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Jiaxu Wang - One of the best experts on this subject based on the ideXlab platform.
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A numerical method to investigate the Mixed Lubrication performances of journal-thrust coupled bearings
Industrial Lubrication and Tribology, 2019Co-Authors: Guo Xiang, Yanfeng Han, Jiaxu Wang, Renxiang Chen, Ni XiaokangAbstract:This paper aims to present a numerical model to investigate the Mixed Lubrication performances of journal-thrust coupled bearings (or coupled bearings).,The coupled hydrodynamic effect (or coupled effect) between the journal and the thrust bearing is considered by ensuring the continuity of the hydrodynamic pressure and the flow field at the common boundary. The Mixed Lubrication performances of the coupled bearing are comparatively studied for the cases of considering and not considering coupled effect.,The simulated results show that the hydrodynamic pressure distributions for both the journal and thrust bearing are modified due to the coupled effect. The decreased load capacity of the journal bearing and the increased load capacity of the thrust bearing can be observed when the coupled effect is considered. And the coupled effect can facilitate in reducing the asperity contact load for both the journal and thrust bearing. Additionally, the interaction between the Mixed Lubrication behaviors, especially for the friction coefficient, of the journal and the thrust bearing is significant in the elastohydrodynamic Lubrication regime, while it becomes weak in the Mixed Lubrication regime.,The developed model can reveal the mutual effects of the Mixed Lubrication behavior between the journal and the thrust bearing.
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Numerical Investigation on the Mixed Lubrication Performance of Water-Lubricated Coupled Journal and Thrust Bearings
Volume 10: 2019 International Power Transmission and Gearing Conference, 2019Co-Authors: Yanfeng Han, Guo Xiang, Jiaxu WangAbstract:Abstract The Mixed Lubrication performance of water-lubricated coupled journal and thrust bearing (simplified as coupled bearing) is investigated by a developed numerical model. To ensure the continuity of hydrodynamic pressure and flow at the common boundary between the journal and thrust bearing, the conformal transformation is introduced to unify the solution domain of the Reynolds equation. In the presented study, the coupled effects between the journal and thrust bearing are discussed. The effects of the thrust bearing geometric film thickness on the Mixed Lubrication performance, including the load capacity, contact load and friction coefficient, of the journal bearing are investigated. And the effects of the journal bearing eccentricity ratio on the Mixed Lubrication performance of the thrust bearing are also investigated. The simulated results indicate the mutual effects between the journal and thrust bearing cannot be ignored in the coupled bearing system. The increasing thrust bearing geometric film thickness generates a decrease in load capacity of journal bearing. There exists an optimal eccentricity ratio of journal bearing that yields the minimum friction coefficient of the thrust bearing.
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Coupling transient Mixed Lubrication and wear for journal bearing modeling
Tribology International, 2019Co-Authors: Guo Xiang, Yanfeng Han, Jiaxu Wang, Jiefu Wang, Ni XiaokangAbstract:Abstract A transient Mixed Lubrication-Wear coupling model (MLW coupling model) is developed to investigate the Mixed Lubrication and wear performances of journal bearings, and a wear experiment for journal bearing is performed to support the validity of the developed numerical model. In the coupling numerical model, the transient interaction between the behaviour of Mixed Lubrication and wear is considered by incorporating the wear depth distribution, which is determined by the developed friction fatigue wear model, into the film gap equation. The evolutions of the worn surface profile, wear rate, fluid pressure and asperity contact pressure over operating time are calculated by the developed numerical model. The simulated results demonstrate that the transient wear process affects the distribution trend of Lubrication performances significantly, and a worn surface profile may exist that provides an optimal tribology performance of journal bearings. The simulated results also demonstrate that there are two wear stages, identified by initial and steady wear stage, of journal bearings under Mixed Lubrication condition. Furthermore, the effects of the input parameters, including the radius clearance(C), surface roughness (σ), asperity curvature radius (β) and boundary friction coefficient(μc), on the predicted Mixed Lubrication and wear performance are evaluated.
