In hydrogen liquefaction, hydrogen turbo-expander is a key refrigerating machine for high liquefaction efficiency. Performance of the turbo-expander is directly affected by the hydrogen gas bearings. To obtain a deep understanding of the performance characteristics of hydrogen gas bearings, the static and dynamic characteristics of herringbone grooved journal bearings under hydrogen and other lubricating gases were numerically calculated and compared. The bearing load capacity and critical mass of hydrogen gas bearings were slightly lower than those of helium-, air- and nitrogen-lubricated bearings. To improve the performance of the hydrogen gas bearings used in high-speed turbo-machinery, the influence of working conditions was analyzed. It is found that the load capacity of hydrogen gas bearings can be improved by increasing the ambient pressure, reducing the gas film clearance, and raising the bearing eccentricity ratio. Meanwhile, the critical mass increases, and the bearing dynamic stability is enhanced.

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Khonsari, M. M., i V. Esfahanian. "Thermohydrodynamic Analysis of Solid-Liquid Lubricated Journal Bearings". Journal of Tribology 110, nr 2 (1.04.1988): 367–74. http://dx.doi.org/10.1115/1.3261635.

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Thermohydrodynamic theory is extended to include the effect of solid particles in hydrodynamically lubricated journal bearings. Appropriate governing equations and boundary conditions are derived for the fluid flow and heat transfer processes taking place in a finite journal bearing. A general computer program is developed to numerically solve the governing equations. Results are provided for biphase lubricants containing oil with molybdenum disulfide and polytetrafluoroethylene particles. The computational results are in good agreement with experimental findings. The results indicate that the bearing temperature field is affected significantly by the presence of particles in oil. Moreover, it is found that inclusion of particles in the lubricant results in a higher coefficient of friction in the mid-range of the Sommerfeld number compared to that of the clean oil.

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Feng, Hui Hui. "Dynamic Characteristics of a Rigid Spindle Supported by Water-Lubricated Bearings". Applied Mechanics and Materials 401-403 (wrzesień 2013): 121–24. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.121.

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In this paper, a rigid spindle supported by two identical water-lubricated journal bearings is proposed. The dynamic equations of motion are presented to predicate the performance of the spindle. Under the assumption of linearity, the responses of the rotor excited by constant external force and unbalance force are comprehensively discussed by the fourth Runge-Kutta method. To analyze the static and dynamic characteristics of the water-lubricated bearings, the bulk flow turbulent theory is used and numerically solved by finite difference method. Results of this investigation contribute a better understanding of the performance of a water-lubricated bearing-rotor system.

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Heshmat, H., i D. Brewe. "Performance of Powder-Lubricated Journal Bearings With MoS2 Powder: Experimental Study of Thermal Phenomena". Journal of Tribology 117, nr 3 (1.07.1995): 506–12. http://dx.doi.org/10.1115/1.2831282.

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Powder-lubricated, quasi-hydrodynamic journal bearings assist in controlling wear and hold promise for integration in outer space systems/mechanisms and in other hostile-environment applications where the use of conventional lubricants is impractical. Described herein are the thermal phenomena and an assessment of the thermal stability, heat generation and dissipation characteristics of slider-type, powder-lubricated bearings. Powder lubricant films provide lift and separate bearing surfaces and cause side leakage. The reduction in friction coefficient and, consequently, in the heat generated in the bearings, drastically reduces wear of the tribomaterials. Further, bearing side leakage carries away most of the heat generated by shear, reducing the heat to the critical bearing surfaces. Also presented are the thermohydrodynamic effects of powder lubrication (MoS2) on bearing performance criteria, e.g., temperature and friction coefficient as a function of speed and load, including the effect of powder flow rate on bearing performance and wear.

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30

Alshaer, B. J., H. Nagarajan, H. K. Beheshti, H. M. Lankarani i S. Shivaswamy. "Dynamics of a Multibody Mechanical System With Lubricated Long Journal Bearings". Journal of Mechanical Design 127, nr 3 (17.06.2004): 493–98. http://dx.doi.org/10.1115/1.1864112.

