Simulation of large thrust-bearing performance at transient states, warm and cold start-up

Pajączkowski, Piotr; Schubert, Andreas; Wasilczuk, Michał; Wodtke, Michał

doi:10.1177/1350650113500483

Cited by 25 publications

(21 citation statements)

References 8 publications

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“…It was assumed similarly as in Refs. [10,16] that recess has conical shape (truncated cone, vertex cone angle 175°) with nominal base diameter equal to 170 mm, and nominal recess depth equal to 2 mm. It was planned to study both influence of the recess depth and diameter on predicted bearing parameters.…”

Section: Methodsmentioning

confidence: 99%

“…In fact, there are papers dealing with phenomena corresponding to pocket influence, but extremely rare it is included in thermoelastohydrodynamic (TEHD) models of large bearings. The only works known to the authors, which take into account this effect are papers of Pajączkowski et al [10,16], and Heinrichson [17]. Both authors include hydrostatic bearing depression of pad sliding surface in theoretical investigations of large thrust bearing properties under hydrodynamic mode of operation.…”

Section: Introductionmentioning

confidence: 99%

“…In Refs. [10,16], Kopswerk II (Austria) power plant hydrogenerator thrust bearing (outer diameter 2.3 m) was analyzed under transient states. Relatively good agreement of calculated and measured pad temperatures was obtained, but this was only parameter measured and compared.…”

Section: Introductionmentioning

confidence: 99%

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Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing

2015

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Hydrostatic assistance is a commonly used method to improve limited load carrying ability of tiltingpad thrust bearings during transient states of operation of vertical shaft hydro-generators. Despite of special hydraulic equipment (as pumps, valves, etc.), it also requires manufacturing of special recesses/pockets at pad sliding surfaces, into which oil is injected under high pressure. It allows to lift the rotor before start-up of the machine and form a hydrostatic film between pads and collar. There is a quite wide variety of geometry of recesses (shape, depth, and size) met in practical large bearing applications. The presence of a hydrostatic pocket (usually located in the sliding surface above the pivot area, where thin film, high oil pressure and temperature are observed) affects bearing performance under hydrodynamic operation.In theoretical researches, there is an almost common practice not to include hydrostatic recess in thermohydrodynamic (THD) or thermoelastohydrodynamic (TEHD) analysis. This is probably due to the problems with obtaining solution for oil film geometry with pocket, the order of magnitude of the pocket depths being larger than gap thickness. In this paper, an attempt was taken to study the effect of lifting pocket on THD performance of a large tilting-pad thrust bearing of Itaipu power plant. Bearing performance was evaluated including recess shape for several cases of its depth. The results show that hydrostatic recess changes calculated bearing properties quite significantly, especially in vicinity of the pocket.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing

2015

Self Cite

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“…Study of the literature showed, that it is a common practice to not include presence of the hydrostatic recess in evaluation of hydrodynamic bearing properties. The only works known to the authors, which take into account this effect are papers of Pajączkowski [3,9] and Heinrichson [10]. Both authors include hydrostatic bearing depression of pad sliding surface in theoretical investigations of large thrust bearing properties under hydrodynamic mode of operation.…”

Section: Introductionmentioning

confidence: 99%

“…Both authors include hydrostatic bearing depression of pad sliding surface in theoretical investigations of large thrust bearing properties under hydrodynamic mode of operation. In works [3,9], Kopswerk II (Austria) power plant hydrogenerator thrust bearing (outer diameter 2.3 m) was analyzed under transient states. Relatively good agreement of calculated and measured temperatures in the pad was obtained, but this was only parameter measured and compared.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Presence of the Lifting Pocket on the THD Performance of a Large Tilting-Pad Thrust Bearing

Fillon¹,

Wodtke²,

Wasilczuk³

2014

ABM Proceedings

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Hydrostatic assistance is a commonly used method to improve limited load carrying ability of tilting-pad thrust bearings during transient states of operation of the vertical shaft hydro-generators. Despite of special hydraulic equipment (as pumps, valves etc.), it also requires manufacturing of special recesses/pockets at the pad sliding surfaces, into which oil is injected under high pressure. It allows to lift the rotor before start-up of the machine and form a hydrostatic film between the pads and the collar. There is a quite wide variety of geometry of recesses (shape, depth, size) met in practical large bearing applications. The presence of a hydrostatic pocket (usually located in the sliding surface above the pivot area, where thin film, high oil pressure and temperature are observed) affects bearing performance under hydrodynamic operation. In theoretical researches, there is an almost common practice not to include hydrostatic recess in THD or TEHD analysis. This is probably due to the problems with obtaining solution for oil film geometry with pocket, with pocket depths order of magnitude larger than gap thickness. In this paper, an attempt was taken to study the effect of the lifting pocket on THD performance of a large tilting-pad thrust bearing of Itaipu power plant. Bearing performance was evaluated including recess shape for several cases of its depth. The results show, that hydrostatic recess changes calculated bearing properties quite significantly, especially in the vicinity of the pocket.

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Effect of cutting and feed speed on lubrication performance of large hydrostatic turntable with constant linear velocity

Yanqin,

Rong,

Jianting

et al. 2024

Lubrication Science

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The oil film lubrication performance of a large hydrostatic turntable operating at the model of constant surface cutting speed is studied. Firstly, the rotary speed equation which is bound by the constant surface cutting speed is established. According to the fluid lubrication theory, the gap flow equation, the oil film temperature rise equation and the double‐rectangular‐cavity oil pad bearing capacity equation are derived. Further, a prediction model of oil film lubrication performance in the operating mode is established. The change rules of temperature, pressure and other performance indexes of the film with time are obtained by numerical simulation. And, the above laws are verified by design experiments. It is found that the cutting speed, feed rate leaves a significant impact on the law of variations of oil film performance with time. According to the conclusions, it will be beneficial to improve the bearing capacity of the hydrostatic turntable and further improve the machining accuracy by using cutting parameters reasonably to control the speed within a certain range.

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Simulation of large thrust-bearing performance at transient states, warm and cold start-up

Cited by 25 publications

References 8 publications

Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing

Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing

Effect of the Presence of the Lifting Pocket on the THD Performance of a Large Tilting-Pad Thrust Bearing

Effect of cutting and feed speed on lubrication performance of large hydrostatic turntable with constant linear velocity

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