Load Carrying Capacity Of Bearing Research Articles

Influence of magneto-hydrodynamic and couple stress squeeze film lubrication on conical bearing-a slip velocity model

This paper explores the impact of MHD couple stress and slip velocity over a conical bearing in the presence of magnetic field. The flow is considered as incompressible. A uniform magnetic field is imposed perpendicular to the bearing alongy-axis. The modified Reynolds equation is solved using appropriate boundary conditions in dimensionless form to find the pressure distribution which is then used to obtain the expression for load carrying capacity paving the way for the calculation of response time. Numerical computations of the results show that the MHD couple stress on the conical bearings indicates that enhances the pressure distribution, load carrying capacity and squeeze film time of the conical bearings. Further, decrease in these characteristics was observed for the increased values of slip velocity and cone angle.

Effect of varying stiffness of top foil on the performance of Air foil thrust bearing (AFTB)

Air foil thrust bearings (AFTB) are essential components in various rotating machinery, such as gas turbines and turbochargers, designed to support higher loads while minimizing friction and wear. The project aims to investigate the effect of varying stiffness of the top foil on the performance of air foil thrust bearings. The stiffness of the top foil is a critical parameter that influences the bearing's load-carrying capacity, stability, and overall efficiency. The geometric parameters like foil geometry, sector angle of top foil, initial angle of top foil and thickness of top foil and operating parameters like runner speed, gap between top foil and runner, will affect the load carrying capacity of the thrust bearing. The study involves both static analysis and dynamic analysis to comprehensively evaluate how changes in top foil stiffness affect the bearing's operational characteristics. The geometric parameters like foil geometry, sector angle of top foil, initial angle of top foil and thickness of top foil are considered for the study. The results of these analyses will be used to validate how the varying geometrical parameters impact the stiffness of the Air foil thrust bearing. This will provide practical insights into the real-world performance of air foil thrust bearings with varying top foil stiffness. The findings of this research will have significant implications for the design and optimization of air foil thrust bearings in various industrial applications. By understanding how changes in top foil stiffness affect the bearing's performance, engineers and researchers can enhance the efficiency and reliability of rotating machinery, ultimately contributing to improved energy efficiency and reduced maintenance costs.

Parametric optimisation on the performance of the journal bearing using Taguchi approach

Hydrodynamic journal bearings are widely used to support high-speed rotating equipment due to their excellent strength and load-bearing capacity. Therefore, bearings are essential mechanical elements to improve the quality of rotating equipment. Bearing performance depends on various factors but pressure and frictional torque plays a vital role in load carrying capacity of bearing. In this present work, both experimental and analytical approach of a typical journal bearing has been carried out to determine the optimal performance of the bearing. Taguchi-based optimisation method has been proposed for journal bearing. Taguchi L27 orthogonal array has been planned to study peak pressure and frictional torque with three input parameters speed, load and viscosity index. The result shows that loading criterion influences much on performance of bearing. The experimental data is obtained from a journal bearing test rig and the analytical data are generated by MINITAB 18. From the experiment, it can be confirmed that speed – 2000 rpm, load – 600 N and viscosity index – 150 are the ideal process parameters for lower peak pressure and less frictional torque.

A Fluid-Structure Interaction Method for the Elastohydrodynamic Lubrication Characteristics of Rubber-Plastic Double-Layer Water-Lubricated Journal Bearings

This paper proposes a fluid-structure interaction (FSI) numerical calculation method for investigation of the elastohydrodynamic lubrication performance of the rubber-plastic double-layer water-lubricated journal bearings. The accuracy and rapidity of the FSI method are improved by studying the effect of mesh density and by comparing the calculation results with those in the literature. Based on the proposed method, a series of numerical simulations are carried out to reveal the influence of operating conditions and structural parameters on the lubrication performance of the rubber-plastic bearings. Numerical results show that the bush deformation of the rubber-plastic bearing is between that of the rubber bearing and the plastic bearing, and the deformation area is close to that of the rubber bearing. The bearing load carrying capacity increases significantly with the rotational speed, eccentricity ratio, bearing length, and decrease with the clearance. But the influences of the plastic layer elastic modulus and thickness on bearing load are unremarkable. The effect of bush deformation on bearing load is noticeable when the eccentricity ratio is more than 0.8. The results are expected to provide design references for the bearings.

