Generalized One-Dimensional Reynolds' Equation for Micropolar Fluid Film Lubrication

Author(s):  
V.C.C. Raju ◽  
R.Y. Vasudeva ◽  
G. Yegnanarayana
Author(s):  
Silun Zhang ◽  
Mohamed-Amine Hassini ◽  
Mihai Arghir

The present work is focused on the numerical solution of the complete energy equation used in fluid film lubrication. The work was motivated by the fact the complete energy equation has no analytic solution that could be used for validations. Its accuracy and computation time are related to the employed numerical method and to the grid resolution. The natural discretization method (NDM) applied on different grids is systematically compared with the spectral method (the Lobatto Point Colocation Method or LPCM) with different polynomial degrees. A one dimensional inclined slider is used for the numerical tests and the energy equation is artificially decoupled from Reynolds. This approach enables to focus all the attention on the numerical solution of the energy equation. The results show that the LPCM is one or two orders of magnitudes more efficient than the NDM in terms of computation time. The energy equation is then coupled with Reynolds equation in a thermo-hydrodynamic analysis of the same 1D slider; the numerical results confirm again the efficiency of the LPCM. A thermo-hydrodynamic analysis of a two-lobe journal bearing is then presented as a practical application.


Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 95
Author(s):  
Silun Zhang ◽  
Mohamed-Amine Hassini ◽  
Mihai Arghir

The present work is focused on the numerical solution of the complete energy equation used in fluid film lubrication. The work was motivated by the fact that the complete energy equation has no analytical solution that can be used for validations. Its accuracy and computation time are related to the employed numerical method and to the grid resolution. The natural discretization method (NDM) applied on different grids is systematically compared with the spectral method (the Lobatto Point Colocation Method or LPCM) with different polynomial degrees. A one dimensional inclined slider is used for the numerical tests, and the energy equation is artificially decoupled from the Reynolds equation. This approach enables us to focus all the attention on the numerical solution of the energy equation. The results show that the LPCM is one or two orders of magnitude more efficient than the NDM in terms of computation time. The energy equation is then coupled with the Reynolds equation in a thermo-hydrodynamic analysis of the same 1D slider; the numerical results confirm again the efficiency of the LPCM. A thermo-hydrodynamic analysis of a two-lobe journal bearing is then presented as a practical application.


2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 1813-1824 ◽  
Author(s):  
Pentyala Rao ◽  
Birendra Murmu ◽  
Santosh Agarwal

This paper presents the theoretical analysis of comparison of porous structures on the performance of a slider bearing with surface roughness in micropolar fluid film lubrication. The globular sphere model and Irmay?s capillary fissures model have been subject to investigations. The general Reynolds equation which incorporates randomized roughness structure with Stokes micropolar fluid is solved with suitable boundary conditions to get the pressure distribution, which is then used to obtain the load carrying capacity. The graphical representations suggest that the globular sphere model scores over the Irmay?s capillary fissures model for an overall improved performance. The numerical computations of the results show that, the act of the porous structures on the performance of a slider bearing is improved for the micropolar lubricants as compared to the corresponding Newtonian lubricants.


1973 ◽  
Vol 95 (2) ◽  
pp. 187-194 ◽  
Author(s):  
A. Seireg ◽  
H. Ezzat

The classical hydrodynamic theory of fluid film lubrication as described by Reynolds’ equation assumes isothermal conditions in the film. Such conditions may never exist in many engineering applications. A common practice is to calculate bearing performance with isothermal conditions at an average film temperature. This paper presents results on the load-carrying capacity of the film when thermal homogeneity does not exist. An empirical procedure is proposed for the prediction of the thermohydrodynamic behavior of the film. A hysteresis-type phenomenon in the pressure-temperature relationship is also observed.


Author(s):  
Luca Bertocchi ◽  
Matteo Giacopini ◽  
Antonio Strozzi ◽  
Mark T. Fowell ◽  
Daniele Dini

A mass-conserving formulation of the Reynolds equation has been recently developed using the concept of complementarity [1]. The mathematical derivation of the Linear Complementarity Problem (LCP) implemented in the solver favoured in [1] overcomes the drawbacks previously associated with the use of such complementarity formulations for the solution of cavitation problems in which reformation of the liquid film occurs. In the present paper, the proposed methodology, already successfully applied to solve textured bearing and squeeze problems in the presence of cavitation in a one dimensional domain and for incompressible fluids [1], has been extend to a two dimensional domain and the fluid compressibility has been included in the formulation. The evolution of the cavitated region and the contact pressure distribution are studied for a number of different configurations. Some of the results obtained with the proposed scheme are critically analysed and compared with the predictions obtained using alternative formulations (including full CFD calculations). The stability of the proposed algorithm and its flexibility in terms of the implementation of different compressibility laws is highlighted.


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