Effects of Tilting Pad Journal Bearing Design Parameters on the Pad-Pivot Friction and Nonlinear Rotordynamic Bifurcations

Kim, Sitae; Byun, Sung Su; Suh, Junho

doi:10.3390/app10165406

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Bearing performance is improved by optimizing bearing structural parameters such as tile wrap angle [10] , aspect ratio [11] , bearing clearance [12] , pivot position [13] and pivot flexibility [14][15] [16] . Over the years, a large number of theoretical and experimental studies have provided an important assessment basis for the design and reliability application of tilting pad bearings, forming a common knowledge support [8] [9] .…”

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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“…Shi et al 30 explored the pivot stiffness effect on the dynamic response of horizontal and vertical rotors supported on TPJBs. Kim et al 31,32 analyzed the nonlinear rotordynamic response of TPJBs considering pad-pivot friction forces. Rendl et al 33 presented a nonlinear dynamic analysis of a four-pad TPJB in load-between-pads (LBP) configuration, supported on flexible pivots.…”

Section: Introductionmentioning

confidence: 99%

Effect of direct injection and pivot stiffness on the static performance parameters of tilting pad journal bearings

Peixoto

Tuckmantel

Daniel

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part J:

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This work presents a thermo-hydrodynamic model of a tilting pad journal bearing (TPJB) supported on flexible pivots and considering direct injection on the bearing gap. It initially investigates separately each effect on the static characteristics of a TPJB and after, the concomitant influence of both mechanisms on the bearing performance. The study reveals both mechanisms of direct injection and pivot deflection affect the lubricant pressure and temperature distribution. Direct injection is a local effect, mainly influencing the pressure around the injection orifice and the temperature downward it. Pivot flexibility reduces the lubricant pressure and the temperature rise, as the film thickness increases with pivot deflection. For soft pivots, direct injection may reduce even further the lubricant temperature. As the pivot stiffness reduces, the journal displacement increases, but the drag torque is reduced, indicating that bearing mechanical efficiency may be increased if the tilting pads are supported on flexible pivots, whether the journal displacement is within acceptable bounds. Each considered mechanism in a TPJB may affect its performance and should be modeled accordingly.

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“…He et al [15] showed that varying bearing loads, the pivot friction could result in non-synchronous pad tilting and journal vibrations. Kim et al [16,17] focused on the pad-pivot friction-induced nonlinear rotor dynamic phenomena and bifurcations. The Stribeck curve model was applied for friction.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Pivot Rolling Motion Effect on the Behavior of Rocker Back Tilting Pad Journal Bearings

Betti

Forte

Panara³

et al. 2023

Applied Sciences

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The rolling motion of the pads with rocker back (RB) and ball and socket pivots is normally neglected in common software programs for the study of the rotor dynamic behavior of tilting pad journal bearings (TPJB). In other words, the theoretical contact point of the pivot is considered fixed. The aim of this work is to provide a novel way to implement in commercial software the effect of the variation of the circumferential coordinate of the theoretical contact point due to the pad rolling motion in RB TPJB. This is done by introducing an equivalent pivot rotational stiffness evaluated with an analytically derived formula, validated through finite element analysis. Such a stiffness is a function of the pad load and the radii of the contact pair, increasing with the load, the radii, and the degree of conformity of the contact. The static and dynamic characteristics of a five pad RB TPJB are then evaluated with a commercial software with and without the rotational stiffness contribution for two different pivot geometries. Non-negligible differences were found, particularly regarding the cross-coupled dynamic coefficients that show the higher sensitivity to the rotational stiffness. The inclusion of a pivot rotational stiffness among the data of commercial software for simulation of RB TPJB could contribute to fill the gap between numerical and experimental results.

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Effects of Tilting Pad Journal Bearing Design Parameters on the Pad-Pivot Friction and Nonlinear Rotordynamic Bifurcations

Cited by 6 publications

References 13 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 direct injection and pivot stiffness on the static performance parameters of tilting pad journal bearings

Investigation on Pivot Rolling Motion Effect on the Behavior of Rocker Back Tilting Pad Journal Bearings

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