Numerical and experimental investigation on the performances of a liquid metal bearing with spiral groove structures

Liquid metal is a perfect lubricant due to its low melting point, good fluidity at room temperature, higher thermal conductivity and high temperature stability. In this work, the novel hydrodynamic liquid metal bearing with spiral grooves is studied. Influences of the eccentricity, the bearing radius clearance, and the groove structural parameters on the pressure distributions and the load carrying capacity of journal liquid metal bearing are deeply numerically investigated. Meanwhile, the bearing clearance and the structure parameter of herringbone grooves on pressure distribution and load carrying capacity of thrust liquid metal bearing are also numerically conducted and experimentally validated. Numerical studies are conducted based on the finite element method. Results show that the pressure distribution and the load carrying capacity of journal liquid metal bearing are significantly affected by the eccentricity, the bearing clearance and the groove structural parameters. Specifically, for journal bearing, the load carrying capacity increases with the growth of the eccentricity and the groove spacing, while it decreases with the increase of radius clearance, the groove depth and the groove ridge ratio. Besides, it turns out that when the spiral angle is larger than 37.5 degree, the increase of the groove spiral angle results in a decrease of the load carrying capacity, while when the spiral angle is lower than 37.5 degree, the value of load carrying capacities at different spiral angle depends on the specific value of eccentricity. As for thrust bearing, the load carrying capacity increases with the decrease of bearing clearance, and the increase of groove depth. Besides, the groove numbers of 13 and the angle between two vertices of herringbone groove of 13 degree are beneficial for improving the load carrying capacity of thrust liquid metal bearings. Based on the above observations, optimal design parameter sets are selected to obtain much higher load carrying capacities up to four times for both journal and thrust bearings compared with the bearings with original parameters.

A transfer learning based artificial neural network in geometrical design of textured surfaces for tribological applications

This study aims at introducing the potential to utilise transfer learning methods in the training of artificial neural networks for tribological applications. Artificially enhanced surfaces through surface texturing, as an example, are investigated under hydrodynamic regime of lubrication. The performance of these surface features is assessed in terms of load carrying capacity and friction. A large performance dataset including bearing load carrying capacity and friction is initially obtained for a specific category of textures with rectangular cross-sectional profile through analytical methods. The produced bearing performance are used to train a neural network. This neural network was then trained further by a minimal set of performance measure data from an intended category of textures with triangular cross-sectional profiles. It is shown that the resulting neural network performs with acceptable level of confidence for those intended texture profiles when trained with such relatively low number of performance data points. The results indicate that fast analytical methods can potentially produce a large volume of training datasets, which effectively allows for use of relatively lower number of training data sets from the intended category, where creating data for trainings can be more complex or time consuming. Use of transfer learning method in tribological applications and use of bearing performance parameters, as opposed to bearing design parameters, for training the neural networks are the major novel contributions of this study, which has not hitherto been reported elsewhere.

Effect of texture on hydrodynamic journal bearing performance under starvation lubrication

The effect of texture on tribological properties of journal bearings operating under starvation lubrication conditions is studied in this paper. The P-θ model with mass conservation boundary conditions is used to accurately predict the oil film distribution in the full oil film/starvation region of the textured bearing. The effects of various degrees of starvation lubrication on the tribological performance parameters, such as eccentricity, attitude angle, full film area, and friction coefficient, are discussed in textured bearings. The results show that the effect of texture on the bearing performance is affected by starvation lubrication conditions: (1) The effect severity varied with starvation levels; (2) The texturing still improved the operating performance of the journal bearing in the case of weak starvation; (3) Texturing increased the bearing load carrying capacity and reduced the friction coefficient, improving safety and preventing safety accidents due to oil supply problems.