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Clearances exist in different kinds of joints in multibody mechanical systems, which could drastically affect the dynamic behavior of the system. If the joint is dry with no lubricant, impact occurs, resulting in wear and tear of the joint. In practical engineering design of machines, joints are usually designed to operate with some lubricant. Lubricated journal bearings are designed so that even when the maximum load is applied, the joint surfaces do not come into contact with each other. In this paper, a general methodology for modeling lubricated long journal bearings in multibody mechanical systems is presented. This modeling utilizes a method of solving for the forces produced by the lubricant in a dynamically loaded long journal bearing. A perfect revolute joint in a multibody mechanical system imposes kinematic constraints, while a lubricated journal bearing joint imposes force constraints. As an application, the dynamic response of a slider-crank mechanism including a lubricated journal bearing joint between the connecting rod and the slider is considered and analyzed. The dynamic response is obtained by numerically solving the constraint equations and the forces produced by the lubricant simultaneously with the differential equations of motion and a set of initial conditions numerically. The results are compared with the previous studies performed on the same mechanism as well a dry clearance joint. It is shown that in a multibody mechanical system, the journal bearing lubricant introduces damping and stiffness to the system. The earlier studies predict that the order of magnitude of the reaction moment is twice that of a perfect revolute joint. The proposed model predicts that the reaction moment is within the same order of magnitude of the perfect joint simulation case.

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Rashidi Meybodi, R., M. Zare Mehrjardi i A. D. Rahmatabadi. "Tilt angle effects on the performance of micropolar lubricated noncircular journal bearings". Industrial Lubrication and Tribology 69, nr 4 (10.07.2017): 536–49. http://dx.doi.org/10.1108/ilt-03-2016-0041.

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Purpose The purpose of this paper is to study tilt angle effects as design parameters of noncircular bearings, on the linear dynamic analyses of micropolar lubricated circular, two, three and four lobe journal bearings. Design/methodology/approach Reynolds equation in dynamic state is modified considering the micropolarity characteristics of lubricant, and it is solved using generalized differential quadrature method. The perturbed components of the dynamic pressure are extracted based on the linear dynamic model. To explain the transient state of the governing equation, through the linear dynamic approach, the whirling motion of rotor around the steady state position is assumed to be harmonic. Findings It is observed from the results that tilt angle has significant effects on the steady state and stability performance of lobed journal bearings. It may be selected suitably to improve the performance of rotor-bearing system, while all other lubricant properties and noncircular bearing design parameters are kept fixed. Results show that among the three types of bearings considered, the dynamic performance of two lobe bearings are more affected by the variation of tilt angle. Originality/value The present study is mainly concerned with the effects of tilt angle as a design parameter on the stability performance of a hydrodynamic noncircular journal bearing lubricated with micropolar fluid.

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Chen, Pingwei, Tong Wang, Wensheng Ma, Fangzhong Li, Tianzhou Wang i Tao Chen. "Characteristic Analysis of Water Lubricated Plain Journal Bearing under Transient Load". Journal of Physics: Conference Series 2160, nr 1 (1.01.2022): 012073. http://dx.doi.org/10.1088/1742-6596/2160/1/012073.

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Abstract Transient load has a huge impact on the life and stability of water-lubricated bearings. In this paper work, CFD software is used to analyse the dynamic characteristic of water lubricated bearings under different transient loads of 500N, 1000N, 2000N and 3000N. The water film pressure contour distribution at different transient time was given. The time-varying relationships between the different transient loads with bearing forces, the journal displacement, the maximum value of water film pressure as well as the minimum value of water film thickness are obtained. The results show that with the increase of transient load, the effective bearing area of dynamic water pressure film decreases, and the maximum pressure increases. The bearing forces, the journal displacement, the maximum value of water film pressure as well as the minimum value of water film thickness will increase fast.

