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This study aims to deal with the performance of symmetric/asymmetric slot entry hybrid journal bearing system considering the effect of three dimensional irregularities in the analysis.

The asperity profile of three-dimensional irregularities has been modeled in both circumferential and axial directions. To compute the bearing performance characteristics parameter, finite element formulation of governing Reynolds equation has been derived using Galerkin’s technique.

Based on the numerically simulated results, it has been observed that the three-dimensional irregularities enhance the value of minimum fluid film thickness (h̄_min), lubricant flow (Q̄) and fluid film damping coefficients (C̄₁₁,C̄₂₂) approximately by order of magnitude of 24-26, 43-51 and 18-66 per cent, respectively, for the case of asymmetric slot entry configuration. Whereas, the values of fluid film stiffness coefficients (S̄₁₁,S̄₂₂) and threshold speed (ω̄_th) reduces approximately by order of 1-6 and 0-3 per cent, respectively, for the case of symmetric slot entry configuration.

The present paper describes that the influence of three-dimensional irregularities on bearing surface on the performance of slot entry hybrid journal bearing is original in literature gaps. The numerically simulated results presented in this study are expected to be quite useful to the bearing designers.

This paper is supposed to provide a critical review of current research progress on thermal management in grinding of superalloys, and future directions and challenges. By understanding the current progress and identifying the developing directions, thermal management can be achieved in the grinding of superalloys to significantly improve the grinding quality and efficiency.

The relevant literature is collected from Web of Science, Scopus, CNKI, Google scholar, etc. A total of 185 literature is analyzed, and the findings in the literature are systematically summarized. In this case, the current development and future trends of thermal management in grinding of superalloys can be concluded.

The recent developments in grinding superalloys, demands, challenges and solutions are analyzed. The theoretical basis of thermal management in grinding, the grinding heat partition analysis, is also summarized. The novel methods and technologies for thermal management are developed and reviewed, i.e. new grinding technologies and parameter optimization, super abrasive grinding wheel technologies, improved lubrication, highly efficient coolant delivery and enhanced heat transfer by passive thermal devices. Finally, the future trends and challenges are identified.

Superalloys have excellent physical and mechanical properties, e.g. high thermal stability, and good high-temperature strength. The superalloys have been broadly applied in the aerospace, energy and automobile industries. Grinding is one of the most important precision machining technologies for superalloy parts. Owing to the mechanical and physical properties of superalloys, during grinding processes, forces are large and a massive heat is generated. Consequently, the improvement of grinding quality and efficiency is limited. It is important to conduct thermal management in the grinding of superalloys to decrease grinding forces and heat generation. The grinding heat is also dissipated in time by enhanced heat transfer methods. Therefore, it is necessary and valuable to holistically review the current situation of thermal management in grinding of superalloys and also provide the development trends and challenges.

The slot-entry hybrid journal bearings have been successfully used in various engineering applications because of their good performance over wide range of speed and load, besides their relative simplicity in manufacturing. Most of the research work pertaining to non-recessed journal bearing assumes standard symmetric and asymmetric configurations. However, many more configurations are possible by changing the position of slot which may improve the performance of the slot-entry journal bearing. In the present work study of static performance characteristics of slot-entry journal bearing of different configuration has been carried out. The paper aims to discuss these issues.

FEM has been used to solve the Reynolds equation governing the flow of lubricant in the bearing clearance space along with the restrictor flow equation. The non-Newtonian lubricant has been assumed to follow the cubic shear stress law. The performance characteristics of slot-entry hybrid journal bearings are computed by developing a computer program.

The simulated results of bearing characteristics parameters in terms of minimum fluid-film thickness and bearing flow have been presented for the wide range of various values of non-linearity factor and external load. It is found that there is an increase in the oil requirement for slot-entry hybrid journal bearing with the specified operating and geometric parameters, when the viscosity of the lubricant decreases due to the non-Newtonian behavior of the lubricant. The effect of the decrease in the viscosity of the lubricant due to non-Newtonian behavior of the lubricant diminishes the attitude angle. The computed performance characteristics are helpful for the bearing designer while choosing a particular configuration of bearing.