Influence of pad geometry and method of oil supply on the thermal state of GTE rotor tilting-pad journal bearing

High heat generation in the hydrodynamic wedge is one of the main factors limiting application of pad journal bearings as bearings for rotors of aircraft gas turbine engines. The goal of the research is to study the influence of the oil supply method on the bearing thermal state and to determine the design factors reducing the bearing temperature. The study was carried out with the use of bearings with diameters of 100320 mm with different design of the oil supply: through oil dispensing grooves in the pads, through oil nozzles in the inter-pad space, using lead-in chamfers for the pads, with oil bypass channels. The tasks posed were solved by using volumetric geometric models with the tools of computational fluid dynamics in the ANSYS CFX package in which differential equations describing the model are solved by the finite element method. The patterns of temperature and pressure distribution over the surface of the lower, most loaded bearing pad were obtained for various options of oil supply and different geometry of bearing pads; values of the bearing load carrying capacity, maximum pressure in the working gap, the oil mass flow through the elements of the oil supply; dependences of the bearing static performance on the distance between the shaft and nozzles. Oil supply through oil dispensing grooves made in pads is a factor that negatively affects the bearing thermal state, which is associated with so-called locking of the working gap. It is shown that implementation of oil supply through the space between the pads is more efficient. The use of a lead-in chamfer with plain inserts simplifies oil supply to the working gap. The design solutions described make it possible to reduce the maximum oil temperature in the bearing by 36 degrees Celsius.

Assessing the Potential Replacement of Mineral Oil with Environmentally Acceptable Lubricants in a Stern Tube Bearing: An Experimental Analysis of Bearing Performance

Abstract This study compares the performance of a plain bearing, with a similar structure to a tail shaft stern bearing, lubricated with either mineral oil or an environmentally acceptable lubricant (EAL). The main characteristic of the bearing is its length/diameter ratio of <1. Measurements are carried out with the bearing operating under loads from 0.5 to 1 MPa and seven speeds ranging from 1 to 11 rev/s. The bearing lubricated with either mineral oil with a viscosity grade of 100 or an environmentally acceptable lubricant (EAL) with a viscosity grade of 100 or 150 is investigated according to the ISO standard. Bearing wear is simulated by increasing the clearance circle by 0.1 mm. According to the results obtained, the use of an EAL in place of mineral oil does not cause significant changes in the bearing performance, regardless of the value of the clearance radius. The pressure distribution in the oil film, bearing load carrying capacity, eccentricity and friction coefficient have similar values for the entire load and speed ranges considered, and the discrepancies in the results are within the range of the measurement errors. Only an increase in EAL viscosity causes significant changes in bearing performance and these changes comply with the general theory of lubrication.

Predictive Estimation of Sliding Bearing Load-Carrying Capacity and Tribological Durability

A computational method is presented as a method for solving a plane contact problem of the theory of elasticity to determine the contact strength and tribological durability of sliding bearings. The effect of load and radial clearance on the initial contact pressures and their reduction due to wear is studied. The durability of the bearing is estimated. Qualitative and quantitative regularities of changes in contact parameters and durability from the factors under study are established. In particular, it has been shown that both contact angles and maximum contact pressures are approximately linearly dependent on the load, and the durability decreases nonlinearly with increasing load.

Analysis on Active Hydromagnetic Journal Bearing using Ansys

In this study Active hydromagnetic journal bearing is designed and analysed by using ANSYS tool. Active Hydromagnetic journal bearing is a combination of Hydrodynamic journal bearing & Active magnetic bearing. We know that hydrodynamic journal bearing used to low speed and high load carrying capacity & its drawback is at high-speed shaft surface is come in contact and there wear also happen. In this condition hydrodynamic bearing also damages from contaminants as dirt or ash, also in the rise in temperature. In the active magnetic bearing is used to high speed and low load carrying capacity. When increasing load carrying capacity of active hydromagnetic bearing, it also increases design of active hydromagnetic bearing. When combining Hydrodynamic journal bearing & Active magnetic bearing it reduces drawback of both bearing. It working on high speed and high load carrying capacity. When combining both bearing considering main parameter is clearance in hydrodynamic journal bearing & Air gap in active magnetic bearing.