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Buckholz, R. H., i J. F. Lin. "The Effect of Journal Bearing Misalignment on Load and Cavitation for Non-Newtonian Lubricants". Journal of Tribology 108, nr 4 (1.10.1986): 645–54. http://dx.doi.org/10.1115/1.3261295.

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An analysis for hydrodynamic, non-Newtonian lubrication of misaligned journal bearings is given. The hydrodynamic load-carrying capacity for partial arc journal bearings lubricated by power-law, non-Newtonian fluids is calculated for small valves of the bearing aspect ratios. These results are compared with: numerical solutions to the non-Newtonian modified Reynolds equation, with Ocvirk’s experimental results for misaligned bearings, and with other numerical simulations. The cavitation (i.e., film rupture) boundary location is calculated using the Reynolds’ free-surface, boundary condition.

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Olszewski, Artur, Michał Wodtke i Piotr Hryniewicz. "Experimental Investigation of Prototype Water-Lubricated Compliant Foil Bearings". Key Engineering Materials 490 (wrzesień 2011): 97–105. http://dx.doi.org/10.4028/www.scientific.net/kem.490.97.

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First gas-lubricated compliant foil bearings (CFBs) were built in the 1950s. Due to their significant advantages, such as oil-free operation, good tolerance to bearing misalignment and very low maintenance, they have been penetrating the bearing applications for high speed compressors, air-cycle machines and gas turbines. The work presented here investigates a novel idea of water-lubricated compliant foil bearings, which could be used in applications where environmentally friendly lubrication is desired, for example in hydroelectric turbines or water pumps. Experimental results collected for three prototype water-lubricated foil journal bearings are presented. The tests were conducted under steady radial load and with the sliding speed varied incrementally. A sequence of design improvements is presented, with the best bearing demonstrating friction coefficient of about 0.01 at the sliding speed of about 4 m/s and the radial load of about 300 kPa. Encountered difficulties, research methodology and the testing equipment are also described.

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Wang, Chuang, Ziwen Xing, Xi Pan i Zhilong He. "Simulation of the characteristics of the water-lubricated journal bearing in twin-screw air compressor". Industrial Lubrication and Tribology 70, nr 8 (12.11.2018): 1476–86. http://dx.doi.org/10.1108/ilt-05-2017-0134.

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Purpose The well-operating condition of journal bearing is the assurance to keep superior performance of water-lubricated twin-screw compressor. To design the journal bearing more reasonably for this type of compressor, this paper aims to study the effects of rotating speed and design parameters on bearing characteristics, considering surface roughness and bending deformation of the shaft at the same time. Design/methodology/approach The average Reynolds equation considering the effect of surface roughness is adopted and solved by finite difference method and successive over-relaxation method to calculate pressure distribution with real bearing shapes and boundary conditions. The bending deformation of the shaft is calculated using simply supported beam model of variable cross-section. Findings The dynamic lubrication characteristics of four water-lubricated journal bearings in twin-screw air compressor are calculated and analyzed. In addition, the static characteristics of journal bearing including friction coefficient, film thickness ratio distribution and water film pressure distribution are calculated numerically with different rotating speed and design parameters. Moreover, some design principles of water-lubricated bearing for twin-screw compressor are put forward. Originality/value The lubrication characteristics of the water-lubricated journal bearing in twin-screw air compressor are calculated considering surface roughness and bending deformation of the shaft at the same time. The paper’s results may provide design guidelines for journal bearing in this kind of twin-screw compressor.

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Lu, Xiaobin, i M. M. Khonsari. "An Experimental Investigation of Grease-Lubricated Journal Bearings". Journal of Tribology 129, nr 1 (10.10.2006): 84–90. http://dx.doi.org/10.1115/1.2401216.

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A series of experimental results is presented to explore the frictional characteristics of a grease-lubricated journal bearing. Load, grease type, and bushing material are varied to examine their effects on the friction coefficient. The results attest to the existence of distinctive regimes in grease lubrication akin to the oil-lubricated Stribeck curve. A mixed elastohydrodynamic lubrication model for line contacts is employed to estimate the coefficient of friction in mixed lubrication regime. The simulation results capture the basic characteristics of mixed lubrication.