The performance characteristics have been computed by considering the non-Newtonian lubricants. The thermal effects have been ignored in the analysis so as to obviate the mathematical complexity.

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Hybrid bearings have found increasing applications in various machines owing to their large number of favorable characteristics like high load carrying capacity, increased minimum fluid film thickness, long life and increased damping making them attractive for various applications such as turbo machinery, machine tool spindles, precision grinder spindles, etc. A careful design of such bearing for optimum performance has always been among the key issues of the researchers. The present work has been carried out to study the effect of bearing geometric parameters on performance of hybrid journal bearing and supply cut‐off behavior has also been studied for the improved performance.

The generalized Reynold's equation governing the fluid flow in the clearance space between bearing and journal has been solved using finite element method to determine the pressure distribution, subsequently performance of hole‐entry hybrid journal bearing are computed. The journal centre equilibrium position for the given load is computed and the formulation is explained. The geometric parameters include aspect ratio, land width ratio, number of rows and number of holes per row. Further, performance of the bearing is computed with increasing the load, which induces negative pressure or the backpressure at the supply holes subsequently those are plugged to support the higher load.

The obtained results are presented in graphical form and logical conclusions are drawn and the modified configurations with reduced number of holes are suggested for higher load. It is observed that the bearing configuration with aspect ratio = 1.0 and land width ratio = 0.2 is best for high load support for low power requirement as less lubricant is required to be pumped in the bearing yet it provides sufficient fluid film thickness and lower values of maximum pressure. The load carrying capacity of the bearing can be further increased by plugging the holes on which backpressure is obtained for same bearing configuration. A feedback control with hybrid bearing system will sustain the sudden increase of load by shutting off the supply of the lubricant through supply hole where negative pressure is encountered.

The paper addresses the performance of non recessed hybrid journal bearings with wide range of geometric parameter. The results are quite useful for the bearing designer. The supply cut‐off is another aspect of originality of the paper as it provides the better load support.

The present work aims to predict accurately the bearing design data for non‐recessed hybrid journal bearings, considering the effect of non‐Newtonian behavior of lubricant for different symmetric and non‐symmetric bearing geometric configurations.

The simultaneous solution of generalized Reynold's equation governing the laminar flow of incompressible lubricant and the equation of flow of lubricant through the capillary restrictor, considering variable viscosity of lubricant following the “Power law”, has been carried out using FEM. For a given set of bearing geometric, operating parameters and for given external vertical load, the values of various performance characteristics have been obtained for a range of values of power law index, after establishing the journal center equilibrium position, the analysis for which has been elaborately explained.

The results obtained have been presented graphically for various bearing performance characteristics. It has been observed that with decrease in power law index “n”(0<n≤1), the value of h¯_min and load carrying capacity decreases, while bearing flow rate increases for all configuration. The load‐carrying capacity of asymmetric configurations is better and stable over entire range of restrictor design parameter. Bearing configuration with land width ratio = 0.25 and aspect ratio = 1.0, having two rows of holes and six holes in each row, will be better suited for high‐load support, as it has maximum value of minimum fluid film thickness, moderate value of bearing flow and value of attitude angle is almost constant.

The performance characteristics of journal bearing have been presented for a wide range of values of power law index and for different values of restrictor design parameter for capillary restrictor, after establishing the journal center equilibrium position. The comparison of the different symmetric and non‐symmetric journal‐bearing configurations to find the best geometric configuration at different operating conditions, considering the effect of non‐Newtonian behavior of lubricant, represents the originality of the work.

