An Analysis of the Steady State and Dynamic Characteristics of a Spherical Hydrodynamic Journal Bearing

1989 ◽  
Vol 111 (3) ◽  
pp. 459-467 ◽  
Author(s):  
P. S. Leung ◽  
I. A. Craighead ◽  
T. S. Wilkinson

With recent developments in N. C. manufacturing processes it is relatively straightforward to produce a journal bearing with spherical surfaces. Such a bearing offers two main advantages over a conventional bearing: it can tolerate much larger misalignment and it can resist axial forces. In this paper, the steady state performance of a spherical journal bearing is studied by using a finite bearing theory. The dynamic characteristics of the bearing are represented by eight displacement and velocity force coefficients and the boundary of bearing stability is determined. The effect of superlaminar flow upon the bearing performance is also studied, and typical bearing design charts are provided. In comparison, the behavior of the spherical journal bearing is found to be similar to that of an equivalent cylindrical bearing.

Author(s):  
Sanjay Sharma ◽  
Gourav Jamwal ◽  
Rajeev K Awasthi

In the present study, the optimum design parameters of chevron-shaped surface texture have been determined for the steady state performance enhancement of a hydrodynamic journal bearing. The fluid flow governing Reynolds equation has been solved using the finite element method, assuming iso-viscous and Newtonian fluid to obtain the static performance characteristics of textured hydrodynamic journal bearing. Different texture depths, areas and distributions have been numerically simulated and a set of optimum texture parameters has been determined based on the maximum performance enhancement ratio. The numerically obtained results indicate that surface texturing can improve bearing performance if the textured region is placed in the pressure build-up region. Moreover, surface texturing is the most effective at bearing performance enhancement when the bearing operates at lower eccentricity ratios. The performance enhancement ratio, which is the ratio of load-carrying capacity to coefficient of friction is found to be maximum at texture depth of 0.4, k = 0.3, textured zone located in the increasing pressure region and eccentricity ratio of 0.2.


Author(s):  
M Malik

A new type of gas-lubricated floating-ring journal bearing in which the fixed bearing and the ring are both porous, has been conceived and analysed, theoretically, for the steady state characteristics. Bearing characteristics are presented against two design parameters, namely, clearances ratio and permeability parameter. The comparison of these characteristics with those of externally-pressurized plain porous journal bearings shows that the new bearing represents, with its steady state performance, a distinctly advanced bearing design.


2004 ◽  
Vol 47 (4) ◽  
pp. 480-488 ◽  
Author(s):  
Keith Brockwell ◽  
Waldemar Dmochowski ◽  
Scan Decamillo

Author(s):  
Ashutosh Kumar ◽  
Sashindra Kumar Kakoty

Steady-state and dynamic characteristics of two-lobe journal bearing, operating on TiO2 based Nano-lubricant has been obtained. The effective viscosity is obtained by using Krieger-Dougherty viscosity model for a given volume fraction of nanoparticle in the base fluid. Various bearing performance characteristics are then obtained by solving modified Reynolds equation for variable viscosity model and couple stress model. The stiffness and damping coefficients are also determined for various values of the volume fraction of the nanoparticle in the nanofluid. Results reveal that load carrying capacity and flow coefficient increase whereas friction variable decreases without affecting the stability condition of two-lobe journal bearing operating on TiO2 based nanolubricant. On the other hand attitude angle and dynamic coefficients remains constant for all the values of volume fraction of nanoparticle.


2019 ◽  
Vol 71 (9) ◽  
pp. 1055-1063 ◽  
Author(s):  
Sanjay Sharma ◽  
Gourav Jamwal ◽  
R.K. Awasthi

Purpose The purpose of this paper is to provide the various steady state parameters of hydrodynamic journal bearings have been determined to get maximum performance enhancement ratio. For this, the bearings inner surface is textured with triangular shape with different texture depths and a number of textures in pressure increasing region. The textured region acts as a lubricant reservoir, which provides additional film-thickness and reduce friction. Therefore, enhance the overall performance of bearing. Design/methodology/approach In the present study, the effect of triangular shaped texture on the static performance characteristics of a hydrodynamic journal bearing has been studied. Different values of texture depths and a number of textures have been numerically simulated in pressure developing region. The static performance characteristics have been calculated by solving the fluid flow governing Reynolds equation using the finite element method, assuming iso-viscous Newtonian fluid. The performance enhancement ratio, which is the ratio of load carrying capacity (LCC) to the coefficient of friction (COF) has been calculated from results to finalized optimum design parameters. Findings The paper provides numerically obtained results indicate that surface texturing can improve bearing performance if the textured region is placed in the pressure increasing region. Moreover, surface texturing is the most effective at bearing performance enhancement when the bearing operates at lower eccentricity ratios and texture depth. The performance enhancement ratio, which is the ratio of LCC to the COF is found to be a maximum value of 2.198 at texture depth of 1.5, eccentricity ratio of 0.2 and the textured region located in the increasing pressure region. Research limitations/implications The present study is based on a numerical based research approach, which has its limitations. So, researchers are encouraged to investigate the same work experimentally. Practical implications The paper includes implications to be beneficial for designers for designing better hydrodynamic journal bearings. Originality/value For the triangular shaped texture, considered in the present study, the optimum values of texture depth and texture distribution region have also been determined. While designing, designers should focus on those values of texture depth, texture region and a number of textures, which give the maximum value of performance enhancement ratio, which represents maximum LCC at the lowest value of the COF.


1984 ◽  
Vol 106 (1) ◽  
pp. 54-60 ◽  
Author(s):  
S. M. Metwalli ◽  
G. S. A. Shawki ◽  
M. O. A. Mokhtar ◽  
M. A. A. Seif

A novel approach is presented to optimize the finite journal bearing performance under steady loading conditions. Closed form expressions representing the behavior of the bearing as explicit functions of the design variables are utilized. Different competing objectives are assumed to suit various design applications. A method of multiplying objectives and raising to different exponents has been adopted. The basic competing objectives are minimum power loss, maximum-minimum film thickness, minimum side leakage, minimum temperature rise, and minimum bearing size. A journal bearing design procedure for optimum performance is thus devised for the selection of optimum bearing length, clearance, and oil viscosity. A numerical example is also presented.


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