non-Newtonian Lubricant Research Articles

Effect of micro-particles on rough surface spur gears under TEHL with non-Newtonian lubricant

Effect of micro-particles on rough surface spur gears under TEHL with non-Newtonian lubricant

Performance of 180° partial hole-entry hybrid journal bearing considering the combined influence of surface roughness and non-Newtonian behaviour of lubricant

The present paper is aimed to analyse the static and dynamic performance of a capillary compensated 180° partial non-recessed (hole-entry) hybrid journal bearing system considering the combined influence of surface roughness and nonlinear behaviour of the lubricant. The relation between shear stress and shear strain rate of non-Newtonian lubricant has been modelled by using the power law model. To analyse, the performance of hybrid journal bearing, the governing Reynolds equation has been solved by using the finite element method. The numerically simulated result indicates the effect of surface orientation parameters (γ), power law index (n) and surface roughness parameter (Λ) on the performance characteristics. The present results indicate that, the transverse roughness pattern (γ = 1 / 6) gives better stability of bearing as compared to other roughness patterns. Therefore, a proper selection of roughness parameters (γ and Λ) and power law index (n) is essential to obtain optimum performance of bearing.

Influence of textured surface on the performance of non-recessed hybrid journal bearing operating with non-Newtonian lubricant

In the present work, a comparative study between textured surface and non-textured surface non-recessed hybrid journal bearing configurations is presented. To obtain the performance characteristics parameters of non-recessed hybrid journal bearing, the Reynolds equation, which governs the flow of lubricant in the clearance space, is solved using FEM and the performance parameters are computed. The shear stress–strain relation of lubricant is modeled with the help of a power-law fluid model. The numerically simulated results show that the textured non-recessed hybrid journal bearing provides improved stability parameter than that of journal bearing with non-texturing.

A comparative study of full and partial textured hybrid orifice compensated circular thrust pad bearing system

This work concern with the performance of hybrid circular thrust pad bearing having partial and full textured surface, operating with power law lubricant has been studied. The governing Reynolds equation is non-linear with pressure. Finite element method with JFO boundary conditions has been implemented to obtain fluid film pressure on the bearing surface and cavitation zone. The numerically simulated results reveal that, among the different non-Newtonian lubricants, the dilatant one provides the minimum value of frictional power loss. Results show that surface texture and the behavior of lubricant significantly changes the frictional power loss and other performance parameters. It is expected that the result obtained will be very much quite useful for bearing designer and academic community.

Investigation of Friction Using Non-Newtonian Lubricant Model in Hydrostatic Extrusion of Tungsten Alloy

Friction at die/billet interface is a complex phenomenon affected by various operating and process parameters in metal forming industries. In presence of lubricating layer at the interfacial contact friction effect is reduced and enhances tool life and surface quality of product. The lubricant viscosity is strongly dependent on pressure and temperature during deformation of hard material and an accurate prediction of lubricants viscosity leads to realistic results in the work zone. Therefore, the paper incorporates numerical simulation of friction at the die/billet interface in hydrostatic extrusion of tungsten alloy 93W for three different lubricants whose rheology is represented by a Non-Newtonian friction model. The billet heating effect is incorporated in the investigation and results show that the co-efficient of friction varies in a range (0.058 to 0.062) along the work zone for various lubricating conditions in hydrostatic extrusion process.

A novel Reynolds equation of non-Newtonian fluid for lubrication simulation

The non-Newtonian phenomenon is significant in hydrodynamic lubrication of some special lubricants, or elastohydrodynamic lubrication (EHL). However, the conventional methods to solve the non-Newtonian lubrication problem are either too complicated or inaccurate. This paper puts forward a Reynolds equation for general lubrication problem of the non-Newtonian fluid by treating the lubricant flow as the superposition of the Poiseuille flow and Couette flow. Then, as examples, a set of simulations for EHL in the line contact are presented to investigate the feasibility of the method. Finally, comparisons with the conventional methods establish the validity and simplicity of the method.

