Analysis of the Performance of Chamfered Finite-Length Journal Bearings under Dynamic Loads

Jamali, Hazim U.; Aljibori, Hakim S. Sultan; Abdullah, Oday I.; Al-Tamimi, Adnan Naji Jameel; Albdeiri, Mahmood Shaker; Ruggiero, Alessandro; AL-Dujaili, Zahraa A.

doi:10.3390/math11030587

Cited by 8 publications

(3 citation statements)

References 35 publications

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“…With the development of computer and testing technology, the problems of tilting pad bearings in practical applications are found, dealt with and a new model to solve the problem is established. The mathematical model of fluid lubrication of tilting pad bearings is developed from a simple two-dimensional thermo hydrodynamic analysis model to a complex three-dimensional thermo hydrodynamic analysis model, and further to a complex three-dimensional thermoelastic hydrodynamic analysis model, whose computational accuracy and speed have been continuously improved [6] [7] .The effects of turbulence effect [19] [20] , rotor tilting and misalignment [17] [18] , and cavitation effect on the bearing performance such as power consumption, lubrication characteristics, temperature rise of bearing shell, and dynamic characteristics at high speeds are also considered in the theoretical analysis.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

Yang,

quan,

Chen

et al. 2024

Preprint

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Abstract：For large generator sets, during low-speed operation such as start-stop or low-speed driving, there may be instances where hydrodynamic lubrication can’t be established, leading to boundary lubrication between bearing and the shaft. This situation can result in bearing damage and cause safety incidents. Therefore, it is necessary to study the lubrication characteristics of bearings under low-speed operation. In this paper, the lubrication properties of the unevenly distributed six-pad tilting pad bearings in an in-service unit are analyzed through theoretical calculations. The analysis focuses on parameters such as film thickness and temperature of the bearing pads under low-speed operating conditions. A full-size test bench is set up to examine the lubrication properties of bearings made of two materials - Babbitt alloy and fluoroplastic, and the pads temperatures, film thicknesses, and vibration characteristics of the bearings are tested under actual operating conditions. The test results show that: the 6-pad small wrap angle bearings designed do not have tile burning phenomenon under low-speed working condition (40r/min), the bearing made of fluoroplastic material has lower temperatures compared to those made of Babbitt alloy, with higher pivot film thickness than that of the Babbitt alloy; The bearing pivot film thickness value using VG68 oil is larger than that of VG46, and the values of the temperature of the pad measurement point are larger than that of VG46.This research paper validates the feasibility of the bearing design scheme for this unit and provides data support for the design and safe operation of similar units.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

Yang,

quan,

Chen

et al. 2024

Preprint

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“…Furthermore, the effect of bearing modification considering dynamic load was investigated by Jamali at el. [34] but with a limited linear chamfer model and without a detailed investigation into the effect of chamfer parameters on the friction coefficient. Friction (as well as wear) is another important aspect in designing the journal bearing, which also has been investigated extensively by researchers as a result of its direct relation to general bearing performance [35,36].…”

Section: Introductionmentioning

confidence: 99%

Effect of Chamfer Form and Parameters on the Characteristics of Finite Length Journal Bearing under Impact Load

et al. 2023

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Journal bearings in typical applications are subjected to misalignment due to several causes, such as shaft deformation under load and errors related to the installation and manufacturing processes. Misalignment has well-known severe negative consequences on the performance of the bearings. This paper deals with the bearing chamfer to reduce these consequences of misalignment, and two forms of bearing edge modification are considered in the analysis. These forms are linear and curved chamfering of the bearing edges, where the height of the chamfer in the circumferential direction and the length of the modification in the longitudinal direction are considered as geometrical design parameters. The investigation includes a numerical solution of the hydrodynamic lubrication problem of finite length journal bearing, considering 3D misalignment cases using the finite difference method. This includes the assessment of the chamfer forms and their effects on the bearing performance in terms of the main bearing design parameters. Furthermore, the stability of the chamfered bearings is also investigated under impact load. Results showed that both chamfer forms are beneficial for a certain limit of the design parameters in reducing the maximum pressure and coefficient of friction and in elevating the film thickness levels, extending the range of misalignment in which the journal bearing can operate safely. In addition, the chamfered bearings in both forms showed more stability range in terms of the critical speed and shaft center trajectories under impact load. The bearings with the curved chamfer, where the slope is continuous at the start of modification, showed more uniform film thickness levels, and their shaft center trajectories were closer to the perfectly aligned bearing in the stable operating range of the system.

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“…Furthermore, it has been reported that the use of double bladder structures can enhance the stability of water-lubricated bearings when subjected to half-sine shock load [37]. A study was conducted using a chamfer and profile to improve the lubrication characteristics of misaligned journal bearings under conditions where no shock load was applied [38] Moreover, lobe-type profiles or pockets were applied to the bearings to improve the lubrication characteristics under impact load conditions [37][38][39][40]. A study was conducted using a chamfer and profile to improve the lubrication characteristics of misaligned journal bearings under conditions where no shock load was applied [41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Lubrication Performance of Misaligned Journal Bearings with Flexible Structure under Shock Load Conditions

Hong,

Jeon

2023

Lubricants

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Bearings might be damaged due to shock loads caused by disturbances, in addition to static loads. In this study, a flexible structure was applied to enhance the lubrication characteristics of misaligned journal bearings subjected to impact loads. When an impact load is added to the bearing, a misaligned journal bearing has a high possibility of metal-to-metal contact. It might also lead to failure. Misalignment can occur at any time during bearing operation. A flexible structure is applied to the end of the bearing as a way to improve lubrication performance in a system where impact loads might be applied. The bearing’s lubrication performance was numerically assessed under unsteady-state conditions. An elastohydrodynamic lubrication analysis was conducted, taking into account elastic deformation. The lubrication characteristics of misaligned journal bearings were compared with the dimensionless minimum film thickness. The flexible structure and elastic modulus of the bearing were investigated so that it could support the load without contact according to the change in the maximum magnitude of the impact load. When subjected to oil film pressure, this flexible structure underwent elastic deformation, resulting in enlargement of the oil film. A misaligned journal bearing with a suitable flexible structure provided stable lubrication without metal-to-metal contact, even under shock load conditions. The flexible structure was incorporated into the high-load-bearing region of the journal bearing as a groove. Therefore, the application of a flexible structure in misaligned journal bearings can effectively enhance lubrication performance in misaligned conditions and under shock loads.

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Analysis of the Performance of Chamfered Finite-Length Journal Bearings under Dynamic Loads

Cited by 8 publications

References 35 publications

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

Effect of Chamfer Form and Parameters on the Characteristics of Finite Length Journal Bearing under Impact Load

Lubrication Performance of Misaligned Journal Bearings with Flexible Structure under Shock Load Conditions

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