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Peng, Z.-C., i M. M. Khonsari. "A Thermohydrodynamic Analysis of Foil Journal Bearings". Journal of Tribology 128, nr 3 (16.02.2006): 534–41. http://dx.doi.org/10.1115/1.2197526.

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A thermohydrodynamic model is developed for predicting the three-dimensional (3D) temperature field in an air-lubricated, compliant foil journal bearing. The model accounts for the compressibility and the viscosity-temperature characteristic of air and the compliance of the bearing surface. The results of numerical solutions are compared to published experimental measurements and reasonable agreement has been attained. Parametric studies covering a fairly wide range of operating speeds and load conditions were carried out to illustrate the usefulness of the model in terms of predicting the thermal performance of foil journal bearings.

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McFadden, P. D., i S. R. Turnbull. "A comparison of methods of modelling the bearing surfaces in an internal combustion engine". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, nr 4 (19.09.2011): 913–20. http://dx.doi.org/10.1177/0954406211417228.

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An existing model for the dynamic analysis of the piston motion in an internal combustion engine has been modified to incorporate a simpler representation of the piston–cylinder interaction, and to represent the main and big-end bearings as lubricated rather than dry journal bearings. The results demonstrate that the differences in calculated bearing forces and output torques are negligible, indicating that the simple dry journal bearing model is sufficient, but show that the modelling of the interaction between piston and cylinder is considerably improved.

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39

Awati, Vishwanath B., i Ashwini Kengangutti. "Surface roughness effect on thermohydrodynamic analysis of journal bearings lubricated with couple stress fluids". Nonlinear Engineering 8, nr 1 (28.01.2019): 397–406. http://dx.doi.org/10.1515/nleng-2018-0017.

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Abstract The paper presents, surface roughness effect for thermo-hydrodynamic analysis of journal bearings extended to couple stress lubricants with high polymer additives. A modified energy equation is simultaneously solved with heat transfer equation as well as modified Reynolds equation by using Multigrid method. The effects of couple stress and surface roughness on the performances of a finite journal bearing are presented in detail. Further, it is shown that lubricants with couple stress and surface roughness, not only increases the load capacity and decreases the friction coefficient, but also generates a lower bearing temperature field. Thus, the lubricant with couple stress improves the performance of journal bearings. The characteristics of bearing are compared with numerical results.

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Li, Hulin, Yanzhen Wang, Ning Zhong, Yonghong Chen i Zhongwei Yin. "Study on the performance of journal bearings in different lubricants by CFD and FSI method with thermal effect and cavitation". MATEC Web of Conferences 249 (2018): 03006. http://dx.doi.org/10.1051/matecconf/201824903006.

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This paper used a new transient computational fluid dynamics and fluid–structure interaction method to investigate the journal bearing performance with the effect of thermal and cavitation, to reveal the performance of journal bearing in different lubricants and to provide substitution references for bearings in different lubricants. Considering thermal effect, elastic deformation and cavitation, a detailed discussion was conducted to show the performance of plain journal bearings lubricated by water, seawater, and lubricating oil by computational fluid dynamics (CFD) and fluid structure interaction (FSI) method. And the results in this work are compared with the published results. The variation of dimensionless load carrying capacity, maximum film pressure and temperature with eccentricity ratio are presented, which can provide reference for the design of bearings. Furthermore, a diagram is presented for journal bearings with different diameter, length-diameter ratio and lubricants, which can be used as a reference for the equivalent substitutions of bearings. The present research provides references as to the design of bearings and the substitutions of bearings by different lubricants.

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Cabrera, D. L., N. H. Woolley, D. R. Allanson i Y. D. Tridimas. "Film pressure distribution in water-lubricated rubber journal bearings". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 219, nr 2 (1.02.2005): 125–32. http://dx.doi.org/10.1243/135065005x9754.