Experimental Evidence on the Enhancement of Bearing Load Capacity by Localised Boundary Slip Effect

The lubrication performance of a bearing is determined by low friction and high load carrying capacity, which can be theoretically facilitated by partial-slip or heterogeneous-slip surface design. In the study, we numerically analysed a two-dimensional lubricated contact of a stationary slip slider surface and a moving non-slip plane by using the critical shear stress model. The proliferation of slip region on a slider surface with the relaxation in the critical shear stress criterion for boundary slip was examined. Insights were extracted from the results, and two partial-slip patterns, namely, lateral central stripe and inverse triangle, were proposed. These two new partial-slip patterns were validated numerically and experimentally through slider bearing tests, which demonstrate that the bearing load carrying capacity was enhanced beyond the predictions of the classical Reynolds equation.

Performance analysis of journal bearing operating on nanolubricants with TiO2, CuO and Al2O3 nanoparticles as lubricant additives

Present experimental study investigate the performance analysis of Journal bearing operating on Nanolubricants prepared by adding TiO2, CuO and Al2O3 nanoparticles as lubricant additives in Avalon ISO Viscosity grade 46 oil. By adding nanoparticles, the viscosity of the lubricant oil is improved, and, in effect, a performance characteristic of journal bearing is enhanced. Nanoparticles used for present work is mixed with base oil with volume fractions of 0.25%, 0.5%, 1% and 2% with the help of mechanical agitator and ultrasonication. Journal bearing Test Rig TR-60 is used to experimentally investigate pressure distribution and load carrying capacity. Performance of bearing is measured at speeds 250 rpm, 500 rpm and at loads 300 N and 450 N. The results indicate a rise in maximum pressure and load carrying capacity of journal bearing by adding TiO2, CuO, and Al2O3 nanoparticles as lubricant additives compared to base oil without nanoparticles additives.

Analytical Study of Non-Recessed Conical Hole Entry Hybrid/Hydrostatic Journal Bearing with Constant Flow Valve Restrictor

The present work studies the analysis of a non recessed hole entry conical hybrid/hydrostatic journal bearing adjusted for constant flow valve (CFV) restriction. The paper provides effectiveness between the conical bearings with hole entry operating in hybrid and hydrostatic mode. The Reynolds formulae, for the flow of fluid through the mating surfaces of a conical journal and bearing, are numerically worked out in both the modes considering the finite element analysis (FEA) and the necessary boundary preconditions. Holes in double row are marked on conical bearing circumference to accommodate the CFV restrictors, the angular distance between two holes are 30o apart from the apex. Qualitative features of the conical journal bearing system with hole entry have been elaborated to analyze bearing performance for radial load variation Wr = 0.25-2. Numerical results obtained from the present study indicate that load carrying capacity of conical bearing, operating in hydrostatic mode, is enhanced by the maximum pressure, direct fluid film damping and direct film stiffness coefficients vis-a-vis corresponding hybrid mode. 

Nanofluids for Performance Improvement of Heavy Machinery Journal Bearings: A Simulation Study.

Nanofluids have extensive applications in hydrodynamic journal bearings used in heavy industry machinery. Inorganic fullerene-like tungsten disulfide nanoparticles (IF-WS2 NPs) are the most common additive for lubrication purpose due to their excellent mechanical characteristics along with their effect on reducing friction and wear. In this work, a computational simulation approach with discrete phase modeling (DPM) of suspended nanoparticles was used to evaluate the application of the IF-WS2 nanofluid lubricant on load carrying capacity of high-load journal bearings where the normal loads are high, considering the bearing dimensions. For accurate simulation, nanofluid viscosity was calculated considering the aggregation effect of NPs by using scanning electron microscopy (SEM) imaging of the nanofluids. A benchmark study was first performed to assess the model accuracy. Hydrodynamic lubrication was simulated under different nanofluid weigh fractions. The simulated pressure distribution was then employed to determine the load capacity of the bearing. The results show an approximately 20% improvement of load carrying capacity at 5% weight fraction of WS2-oil nanofluid.

