Currently, the herringbone groove journal bearing (HGJB) has important applications in miniature rotating machines such as those found in the computer information storage industry. Grooves scribed on either the rotating or stationary member of the bearing pump the lubricating fluid inward thus generating support stiffness and improving its dynamic stability when operating concentrically. The narrow groove theory (NGT), traditionally adopted to model the concentric operation of these bearings, is limited to bearings with a large number of grooves. A finite element analysis is introduced for prediction of the static and rotordynamic forced response in HGJBs with finite numbers of grooves. Results from this analysis are then compared to available experimental data as well as to estimates from the NGT. A bearing geometry parametric study is then conducted to determine optimum rotordynamic force coefficients. A discussion on the temporal variation of the bearing reaction forces and force coefficients for a rotating journal with a small number of grooves is also presented. These changes can be significant at high operating eccentricities, possibly inducing a parametric excitation in rotating systems employing this type of bearing.

Finite element analysis of herringbone groove journal bearings : A parametric study

\n This paper offers an extensive review of publications dealing with the modeling, the design, and the experimental investigation of grooved dynamic gas-lubricated bearings. Recent years have witnessed a rise in small-scale and high-speed turbomachinery applications. Besides the well-known gas foil bearings, grooved bearings offer attractive advantages, which unveil their potential in particular at small scale due to the structural simplicity as well as satisfying predictability. This paper starts with a general background of the application of gas-lubricated bearings and introduces and compares the different gas bearing topologies. Further, the state-of-the-art modeling of grooved gas-lubricated bearings is introduced, systematically assessing the advantages and inconveniences of two major approaches, i.e., the narrow groove theory (NGT) and direct discretization method. Since the NGT method is an elegant and efficient approach to model the complex effects of periodic grooves, a critical section is dedicated to the NGT. In a second phase, different models to include additional physical phenomena such as real gas lubrication, rarefaction, or turbulence effects are reviewed. The paper concludes with a critical assessment of the state-of-the-art and indicates potential fields of research that would allow to shed more light into the understanding of these bearings, as well as with some thoughts on the integrated design methodologies of gas bearing supported rotors.

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A Review of Grooved Dynamic Gas Bearings

Recently, herringbone-grooved journal bearings have had important applications in miniature rotating machines. The scribed grooves, on either the rotating or stationary member of the bearing, can pump the lubricant inward, which generates supporting stiffness and improves the dynamic stability, especially for concentric operation. Most of the previous investigations that dealt with herringbone grooved journal bearings and grooved thrust bearings were theoretical. Few experimental attempts for the investigation of the performance characteristics of herringbone grooved journal bearings (HGJBs) and grooved thrust bearings have been done. All these investigations concentrated on rectangular and circular groove profiles of HGJBs. In order to improve the performance characteristics of HGJBs, a new design of the groove profile, the beveled-step groove profile, is introduced. The introduced groove profile is capable of increasing the pressure recovery at the divergence of the flow over the step. In addition, it increases the amount of oil pumped inward over the circular groove profile. Optimization processes were carried out experimentally, in order to obtain the optimal geometry of the introduced groove profile. The optimum geometrical parameters of the groove (groove angle a, groove width ratio β, and groove depth ratio T) are 29 deg, 0.5, and 2.0, respectively, which give maximum radial force and maximum radial stiffness of the beveled-step HGJB. In order to check the effectiveness of the introduced beveled-step groove profile, the obtained results were compared with that for rectangular groove profile. The comparison shows that the introduced beveled-step HGJBs have higher radial force, higher load carrying capacity, and lower friction torque than the rectangular HGJBs.

On the Optimum Groove Geometry for Herringbone Grooved Journal Bearings

Solving elastohydrodynamic lubrication (EHL) problems is a complex and time-consuming process due to the interactive solutions of the Reynolds equation and contact elasticity. Analyzing journal bearing EHL problems is even more difficult due to the scale difference in the structural and surface features, which may span four orders of magnitude. This article presents a fast EHL computing technology utilizing a parallel numerical iterative method (the red–black successive overrelaxation method) and multithreaded computing scheme conducted by OpenMP directives. The fast computational approaches allow the construction of high-density EHL meshes for effective descriptions of important texture features of journal bearing surfaces.

Exploration on a Fast EHL Computing Technology for Analyzing Journal Bearings with Engineered Surface Textures

Effect of support stiffness and damping on stability characteristics of herringbone-grooved aerodynamic journal bearings mounted on viscoelastic supports

C. Y. Chow

Papers

Helical-Grooved Journal Bearing Operated in Turbulent Regime