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Measurements of fluid film pressures were made on water-lubricated rubber journal bearings. The measurements indicated that the film pressure profiles are very different from those of conventional rigid bearings. The relatively low film pressures caused significant rubber deflections but were too low to produce lubricant viscosity changes. Integration of the pressure in the bearings showed that they operate in the regime of mixed lubrication. The behaviour of the bearings was theoretically investigated using computational fluid dynamics. There was reasonable agreement between computational fluid dynamics and experimental results.

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Chauhan, Nathi Ram, Arhantika Khera, Shubhi Agarwal, Mehak Bagri i Aditi Aggarwal. "Effect of Nanoparticle on the Performance of Water Lubricated Journal Bearing". IOP Conference Series: Materials Science and Engineering 1228, nr 1 (1.03.2022): 012032. http://dx.doi.org/10.1088/1757-899x/1228/1/012032.

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Abstract Journal bearings have widespread use in machinery with rotating shafts. Hydrodynamic journal bearings have lubricating fluid present between shaft and bearing to reduce friction and allow smooth operation. The lubricating fluid develops pressure when bearing is in operation and this pressure is used to carry load on the shaft. The commonly used lubricants in the industry are petroleum based synthetic oils. To do away with the disposal issues and toxicity regarding synthetic oils, water is used as the lubricating fluid for this study. The effect of adding nanoparticles to water is studied and a program in MATLAB is developed to determine the characteristics of bearing, namely load carrying capacity, coefficients of stiffness and coefficients of damping for shaft speeds 500 rpm, 1000 rpm and 1500 rpm. It is observed that addition of nanoparticles results in increased magnitude of load carrying capacity and the bearing exhibits high value of damping and stiffness coefficients indicating stability of shaft for every speed.

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Liu, Xichun, i Wei Chen. "Structural Design and Optimization of Herringbone Grooved Journal Bearings Considering Turbulent". Applied Sciences 12, nr 1 (4.01.2022): 485. http://dx.doi.org/10.3390/app12010485.

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In order to improve the performance of the traditional constant-width herringbone grooved journal bearing in a computed tomography tube under a high-temperature environment, the present study designed a convergent herringbone grooved journal bearing (HGJB) structure lubricated by liquid metal. The bearing oil film thickness and the Reynolds equation considering the influence of turbulence are established and solved by using the finite difference method in the oblique coordinate system. The performance of the two bearings was compared, and the static and dynamic performance change trends of the two bearing structures under different eccentricities were systematically studied. The results show that the convergent herringbone grooved journal bearings are superior to the constant-width herringbone grooved journal bearings in terms of bearing capacity and stiffness coefficient. At the same time, the influence of structural parameters, such as the number of grooves, helix angle, groove to ridge ratio, groove depth on the performance of the constant-width herringbone grooved journal bearings, and the convergent herringbone grooved journal bearings was studied. Finally, we conclude that the performance of the convergent herringbone grooved journal bearings is optimal when the number of grooves is 15–20, the helix angle is 30°–45°, the ratio of the groove to ridge is 1, and the groove depth is 0.02 mm –0.024 mm. This research has provided the thinking and reference basis for the design of liquid metal bearings for high-performance CT equipment.

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Wang, Li Jun, Xiao Kang Yan, Fei Hu Li i Zi Xin Dong. "Numerical Simulation of Magnetic Fluid Lubrication". Advanced Materials Research 154-155 (październik 2010): 1498–501. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.1498.

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This paper was concerned with theoretical analysis and the static characteristics of the journal bearing lubricated with magnetic fluid. A general Reynolds equation based on magnetic fluid model is obtained, which can be easily extended to other non-Newtonian fluids and this equation can provide theoretical basis for hydrodynamic analysis of magnetic fluid journal bearings. For the case of static loaded magnetic journal bearings, the influence of magnetic fluid effects on the lubrication performance is studied under various eccentricity ratios, magnetic intensity and concentration. The numerical results show that: with the increasing of concentration, the bearing capacity is obviously increased; the increase magnitude is larger when the eccentricity ratio is large. Under the effect of magnetic field, the bearing capacity increasing with the increasing of magnetic field intensity. When the eccentricity is small, the side leakage is highly decreased. It can be completely eliminate by appropriately designing the bearing geometry and the magnetic field which can’t be existed in normal journal bearings.

