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Constant flow valves have been presented in industrial applications or academic studies, which compensate pressures of bearing recesses as load fluctuates. The flow rate of constant-flow valves (CFVs) can be constant in spite of the pressure changes in recesses. However, specific condition of design parameters must be satisfied. The paper aims to discuss these issues.

This paper utilizes analytical method to study the static characteristics of CFVs, three types belong to traditional design of CFV are reviewed afresh. Moreover, an innovative design for constant flow is presented and studied.

The review and study results reveal that appropriate relationships among design parameters for these types of CFVs.

The numerical simulation is used to investigate the influence of design parameters on the change of flow rate when pressure ratio of recess is changed.

This paper aims to describe how successfully a particular restrictor delivers its best in increasing the conical journal bearing performance. The restrictors are used in the hole-entry conical journal bearing subjected to hybrid mode. Thus, the restrictors, like constant flow valve (CFV), orifice and capillary, are studied comparatively.

Numerical simulation for the bearing results with the three restrictors are obtained by using finite element method (FEM) under the well-known modified Reynolds equation.

When the hole-entry conical journal bearings, with the restrictor design parameter range C¯_s2 = 0.03 – 0.09, are operated, the results obtained are quite distinctive and significant. It indicates that the CFV restrictor-based conical bearing gives enhanced performance in comparison to orifice and capillary restrictors. Moreover, it suggests the performance-wise sequence of the restrictors in hybrid bearings as CFV > Orifice > Capillary.

The outcome of the research paper will give insight to help the bearing designer to choose the particular restrictor in hybrid conical bearing depending on the industrial need.

An electrorheological (ER) fluid comprises dielectric particles suspended in an insulating viscous medium. ER lubricants are considered smart lubricants. They have been applied in hydraulic valves, power transmission devices and damping systems. The purpose of this study is to investigate the performance of hydrostatic thrust bearing operating with ER lubricant.

Reynold’s equation was used to model the flow of the ER lubricant in the bearing. The continuous Bingham model was used to express the viscosity of the ER lubricant as a function of yielding stress, applied electric field and shear strain rate. The Reynolds equation is solved using the finite element method (weighted residual approach) to compute the film pressure as a primary variable and the lubricant flow rate, load-carrying capacity, stiffness and damping parameters as associated performance indices.

The effects of the pocket shape, compensating elements and ER lubricant on the bearing performance were investigated. The application of ER lubricant significantly enhanced the load-carrying capacity (48.2%), stiffness (49.8%) and damping (4.95%) of the bearings. Circular and triangular pocket bearings with constant-flow valves have been reported to provide better steady-state and rotor-dynamic performances, respectively.

This study presents the effect of an ER lubricant on the rotor-dynamic performance of hydrostatic thrust bearings with different pocket shapes.

The changing technological scenario necessitated hybrid journal bearings to operate under severe conditions of heavy load and high speed resulting into temperature rise of the lubricant fluid-film and bearing surface. To predict the performance of a bearing realistically, theoretical model must consider the combined influence of the rise of temperature and non-Newtonian behavior of the lubricant. The aim of the present paper is to study the effect of viscosity variation due to temperature rise and non-Newtonian behavior of the lubricant on performance of constant flow valve compensated multiple hole-entry hybrid journal bearings.

Finite element method has been used to solve Reynolds equation along with restrictor flow equation, 3D energy equation and 3D conduction equation using suitable iterative technique. The non-Newtonian lubricant has been assumed to follow cubic shear stress law.

The thermohydrostatic rheological performances of symmetric and asymmetric hole-entry hybrid journal bearing configurations are studied. The computed results illustrate that variation of viscosity due to rise in temperature and non-Newtonian behavior of the lubricant affects the performance of hole-entry hybrid journal bearing system quite significantly.

In the present work, the influences of the viscosity variation due to temperature rise and non-Newtonian behavior of the lubricant on the performance characteristics of non-recessed hole-entry hybrid journal bearing with symmetric and asymmetric configurations compensated with constant flow valve restrictors have been investigated for generating the design data to be used by bearing designer. The design data computed in the present thesis are a contribution in field of knowledge of bearing design.

This paper aims to investigate the effect of plugging of holes on the static performance characteristics of a constant flow valve compensated hole‐entry hybrid journal bearing system operating with Newtonian and non‐Newtonian lubricants. The analysis considers the generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor. The non‐Newtonian lubricant is assumed to follow the power law. The performance characteristics are computed for the two values of power law index (n=1.0 and 0.566). The computed results indicate that the blockage of holes during operation will not be the likely causes for the imminent failure of a well‐designed non‐recessed hole‐entry hybrid journal bearing.

Finite element method has been used to solve generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor.

The computed results indicate that the blockage of holes during operation will not be the likely causes for the imminent failure of a well‐designed non‐recessed hole‐entry hybrid journal bearing. The bearing configuration with plugged holes provides sufficient fluid film thickness and low power requirement as less lubricant is required to be pumped in the bearing.

To the best of the author's knowledge, no study which considers the influence of plugging of holes on the static performance characteristics of a constant flow valve compensated hole‐entry hybrid journal bearing system operating with Newtonian and non‐Newtonian lubricant is yet available in the literature.

This paper aims to describe the theoretical study concerning the effect of non‐linear behavior of the lubricant on the performance of symmetric constant flow valve compensated hole‐entry hybrid journal bearing. The bearing performance characteristics have been computed for various values of non‐linearity factor, land width ratio, aspect ratio and external load.

The analysis considers the generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor. The non‐Newtonian lubricant is assumed to follow the cubic shear stress law.

The study indicates that for generation of accurate bearing characteristics data, the inclusion of non‐linear effects of lubricant in the analysis is essential.

The performance characteristics in terms of minimum fluid‐film thickness, fluid‐film stiffness and damping coefficients, critical mass and threshold speed for a wide range of values of the non‐linearity factor and external load are presented. The results presented are expected to be quite useful to bearing designers.

Hybrid journal bearing have long been used in machines requiring large load and high speed capacity operating under wide range of temperatures. Different compensating devices are used in for efficient operation of bearings. This paper aims to help in selection of optimum compensating device by evaluating the comparative performance of constant flow valve, capillary compensated and slot entry hybrid journal bearing under the combined influence of thermal effects and micropolar nature of lubricant.

The variation in micropolar parameters and viscosity change due to temperature increase of lubricant are considered in present study. Finite element method is used for combined iterative solution of micropolar Reynolds, energy and conduction equations. Micropolar lubricant is assumed to be governed by two parameters, coupling number and characteristic length. The results in the study are presented for symmetric and asymmetric configurations of hole entry and slot entry non-recessed hybrid journal bearings

The results indicate that constant flow valve compensated hole entry hybrid journal bearing is the highest performing bearing for the given range of micropolar parameters of lubricant in terms of maximum fluid pressure and dynamic coefficients.

The performance variations of various configurations of hybrid journal bearing are presented in a single paper. The reader can get overview of combined effects of micropolar parameters and viscosity decrease due to temperature increase of the lubricant.