The Effects of Geometric Irregularities of Journals on the Performance of Porous Bearings
01 Jun 1994-Vol. 208, Iss: 2, pp 141-145
TL;DR: In the theoretical analysis of porous bearings, the journal has so far been assumed to be ideal, that is perfectly cylindrical as discussed by the authors, but in the present analysis the geometric irregularities of the journal, s
Abstract: In the theoretical analysis of porous bearings the journal has so far been assumed to be ideal, that is perfectly cylindrical. In the present analysis the geometric irregularities of the journal, s...
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TL;DR: In this paper, the effect of geometric imperfections of journal on the performance of micropolar lubricated 4-pocket hybrid journal bearing was theoretically described and numerically simulated results were presented for different forms of geometric irregularities of journal such as barrel shape, bellmouth shape, circumferential undulations along with the ideal shape for both the Newtonian and micropolic lubricant.
29 citations
TL;DR: In this article, the effect of misalignment of journal in conjunction with geometric imperfections of journal on the performance of four pocket hybrid journal bearing system has been investigated and the numerically simulated results indicate that the performance gets significantly deteriorated due to the geometric imperfection and mis alignment of journal.
25 citations
01 Jan 2015
TL;DR: In this article, the influence of journal's geometric imperfections on the performance of a capillary compensated two-lobe hybrid journal bearing system was investigated, and numerically simulated results indicated that non-circularity of bearing and barrel shape irregularity significantly increase the values of S¯zz,C¯zz and ω¯th by a factor 36.47, 51.34 and 18.52%, respectively, with respect to the base bearing (circular ideal journal bearing) operating with non-Newtonian lubricant.
Abstract: The present paper investigates the influence of journal’s geometric imperfections on the performance of capillary compensated two-lobe hybrid journal bearing system. Different geometric imperfections of journal, viz. barrel, bellmouth and circumferential waviness have been included in the study. A parameter called offset factor has been included in the analysis which distinguishes between two lobe and circular journal bearing. Further, the Reynolds equation has been modified by using power law model in order to deal with non-Newtonian effect of the lubricant. The numerically simulated results indicate that non-circularity of bearing and barrel shape irregularity significantly increase the values of S¯zz,C¯zz and ω¯th by a factor 36.47, 51.34 and 18.52%, respectively, with respect to the base bearing (circular ideal journal bearing) operating with non-Newtonian lubricant.
15 citations
Cites background from "The Effects of Geometric Irregulari..."
...There are five undulations (geometric irregularity in circumference direction of journaln1) which have been taken in the analysis.(20) In the case of ideal journal (journal free from geometric irregularities)...
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TL;DR: In this article, the influence of geometric irregularities on the performance of membrane compensated four pocket journal bearing under misaligned conditions is examined and the unknown fluid film pressure field in governing Reynolds equation is obtained by FE analysis using Gallerkin's technique.
14 citations
TL;DR: In this article, the authors present an analysis of the performance characteristics of a journal bearing with three-dimensional asperities operating in a turbulent regime, based on the linearized lubrication theory.
14 citations
References
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TL;DR: In this article, finite element methods are used to solve hydrodynamic lubrication problems involving compressible lubricants and porous bearing solids, and the particular calculation scheme permits solution at high compressibility numbers (Λ > 100) to be obtained without any numerical difficulty.
Abstract: Finite element methods are used to solve hydrodynamic lubrication problems involving compressible lubricants and porous bearing solids. The particular calculation scheme permits solution at high compressibility numbers (Λ > 100) to be obtained without any numerical difficulty. Finite element and finite difference results for the porous, gas lubricated journal bearing are presented and compared.
27 citations
26 citations
TL;DR: In this article, the effects of velocity slip on the static performance as well as on the dynamic performance of the bearings are determined, and the slip coefficient is treated as an independent parameter and the porosity and the ratio of clearance to journal radius are the other factors which determine the effect of slip.
21 citations
17 citations
TL;DR: In this article, the porosity and the development of internal stresses in the porous matrix by plastic deformation is investigated. And the effect of porosity on the oil-film pressures developed in the hydrodynamic lubrication of porous metal parts is illustrated, together with the result of variable porosity in the direction of pressing.
Abstract: The elastic behaviour of porous metals under compressive stress is shown to depend upon the porosity and the development of internal stresses in the porous matrix by plastic deformation. The elastic modulus obtained from the measurement of the recoverable strain following plastic deformation is given for porous bronze and iron. The stress/strain behaviour of porous metals is similar to that of cast iron in tension, in which the graphite acts as porosity. Poisson’s ratio for porous iron was found to be between 0.2 and 0.25. A practical example of the application of the data to the force-fitting of porous metal parts into rigid housings is given. The effect of porosity on the oil-film pressures developed in the hydrodynamic lubrication of porous metal parts is illustrated, together with the result of variable porosity and permeability in the direction of pressing.
14 citations