Numerical investigation of the effect of manufacturing errors in pads on the behaviour of tilting-pad journal bearings

Dang, Phuoc Vinh; Chatterton, Steven; Pennacchi, Paolo; Vania, A.

doi:10.1177/1350650117721118

Cited by 31 publications

(18 citation statements)

References 25 publications

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“…The TEHD model of the TPJB is similar to that developed and described by the same authors in [36][37][38][39] and improved for the thermal aspect, as partially done in [40] for sleeve journal bearings. The model mainly includes the laws of hydrodynamic lubrication, the thermal model of the oil-films, pads and shaft and the flexibility of the pivots.…”

Section: Tehd Bearing Modelmentioning

confidence: 99%

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The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

2019

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The role of the pivot flexibility in tilting-pad journal bearings (TPJBs) has become essential, particularly for bearings working at high applied load and relatively high rotor speeds. Predictions from a simple bearing model with rigid pivots show incorrect estimation of the dynamic coefficients in comparison with the experimental results. Normally, the more flexible the pad pivot, the lower the dynamic coefficients because the stiffness of the pivot takes in series with the stiffness and damping of the oil film. This paper investigates the influence of pivot stiffness on the dynamic force coefficients of two different five-pad TPJBs as a function of the applied static load and excitation frequency: rocker-backed pivot and spherical pivot bearings. In order to highlight the effect of the pivot stiffness in the spherical pivot bearing, displacement restriction components and elastic copper made shims have been used. Firstly, a thermo-elasto-hydrodynamic model for the static and dynamic characteristics of the two bearings is described. This model takes into account the flexibility of both pad and pivot. The pivot stiffnesses calculated by means of the Hertz theory and those obtained by experiments have been introduced and compared in the model. The clearance profiles of two tested bearing and the shaft center loci obtained by measurement and prediction are also shown. The dynamic coefficients of the two bearings obtained from the numerical simulation were compared with the experimental results. By the analysis it can be concluded that the effect of the pivot flexibility on the clearance profile, the shaft locus and on the dynamic coefficients is very significant. More important, it is important to estimate the pivot stiffness of each single pad using experimental measurements.

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Section: Tehd Bearing Modelmentioning

confidence: 99%

“…In the model, a tetrahedral mesh has been used for the finite element analysis (see Figure 3b). Readers are strongly recommended to refer [37] for deeply understand the model. Note that the pad model also considers two parts of each pad, i.e., the pad base (steel) and the pad sets (Babbitt layer with a thick of 3 mm).…”

Section: Tehd Bearing Modelmentioning

confidence: 99%

The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

2019

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“…The TEHD model of the TPJB bearing is similar to that developed and described by the same authors in [22,23] and improved with respect to the thermal aspect, as partially undertaken in [24] for sleeve journal bearings. The model primarily includes the laws of hydrodynamic lubrication, the three-dimensional thermal model of the oil-films, pads and shaft and the flexibility of the pivots.…”

Section: Bearing Modelmentioning

confidence: 99%

“…where X s and Y s represent the shaft centre position O s = (X s , Y s ) in the cartesian reference system X − Y, θ k represents the tilt angle of the k-th pad, and η k represents the displacement of the k-th pad along the radial direction due to the flexibility of the pivot. The flexibility k pivot of the pivot along the η direction has been evaluated by means of the contact Hertz theory [23]:…”

Section: Bearing Geometry and Quantitiesmentioning

confidence: 99%

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Cooled Pads for Tilting-Pad Journal Bearings

et al. 2019

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Tilting-pad journal bearings (TPJBs) are widely installed in rotating machines owing to their high stability, but some drawbacks can be noted, such as higher cost with respect to cylindrical journal bearings and thermal issues. High temperatures in the pads correspond to low oil-film thicknesses and large thermal deformations in the pads. Therefore, the restriction of the maximum temperature of the bearing is a key aspect for oil-film bearings. The temperature reduction is generally obtained by adopting higher oil inlet flowrates or suitable oil nozzles. In this paper, the idea of using cooled pads with internal channels in which an external cooling fluid is circulated will be applied to a TPJB for the first time. The three-dimensional TEHD model of the TPJB, equipped with a cooled pad, will be introduced, and the results of the numerical simulations will be discussed. Several analyses have been performed in order to investigate the influence of cooling conditions, such as the type, flowrate, inlet temperature and number of cooled pads. Two types of pad geometry with different cross-sections of the cooling circuit, namely, circular and six-square multi-channel sections, have been compared to the reference bearing with solid pads. Simple experimental tests were performed by means of a test rig equipped with a cooled pad bearing obtained with the additive manufacturing process, thus showing the effectiveness of the solution and the agreement with the predictions.

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