Investigates rotation effects on hybrid plain journal bearings with various feeding mechanisms, i.e. orifice, capillary and porous feedings. Employs the numerical method of the finite difference to solve Reynolds equations. Shows that higher speed of rotation induces greater hydrodynamic load capacity, especially with an eccentricity ratio ε > 0.85. The porous and orifice feedings also result in higher load capacity than orifice and capillary feedings when the rotation speeds increase. Also analyses the multi‐array of hole‐entry of orifice and capillary feedings and the results show that the bearings with more arrays of feedings produce higher load capacity at low speed. However, the bearings with fewer arrays of feedings produce higher load capacity at high speeds. In other words, the transition from the hydrostatic to hydrodynamic load capacity of the bearing is significant to hybrid plain journal bearings.

To provide an up‐to‐date review and design guide for industry users and designers of hydrostatic fluid film journal bearings.

Detailed study and review of published works dating from 1965 to 2004. Comments and comparisons made on findings and ease of use for each. Design guide study summarised in outline form showing relationships and interdependencies of dimensions and parameters.

Some previous design recommendations difficult to use owing to errors, ambiguous use of symbols and undefined terms. Terms are frequently interchanged without definition, sometimes in the same paper. Many works difficult and time‐consuming to retrieve and study without access to comprehensive technical library archives.

Work indicated that more evaluation and practical study may be needed for full study. Guideline approach useful for busy designers to help lead understanding through more detailed works available.

A very useful outline summarising the key features of hydrostatic bearings and the relationships between performance and key design parameters and dimensions. A good introduction for designers embarking on a new bearing design or needing to specify an application.

Encapsulates a widely varied and published field with appropriate cautionary commentary on uses and abuses of current design guides.

This paper emphasises the importance of designing bearings for minimum power dissipation and temperature rise. Criteria are given which enable a designer to arrive at optimum values of any parameter for his particular bearing application.

The aim of the present paper is to study the combined influence of textured surface and micropolar lubricant behaviour on the performance of two-lobe hole-entry hybrid journal bearing system. The bearing performance parameters of the textured circular/two-lobe hole-entry hybrid journal bearing system have been computed against the constant vertical external load supported by the bearing.

In this work, Eringen’s micropolar fluid theory has been used to derive the governing Reynolds equation. The consequent solution of the governing Reynolds equation has been obtained by using finite element method (FEM) numerical technique.

The present study indicates that the use of the textured surface, two-lobe profile of bearing and micropolar lubricant, significantly enhances the bearing performance as compared to non-textured circular journal bearing.

The present study concerning the influence of surface texturing on the behaviour of the two-lobe hole-entry hybrid journal bearing lubricated with micropolar lubricant is original. The theoretically simulated results of the present study will be useful to design an efficient journal bearing system.

Hole‐entry hybrid journal bearings are widely used in many applications owing to their favourable characteristics. Ever increasing technological developments demand much improved performance from these class of bearings operating under the most stringent, exact and precise conditions. Therefore, it becomes imperative that the hole‐entry journal bearings be designed on the basis of more accurately predicted bearing characteristics data. The purpose of this paper is to describe a theoretical study to demonstrate the combined influence of the effect of pocket size at the outlet of supply holes and the journal misalignment on the performance of an orifice compensated hole‐entry hybrid journal bearing system.

Finite element method is used to solve the Reynolds equation governing the flow of an incompressible lubricant in the clearance space between the journal and bearing together with equation of flow through an orifice. The journal misalignment has been accounted for by defining a pair of misalignment parameters sigma and delta. The effect of pocket size at the outlet of supply holes has been accounted by defining a non‐dimensional parameter which is function of diameter of pocket and journal diameter.

The results presented in this paper indicate that the effect of journal misalignment is, in general, to cause a reduction in bearing dynamic characteristics parameters whereas the effect of pocket size is to slightly compensate this loss. Performance of a two lobe four recessed journal bearing, a proper selection of bearing offset factor along with type of restrictor (capillary or orifice) is essential.

This paper presents valuable data relating to hole‐entry hybrid journal bearings useful for bearing designers.