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Bhattacharjee, Biplab, Prasun Chakraborti i Kishan Choudhuri. "Theoretical investigation of porous hydrostatic journal bearing under micropolar fluid lubrication". Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanomaterials, Nanoengineering and Nanosystems 234, nr 1-2 (marzec 2020): 11–18. http://dx.doi.org/10.1177/2397791420905236.

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The features of micropolar fluid (a non-Newtonian fluid)–lubricated short single-layered porous hydrostatic journal bearing are analyzed theoretically by an iterative method. To investigate hydrostatic journal bearing characteristics, a modified Reynolds equation in the case of micropolar fluid is derived and solved numerically. The obtained results in this work are validated by comparing the same with previously published results with Newtonian and non-Newtonian lubricants in the form of design charts. The static stiffness and load-carrying capacity of the investigated bearing are 80% and 75% higher than conventional hydrostatic bearings. The porous hydrostatic journal bearing exhibits more economical performance as it requires 40% low flow rate and low pump power, and it generates 50% less heat in contrast with other hydrostatic bearings.

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Lee, T. S., Y. G. Liu i S. H. Winoto. "Analysis of liquid‐lubricated herringbone grooved journal bearings". International Journal of Numerical Methods for Heat & Fluid Flow 14, nr 3 (kwiecień 2004): 341–65. http://dx.doi.org/10.1108/09615530410517995.

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Nikolakopoulos, P. G., i C. A. Papadopoulos. "Controllable Misaligned Journal Bearings, Lubricated with Smart Fluids". Journal of Intelligent Material Systems and Structures 8, nr 2 (luty 1997): 125–37. http://dx.doi.org/10.1177/1045389x9700800203.

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YOSHIMOTO, Shigeka, Kenichi OHKI, Hideyuki YATOH i Masaaki MIYATAKE. "Study on Water/Air Lubricated Hybrid Journal Bearings". Journal of the Japan Society for Precision Engineering 73, nr 12 (2007): 1335–39. http://dx.doi.org/10.2493/jjspe.73.1335.

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49

Arakere, Nagaraj K., i H. D. Nelson. "An Analysis of Gas-Lubricated Foil-Journal Bearings". Tribology Transactions 35, nr 1 (styczeń 1992): 1–10. http://dx.doi.org/10.1080/10402009208982082.

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Bou-Said, B., i J. P. Chaomleffel. "Hybrid Journal Bearings: Theoretical and Experimental Results". Journal of Tribology 111, nr 2 (1.04.1989): 265–69. http://dx.doi.org/10.1115/1.3261903.

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The analysis of actual lubrication problems needs to take into account particularities in the flow coming from kinematic conditions and contact geometry. For hybrid journal bearings lubricated by low dynamic viscosity fluid, turbulence and pressure drops due to inertia forces in the recess outlets are phenomena which must be taken into account to compute their working characteristics. A global method of study of lubricated contacts in isothermal laminar or not laminar flow by finite element method is presented. It can solve a great number of lubrication problems. A new type of approximation element for lubrication (Hermitian type) is used because it offers the following advantages: The nonlinearities in lubrication which come from turbulence phenomena, geometrical discontinuities (pressure drops) or boundary conditions (recess pressure) require the derivation of unknown functions. Added interpolations are not necessary to determine these values because the nodal unknowns are the values of the function and its derivatives in the two directions. As the modified Reynolds equation is in Cartesian coordinates, in the case of closed geometries such as journal bearings, joining is done just by nodal identification which guarantees continuity of the pressure and of its derivatives. The validity of this numerical model is realized with an experimental study done with a three recess hybrid journal bearing for different kinematic and geometric configurations. In a general way, experimental and theoretical results are in good agreement.

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