Effect of journal misalignment on the static characteristics of an innovative journal bearing with adjustable elements in load-on-pad and load-between-pad configurations

Purpose The purpose of this paper is to theoretically analyze an innovative form of variable bearing configuration having four pads with unique adjustability principle operated under journal misaligned conditions. The parameters such as load positions, degrees of misalignment (DM) and pad adjustment configurations influencing the steady-state performance of the four-pad adjustable bearing are detailed in this paper. Design/methodology/approach The proposed adjustable pad geometry possesses the ability to undergo radial and tilt motions in both inward and outward directions. Analysis is carried out by considering journal misalignment in vertical and horizontal planes with bearing modelled for load-on-pad and load-between-pad configurations. The film thickness equation derived to incorporate the radial and tilt adjustment parameters is further modified to accommodate the different load orientations and misaligned journal conditions. The pressure field equation is solved by applying finite-difference technique combined with Gauss Siedel iterative method. Findings At higher DM, peak pressures generated in the minimum film thickness region near the pad ends highly influences the bearing load carrying capacity. Results indicated that the adjustable four-pad bearing geometry is highly efficient in withstanding the journal misalignment by radially displacing and tilting the four pads in negative directions. Originality/value For bearing designers, this research highlights the importance of considering the misalignment factor during the design stages of an adjustable journal bearing. The proposed adjustability concept is proven to be effective enough to improve the bearing performance and, in turn, withstand the journal misalignment.

Non-linear stability analysis of two-layered porous journal bearings with velocity slip and percolation effect of additives of coupled-stress lubricant

In this paper a non-linear stability analysis of the two-layered porous journal bearing under coupled-stress lubricant has been presented with velocity slip phenomenon and additive’s percolation effect. In this non-linear transient analysis, system stability is determined by tracing the locus of the journal center and various trajectories of journal center locus have been represented in graphical form for different operating conditions. Furthermore, stability characteristics in respect of critical mass parameter and whirl ratio have been studied under various parametric conditions and a comparison between the linear and non-linear stability analysis have been demonstrated. To acquire the non-dimensional pressure values, non-dimensional transient Reynolds equation has been solved and with these pressure values, bearing load carrying capacity are derived. Fourth order Runge-Kutta method is used to solve the second order equations of motion for journal bearing system to obtain the stability characteristics. Results of this analysis may be helpful for designing such bearings.

Static and dynamic performance characteristics of powder lubricated symmetrical three-lobed bearing

Hydrodynamic oil bearings applied at elevated temperatures and extreme operating conditions are subjected to the problem of oil degradation. In order to overcome such conditions, dry powder lubricants are used as lubricants in the hydrodynamic journal bearings. Thus the problem of thermal degradation of oil at high temperatures can be eliminated. In this work, the static and dynamic characteristics of a symmetric three-lobed bearing lubricated with powdered particles have been predicted. Influence of the ellipticity ratio on the performance of the three-lobed bearing has also been investigated. It is observed that an increase in the ellipticity ratio increases the coefficient of friction and stability, but decreases the side leakage and the load carrying capacity of the three-lobed bearing. Also, it was observed that the large-sized powdered particles induce better load carrying capacity and better stability than the small-sized particles.

Investigation on effects of Fluid-Structure-Interaction (FSI) on the lubrication performances of water lubricated bearing in primary circuit loop system of nuclear power plant

The paper investigates the lubrication performances of water film under the consideration of different lubrication models in the primary circuit loop system of nuclear power plant. Variations between lubrication performances and rotating speeds, eccentricity ratios and lubrication models are obtained. Research results show that rotating speeds and lubrication models have significant influences on the lubrication performances. There exist optimum eccentricity ratios at which the bearing load carrying capacity and friction characteristics can strike the balance point. Research conclusions have guiding significances on the structure designs and optimization for such bearings in the primary circuit loop system.

Experimental comparison of the seizure loads of gray iron journal bearing and aluminum alloy journal bearing under aligned and misaligned conditions

Materials, surface roughness of bearing and shaft, and journal misalignment affect the seizure load of journal bearing. To improve the load carrying capacity of bearing and obtain better friction pair, this paper studies experimentally the seizure loads of a gray iron journal bearing and two kinds of aluminum alloy journal bearings under both aligned and misaligned conditions. Three shafts are used to study the effects of journal surface roughness and DLC coating. The journal center locus is recorded. Results show that the combination of DLC coating and the aluminum alloy with lower hardness has the largest seizure load and inclined angle, followed by the combinations of DLC coating and gray iron, and 40Cr steel and gray iron. The surface roughness values of bearing and shaft have a considerable negative effect on seizure load, especially for aligned condition.