Lagare Cu Alunecare (Sliding Bearings)

Constantinescu, V. N.; Nica, Al.; Pascovici, M. D.; Ceptureanu, G.; Nedelcu, S.; Tipei, N.

doi:10.1115/1.3251661

Cited by 8 publications

(22 citation statements)

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“…A coordinate transformation is necessary to move from (O j , R, T) to (O b , X, Y). Equations (17) and (18) summarize the transformation of the stiffness matrix from the (X, Y) to (R, T) and from the (R, T) to (X, Y) reference frames, respectively. Identical transformations also apply to the added mass and damping matrices.…”

Section: Journal Bearingmentioning

confidence: 99%

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A CFD-Based Frequency Response Method Applied in the Determination of Dynamic Coefficients of Hydrodynamic Bearings. Part 1: Theory

Snyder

Braun

2019

Lubricants

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A general, CFD-based frequency response method for obtaining the dynamic coefficients of hydrodynamic bearings is presented. The method is grounded in experimental parameter identification methods and is verified for an extremely long, slider bearing geometry as well as short and long journal bearing geometries. The influence of temporal inertia on the dynamic response of the bearings is discussed and quantified through the inclusion of added mass coefficients within the mechanical models of the hydrodynamic bearing films. Methods to separate the dynamic stiffness into static stiffness and added mass contributions are presented and their results compared. Harmonic perturbations are applied to the bearings at varying frequencies to determine the frequency dependence of the dynamic coefficients and to facilitate the decomposition of the dynamic stiffness into its constituents. Added mass effects are shown to be significant for the extremely long slider bearing geometry and negligible for the short and long journal bearing geometries under operating conditions motivated by those typical of marine bearings.

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Section: Journal Bearingmentioning

confidence: 99%

“…The authors determined the bearing stiffness coefficients by curve-fitting the steady-state forces over a range of prescribed static journal eccentricities. The stiffnesses obtained using CFD were compared with Constantinescu's [18] with good coincidence.…”

Section: Introductionmentioning

confidence: 99%

A CFD-Based Frequency Response Method Applied in the Determination of Dynamic Coefficients of Hydrodynamic Bearings. Part 1: Theory

Snyder

Braun

2019

Lubricants

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“…The SATBESPIG (Figures 1 and 2 ) are special hydrodynamic bearings that have the specific effect of “autopumping” [ 1 – 3 , 5 , 7 ], which is why we are interested in the incompressible fluid motion in the laminar and permanent regime and, taking into consideration the influence of the inertial forces, in the length of the spiral groove (pumping direction ψ from Figures 3 , 4 , and 5 ). In the literature [ 4 , 7 , 10 , 12 – 15 ], there are only a few studies and a small amount of theoretical research concerning this subject.…”

Section: Constructive Geometric and Cinematic Elements Of The Satbmentioning

confidence: 99%

“…Incompressible fluid motion in “self-acting thrust bearings with spiral grooves” (SATBESPIG) is a complex motion in thin layers [ 1 – 5 ] bounded by two solid surfaces in relative rotation one to another. The incompressible fluid motion in thin layers has as mathematical consequence the simplification and particularization of the general equations of motion.…”

Section: Introductionmentioning

confidence: 99%

“…The incompressible fluid motion in thin layers has as mathematical consequence the simplification and particularization of the general equations of motion. We made this simplification of the general equations of motion by neglecting the terms smaller by more than one order of magnitude [ 1 – 7 ] than the other terms. Starting from this observation, the paper approaches the theoretical study of incompressible fluid motion in SATBESPIG with inner and exterior pumping, working in the laminar regime.…”

Section: Introductionmentioning

confidence: 99%

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Laminar Motion of the Incompressible Fluids in Self-Acting Thrust Bearings with Spiral Grooves

Velescu

Popa

2014

The Scientific World Journal

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We analyze the laminar motion of incompressible fluids in self-acting thrust bearings with spiral grooves with inner or external pumping. The purpose of the study is to find some mathematical relations useful to approach the theoretical functionality of these bearings having magnetic controllable fluids as incompressible fluids, in the presence of a controllable magnetic field. This theoretical study approaches the permanent motion regime. To validate the theoretical results, we compare them to some experimental results presented in previous papers. The laminar motion of incompressible fluids in bearings is described by the fundamental equations of fluid dynamics. We developed and particularized these equations by taking into consideration the geometrical and functional characteristics of these hydrodynamic bearings. Through the integration of the differential equation, we determined the pressure and speed distributions in bearings with length in the “pumping” direction. These pressure and speed distributions offer important information, both quantitative (concerning the bearing performances) and qualitative (evidence of the viscous-inertial effects, the fluid compressibility, etc.), for the laminar and permanent motion regime.

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