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A numerical method to investigate the temperature behavior of spiral bevel gears under Mixed Lubrication condition
Applied Thermal Engineering, 2019Co-Authors: Lai Gan, Jiaxu Wang, Ke Xiao, Wei CaoAbstract:Abstract Thermal behaviors under Mixed Lubrication regime are closely to the load-carrying capacity of spiral bevel gears, especially, in heavy load and high speed. In order to analyze the bulk and flash temperature behaviors, this paper proposes a numerical method which integrates the Mixed elastohydrodynamic Lubrication model with a finite element method based on thermal analysis. Heat generation in Mixed Lubrication regime is determined as functions of the applied load, sliding velocityand friction coefficient. The friction is solved by recently developed Mixed elastohydrodynamic Lubrication model with the consideration of surface roughness and arbitrary entrainment angle. Heat transfer analysis is conducted by application of the time- and position-varying heat flux and convection coefficient boundary condition on single tooth finite element model. The results clearly show that the major high temperature zone for bulk temperature is located nearby tooth root and the temperature in boundary Lubrication is more serious compared with Mixed Lubrication. The edge contact at the tooth top leads to severe high temperature. The flash temperature behavior in entire rotation period indicates the influence of thermal characteristics on risk of scuffing.
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Analysis of Mixed Lubrication of RV reducer turning arm roller bearing
Industrial Lubrication and Tribology, 2018Co-Authors: Zhenhua Zhang, Jiaxu Wang, Guangwu Zhou, Pei XinAbstract:Purpose The purpose is aimed to solve the Lubrication failures in the turning arm bearing of RV reducer, and give some help in perfect the bearing structure design and provide theoretical basis for the reducer’s performance improvement. Design/methodology/approach The paper establishes a Mixed Lubrication analysis model to study performance parameters. According to the discretization of parameters and iteration of equations, numerical simulation and theoretical analysis are achieved in computational process. Findings Considering influences of contact load, real rough surface and realistic geometry of RV reducer turning arm roller bearing, the Mixed Lubrication analysis model is established to study the ratio of oil film thickness, pressure distribution, and maximum von Mises stress in different speed, temperature and fillets. The results of Mixed Lubrication show that reasonable round corner modification, increase of temperature and speed, decrease of surface roughness and lubricant types can improve the ...
Hui Wang - One of the best experts on this subject based on the ideXlab platform.
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Deterministic solutions and thermal analysis for Mixed Lubrication in point contacts
Tribology International, 2007Co-Authors: Wen-zhong Wang, Yuchuan Liu, Hui WangAbstract:A deterministic numerical model has been developed for simulation of Mixed Lubrication in point contacts. The nominal contact area between rough surfaces can be divided into two parts: the regions for hydrodynamic Lubrication and asperity contacts (boundary Lubrication). In the area where the film thickness approaches zero the Reynolds equation can be modified into a reduced form and the normal pressure in the region of asperity contacts can be thus determined. As a result, a deterministic numerical solution for the Mixed Lubrication can be obtained through a unite system of equations and the same numerical scheme. In thermal analysis, the solution for a moving point heat source has been integrated numerically to get surface temperature, provided that shear stresses in both regions of hydrodynamic Lubrication and asperity contacts have been predetermined. A rheology model based on the limit shear stress of lubricant is proposed while calculating the shear stress, which gives a smooth transition of friction forces between the hydrodynamic and contact regions. The computations prove the model to be a powerful tool to provide deterministic solutions for Mixed Lubrication over a wide range of film thickness, from full-film to the Lubrication with very low lambda ratio, even down to the region where the asperity contact dominates.
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Effect of surface roughness parameters on Mixed Lubrication characteristics
Tribology International, 2006Co-Authors: Wen-zhong Wang, Hui Chen, Hui WangAbstract:In this paper, a computer program was developed to generate non-Gaussian surfaces with specified standard deviation, autocorrelation function, skewness and kurtosis, based on digital FIR technique. A thermal model of Mixed Lubrication in point contacts is proposed, and used to study the roughness effect. The area ratio, load ratio, maximum pressure, maximum surface temperature and average film thickness as a function of skewness and kurtosis are studied at different value of rms. Numerical examples show that skewness and kurtosis have a great effect on the contact parameters of Mixed Lubrication.
Ni Xiaokang - One of the best experts on this subject based on the ideXlab platform.