Tribological behavior of femtosecond laser textured surfaces of 20CrNiMo/beryllium bronze tribo-pairs

Purpose – This paper aims to carry out tribological experiments to explore the applications of femtosecond laser surface texturing technology on rock bit sliding bearing to enhance the lifetime and working performance of rock bit sliding bearing under high temperature and heavy load conditions. Design/methodology/approach – Surface textures on beryllium bronze specimen were fabricated by femtosecond laser ablation (800 nm wavelength, 40 fs pulse duration, 1 kHz pulse repetition frequency), and then the tribological behaviors of pin-on-disc configuration of rock bit bearing were performed with 20CrNiMo/beryllium bronze tribo-pairs under non-Newtonian lubrication of rock bit grease. Findings – The results showed that the surface texture on beryllium bronze specimens with specific geometrical features can be achieved by optimizing femtosecond laser processing via adjusting laser peak power and exposure time; more than 52 per cent of friction reduction was obtained from surface texture with a depth-to-diameter ratio of 0.165 and area ratio of 5 per cent at a shear rate of 1301 s−1 under the heavy load of 20 MPa and high temperature of 120°C, and the lubrication regime of rock bit bearing unit tribo-pairs was improved from boundary to mixed lubrication, which indicated that femtosecond laser ablation technique showed great potential in promoting service life and working performance of rock bit bearing. Originality/value – Femtosecond laser-irradiated surface texture has the potential possibility for application in rock bit sliding bearing to improve the lubrication performance. Because proper micro dimples showed good lubrication and wear resistance performance for unit tribo-pairs of rock bit sliding bearing under high temperature, heavy load and non-Newtonian lubrication conditions, which is very important to improve the efficiency of breaking rock and accelerate the development of deep-water oil and gas resources.

A study of 2-lobe symmetric hole entry hybrid journal bearing operating with non-Newtonian lubricant considering thermal effects

This paper presents the thermohydrostatic solution of 2-lobe symmetric hole entry hybrid journal bearing compensated with orifice restrictor and operating with cubic law lubricant. Simultaneous solutions of Reynold׳s, energy and conduction equations have been obtained by using finite element method and a suitable iterative scheme. The performance characteristics parameters of 2-lobe symmetric bearing system have been presented for various bearing geometries and nonlinearity factors. The numerically simulated results of the study indicates that the variation of viscosity of cubic law lubricant due to temperature rise and bearing geometry changes the bearing performance quite significantly.

Non-Newtonian Inertia Squeeze Film Characteristics in Rectangular Stepped Plates

A study of non-Newtonian inertia squeeze film in rectangular stepped plates has been presented in this paper. Applying the momentum integral method incorporating the micro-continuum theory of non-Newtonian fluids, a non-Newtonian inertia lubrication equation is derived. It is found that the fluid inertia effects yield in a higher normal load capacity as well as a longer squeeze film time as compared to the non-Newtonian stepped squeeze film in the absence of fluid inertia forces.

Taking into account the universal dependence of the viscosity of a boundary lubricant on temperature and strain rate to describe stop-start experiments

The tribological system consisting of two blocks with atomically smooth surfaces separated by a boundary lubricant layer is considered. A spring the free end of which is driven is attached to one of the blocks. A thermodynamic model is used to study the influence of the universal relationship between the viscosity of a non-Newtonian lubricant and temperature and strain rate on friction modes. The melting and solidification of the lubricant layer are taken to be second-order phase transformations. The specific features of widely used stop-start experiments, where a system stops for a certain time and then resumes its motion, are analyzed. The influence of the temperature, the shear velocity, and the external load on the behavior of the system is investigated. The conditions of transitions between the fluid (sliding), stick-slip, and dry friction modes are determined for the lubricants consisting of linear alkanes of various lengths.

A Layered-Rheology Model for Thin Film Elastohydrodynamic Lubrication of Circular Contacts

The modified Reynolds equation for power-law fluid is derived from the viscous adsorption theory for thin film elastohydrodynamic lubrication (TFEHL) of circular contacts. The lubricating film between solid surfaces is modeled as three fixed layers, which are two adsorption layers on each surface and a middle layer. The differences between classical EHL and TFEHL with non-Newtonian lubricants are discussed. Results show that the TFEHL power law model can reasonably calculate the pressure distribution, the film thickness, and the velocity distribution. The thickness and viscosity of the adsorption layer and the flow index influence significantly the lubrication characteristics of the contact conjunction.

