scholarly journals Thermodynamics and Stability Analysis of High-Speed Hydrodynamic Journal Bearing

2017 ◽  
Author(s):  
Guang Zhu ◽  
Hong Guo ◽  
Ruizhen Li
Keyword(s):  
Stability Analysis ◽  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Journal Bearing

Linear stability analysis of finite hydrodynamic journal bearing under turbulent lubrication with coupled-stress fluid

2016 ◽  
Vol 68 (3) ◽  
pp. 386-391 ◽  
Author(s):  
Abhishek Ghosh ◽  
Sisir Kumar Guha
Keyword(s):  
Stability Analysis ◽  
Newtonian Fluid ◽  
High Speed ◽  
Journal Bearing ◽  
Slenderness Ratio ◽  
Linear Perturbation ◽  
Content Type ◽  
Hydrodynamic Journal Bearing ◽  
The Stability ◽  
Coupled Stress

Purpose Several researchers have observed that to satisfy modern day’s need, it is essential to enhance the characteristics of journal bearing, which is used in numerous applications. Moreover, the use of Newtonian fluid as a lubricant is diminishing day by day, and the use of Non-Newtonian fluids is coming more into picture. Furthermore, if turbo-machinery applications are taken into account, then it can be seen that journal bearings are used for high speed applications as well. Thus, neglecting turbulent conditions may lead to erroneous results. Hence, this paper aims to present focuses on studying the stability characteristics of finite hydrodynamic journal bearing under turbulent coupled-stress lubrication. Design/methodology/approach First, the governing equation relevant to the problem is generated. Then, the dynamic analysis is carried out by linear perturbation technique, leading to three perturbed equations, which are again discretized by finite difference method. Finally, these discretized equations are solved with the help of Gauss-Seidel Iteration technique with successive over relaxation scheme. Consequently, the film response coefficients and the stability parameters are evaluated at different parametric conditions. Findings It has been concluded from the study that with increase in value of the coupled-stress parameter, the stability of the journal may increase. Whereas, with increase in Reynolds number, the stability of the journal decreases. On the other hand, stability increases with increasing values of slenderness ratio. Originality/value Researches have been performed to study the dynamic characteristics of journal bearing with non-Newtonian fluid as the lubricant. But in the class of non-Newtonian lubricants, the use of coupled-stress fluid has not yet been properly investigated. So, an attempt has been made to perform the stability analysis of bearings with coupled-stress fluid as the advanced lubricant.

Three-dimensional computational fluid dynamic analysis of high-speed water-lubricated hydrodynamic journal bearing with groove texture considering turbulence

2021 ◽  
pp. 135065012199851
Author(s):  
Huihui Feng ◽  
Shuyun Jiang ◽  
Yanqin Shang-Guan
Keyword(s):  
Computational Fluid Dynamic ◽  
High Speed ◽  
Journal Bearing ◽  
Fluid Dynamic ◽  
Load Capacity ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Computational Fluid Dynamic Analysis ◽  
Hydrodynamic Journal Bearing ◽  
Groove Texture

Water-lubricated bearings have attracted increasing attention in the field of high-speed machine tools for their low friction due to low viscosity. However, new problems, in particular, insufficient load capacity, are on the way. To the point, groove-textured journal bearing is adopted in this study. Aiming at investigating the effects of groove texture on high speed, water-lubricated, hydrodynamic journal bearing precisely, and thoroughly, three-dimensional computational fluid dynamic analyses considering cavitation and turbulence are undertaken to assess the tribological performances of the bearing. To reduce the amount of three-dimensional modeling and meshing work, mesh deformation is presented. The numerical results are compared with experiments to verify the validity of the present models and calculation procedures. Pressure distribution, load capacity, and friction of groove-textured water-lubricated journal bearing are analyzed with respect to operating conditions and geometric parameters. Comparisons between groove-textured water-lubricated journal bearing and smooth bearing are carried out to find out the influence of groove texture. It is found that the groove texture can achieve a remarkable improvement of load capacity at a smaller eccentricity ratio and higher rotary speed. The load capacity is affected by the combined effects of groove depth, width, and length. However, generally, the friction force of water-lubricated journal bearing is slightly influenced by groove texture. Results can provide theoretical guidance for the optimal design of groove-textured water-lubricated journal bearing under different operating parameters.

Theoretical and Experimental Determination of the Dynamic Characteristics of a Hydrodynamic Journal Bearing

1979 ◽  
Vol 101 (2) ◽  
pp. 129-137 ◽  
Author(s):  
D. W. Parkins
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Previous History ◽  
Relative Magnitude ◽  
Data Logging ◽  
Linear Gradient ◽  
High Speed Data ◽  
Zero Values ◽  
Hydrodynamic Journal Bearing

This paper describes a theoretical and experimental investigation into the nonlinear characteristics of the eight coefficients which specify the lateral flexibility of a hydrodynamic journal bearing. Coefficient calculations allowed viscosity to vary with temperature, and pressure, and examined a range of positive and negative displacements and velocities. Experimental techniques have been developed in which coefficients were deduced from specially chosen, imposed vibration orbits arising from two mutually perpendicular external oscillating forces of variable relative magnitude and phase. Journal centre displacement and velocity were measured using high speed data logging equipment. Coefficients are defined in terms of a “zero” value and linear gradient. Using realistic criteria, measured coefficient non-linearity was found to be significant at eccentricity ratios greater than 0.78. Theory adequately predicted some “zero” values but not gradients. An improvement in the coefficient prediction may depend on the inclusion of some previous history dependent factors.

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