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A numerical method to investigate the Mixed Lubrication performances of journal-thrust coupled bearings
Industrial Lubrication and Tribology, 2019Co-Authors: Guo Xiang, Yanfeng Han, Jiaxu Wang, Renxiang Chen, Ni XiaokangAbstract:This paper aims to present a numerical model to investigate the Mixed Lubrication performances of journal-thrust coupled bearings (or coupled bearings).,The coupled hydrodynamic effect (or coupled effect) between the journal and the thrust bearing is considered by ensuring the continuity of the hydrodynamic pressure and the flow field at the common boundary. The Mixed Lubrication performances of the coupled bearing are comparatively studied for the cases of considering and not considering coupled effect.,The simulated results show that the hydrodynamic pressure distributions for both the journal and thrust bearing are modified due to the coupled effect. The decreased load capacity of the journal bearing and the increased load capacity of the thrust bearing can be observed when the coupled effect is considered. And the coupled effect can facilitate in reducing the asperity contact load for both the journal and thrust bearing. Additionally, the interaction between the Mixed Lubrication behaviors, especially for the friction coefficient, of the journal and the thrust bearing is significant in the elastohydrodynamic Lubrication regime, while it becomes weak in the Mixed Lubrication regime.,The developed model can reveal the mutual effects of the Mixed Lubrication behavior between the journal and the thrust bearing.
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Coupling transient Mixed Lubrication and wear for journal bearing modeling
Tribology International, 2019Co-Authors: Guo Xiang, Yanfeng Han, Jiaxu Wang, Jiefu Wang, Ni XiaokangAbstract:Abstract A transient Mixed Lubrication-Wear coupling model (MLW coupling model) is developed to investigate the Mixed Lubrication and wear performances of journal bearings, and a wear experiment for journal bearing is performed to support the validity of the developed numerical model. In the coupling numerical model, the transient interaction between the behaviour of Mixed Lubrication and wear is considered by incorporating the wear depth distribution, which is determined by the developed friction fatigue wear model, into the film gap equation. The evolutions of the worn surface profile, wear rate, fluid pressure and asperity contact pressure over operating time are calculated by the developed numerical model. The simulated results demonstrate that the transient wear process affects the distribution trend of Lubrication performances significantly, and a worn surface profile may exist that provides an optimal tribology performance of journal bearings. The simulated results also demonstrate that there are two wear stages, identified by initial and steady wear stage, of journal bearings under Mixed Lubrication condition. Furthermore, the effects of the input parameters, including the radius clearance(C), surface roughness (σ), asperity curvature radius (β) and boundary friction coefficient(μc), on the predicted Mixed Lubrication and wear performance are evaluated.
Chunxiao Jiao - One of the best experts on this subject based on the ideXlab platform.
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Mixed-Lubrication analysis of misaligned bearing considering turbulence
Tribology International, 2018Co-Authors: Chunxiao Jiao, Zhushi RaoAbstract:Abstract Some bearings operate in Mixed-Lubrication regime due to the low rotational speed and the heavy load and misalign due to shaft's gravity. For large bearings, the maximum film thickness is much larger than minimum nominal film thickness and turbulence may locally develop. This paper proposes an approach to analyze misaligned Mixed-Lubrication bearing considering turbulence. Based on the average flow model proposed by Patir and Cheng and the Ng-Pan turbulence model, a generalized average Reynolds equation is derived. The calculation procedure is established by finite difference method. The results show that turbulence remarkably increases friction coefficient, slightly increases the minimum nominal film thickness, and decreases the transition speed from Mixed-Lubrication regime to hydrodynamic Lubrication regime.
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Mixed Lubrication analysis of thin polymer film overplayed metallic marine stern bearing considering wall slip and journal misalignment
Tribology International, 2017Co-Authors: Zhushi Rao, Chunxiao JiaoAbstract:Abstract To study the tribological properties of thin polymer film overplayed metallic stern bearings, in this paper a Mixed-Lubrication model considering two-dimensional wall slip and journal misalignment is developed. Based on the average flow model proposed by Patir and Cheng, an extended average Reynolds equation considering circumferential and axial slip is derived in terms of interfacial limiting shear stress model. The calculation procedure is established by using finite difference method and over-relaxation iterative method. The results show that both wall slip and journal misalignment reduce the minimum nominal film thickness, increase friction coefficient of bearing in Mixed-Lubrication regime, and raise journal's speed at which transition from Mixed-Lubrication to hydrodynamic Lubrication occurs.
Guo Xiang - One of the best experts on this subject based on the ideXlab platform.
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A numerical method to investigate the Mixed Lubrication performances of journal-thrust coupled bearings
Industrial Lubrication and Tribology, 2019Co-Authors: Guo Xiang, Yanfeng Han, Jiaxu Wang, Renxiang Chen, Ni XiaokangAbstract:This paper aims to present a numerical model to investigate the Mixed Lubrication performances of journal-thrust coupled bearings (or coupled bearings).,The coupled hydrodynamic effect (or coupled effect) between the journal and the thrust bearing is considered by ensuring the continuity of the hydrodynamic pressure and the flow field at the common boundary. The Mixed Lubrication performances of the coupled bearing are comparatively studied for the cases of considering and not considering coupled effect.,The simulated results show that the hydrodynamic pressure distributions for both the journal and thrust bearing are modified due to the coupled effect. The decreased load capacity of the journal bearing and the increased load capacity of the thrust bearing can be observed when the coupled effect is considered. And the coupled effect can facilitate in reducing the asperity contact load for both the journal and thrust bearing. Additionally, the interaction between the Mixed Lubrication behaviors, especially for the friction coefficient, of the journal and the thrust bearing is significant in the elastohydrodynamic Lubrication regime, while it becomes weak in the Mixed Lubrication regime.,The developed model can reveal the mutual effects of the Mixed Lubrication behavior between the journal and the thrust bearing.
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Numerical Investigation on the Mixed Lubrication Performance of Water-Lubricated Coupled Journal and Thrust Bearings
Volume 10: 2019 International Power Transmission and Gearing Conference, 2019Co-Authors: Yanfeng Han, Guo Xiang, Jiaxu WangAbstract:Abstract The Mixed Lubrication performance of water-lubricated coupled journal and thrust bearing (simplified as coupled bearing) is investigated by a developed numerical model. To ensure the continuity of hydrodynamic pressure and flow at the common boundary between the journal and thrust bearing, the conformal transformation is introduced to unify the solution domain of the Reynolds equation. In the presented study, the coupled effects between the journal and thrust bearing are discussed. The effects of the thrust bearing geometric film thickness on the Mixed Lubrication performance, including the load capacity, contact load and friction coefficient, of the journal bearing are investigated. And the effects of the journal bearing eccentricity ratio on the Mixed Lubrication performance of the thrust bearing are also investigated. The simulated results indicate the mutual effects between the journal and thrust bearing cannot be ignored in the coupled bearing system. The increasing thrust bearing geometric film thickness generates a decrease in load capacity of journal bearing. There exists an optimal eccentricity ratio of journal bearing that yields the minimum friction coefficient of the thrust bearing.
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Coupling transient Mixed Lubrication and wear for journal bearing modeling
Tribology International, 2019Co-Authors: Guo Xiang, Yanfeng Han, Jiaxu Wang, Jiefu Wang, Ni XiaokangAbstract:Abstract A transient Mixed Lubrication-Wear coupling model (MLW coupling model) is developed to investigate the Mixed Lubrication and wear performances of journal bearings, and a wear experiment for journal bearing is performed to support the validity of the developed numerical model. In the coupling numerical model, the transient interaction between the behaviour of Mixed Lubrication and wear is considered by incorporating the wear depth distribution, which is determined by the developed friction fatigue wear model, into the film gap equation. The evolutions of the worn surface profile, wear rate, fluid pressure and asperity contact pressure over operating time are calculated by the developed numerical model. The simulated results demonstrate that the transient wear process affects the distribution trend of Lubrication performances significantly, and a worn surface profile may exist that provides an optimal tribology performance of journal bearings. The simulated results also demonstrate that there are two wear stages, identified by initial and steady wear stage, of journal bearings under Mixed Lubrication condition. Furthermore, the effects of the input parameters, including the radius clearance(C), surface roughness (σ), asperity curvature radius (β) and boundary friction coefficient(μc), on the predicted Mixed Lubrication and wear performance are evaluated.