Characterization of lubrication of asymmetric rollers including thermal effects

Purpose– The purpose of this paper is to deal with the qualitative analysis of hydrodynamic lubrication of asymmetric rollers with non-Newtonian incompressible power law lubricants including Newtonian.Design/methodology/approach– The fluid flow governing equations such as equation of motion along with continuity and thermal equations are solved first analytically and investigated numerically by the Runge-Kutta Fehlberg method.Findings– As a result of this work, it is found that there is a significant change in temperature, pressure, load and traction with Newtonian and non-Newtonian fluids.Research limitations/implications– The authors considered incompressible hydrodynamic lubrication of two rigid asymmetric rollers, one of them is assumed to be adiabatic. The convection term of the heat flow equation is taken in its average form.Originality/value– It is a theoretical problem of two heavily loaded rigid cylindrical rollers with cavitations, where the consistency of the power law lubricant is assumed to vary with pressure and the mean film temperature. It has not appeared in the literature.

Thermal Analysis on Thrust Pad Bearing with Non-Newtonian Lubricant

Hydrodynamic pad thrust bearings are widely used, due to their low friction, good load carrying capacity and high damping characteristics, in high speed rotating machines, such as pumps, compressors, turbines, turbo generators. However, the need for high load bearing capabilities and compactness of the thrust pad bearings has attracted the attention of engineers. The design of such thrust pad bearings involves selection of bearing materials, lubricants and operating conditions. As the performance of lubricants plays a vital role in the life cycle of bearings, thus the present work examines the thermophysical properties of non-Newtonian surrogate lubricants. The lubricant properties at different temperatures were extracted from NIST- Supertrapp ® and a correlation is developed which is further used in the computational analysis of thrust pad bearing. A steady state thermal analysis is done on the thrust pad bearings which are modeled and meshed in ANSYS ® 14.5. It was observed that the temperature variation on the outer surface to be varying linearly whereas a non-linear variation has been identified at inner surface of a pad in a thrust pad bearing initiating thermal stresses. Moreover, these thermal stresses may contribute finally to the reduction in performance with respect to wearing of pads. The present work also focuses on temperature dependent thermophysical properties on the temperature distribution of thrust pad bearings.

Rough Soft-EHL with Non-Newtonian Lubricant

This paper presents the effect of surface roughness on soft elastohydrodynamic lubrication in circular contact with non-Newtonian lubricant. The time independent modified Reynolds equation, elastic equation and lubricant viscosity equation were formulated for compressible fluid. Perturbation method, Newton-Raphson method, finite different method and full adaptive multigrid method were implemented to obtain the film pressure, film thickness profiles and friction coefficient in the contact region at various the amplitude of surface roughness, surface speed of sphere, modulus of elasticity and radius of sphere. The simulation results showed that the film thickness in contact region depended on the profile of surface roughness. The minimum film thickness decreased but maximum film pressure and friction coefficient increase when the amplitude of surface roughness and modulus of elasticity increased. For increasing surface speeds, the minimum film thickness and friction coefficient increase but maximum film pressure decreases. When radius of sphere increases, the minimum film thickness increases but maximum film pressure and friction coefficient decrease.

Effect of Nano and Micro Particle Additives on Rough Surface TEHL with Non-Newtonian Lubricant

<img style="border-width: 0px; margin: 0px; padding: 0px; left: 0px; top: 0px; width: 60px; height: 25px; visibility: hidden; position: absolute; z-index: 2147483647; cursor: pointer;" id="bing-msbbp-copy-img" src="data:image/png;base64,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" /><a style="border-width: 0px; margin: 0px; padding: 0px; left: 0px; top: 0px; width: 60px; height: 25px; visibility: hidden; position: absolute; z-index: 2147483647; cursor: pointer;" id="bing-msbbp-search-anchor" target="_blank"></a><img style="border-width: 0px; margin: 0px; padding: 0px; left: 0px; top: 0px; width: 60px; height: 25px; visibility: hidden; position: absolute; z-index: 2147483647; cursor: pointer;" id="bing-msbbp-search-img" src="data:image/png;base64,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" />This paper presents the results of a analysis of rough thermo-elastohydrodynamic lubrication (TEHL) of line contact with non-Newtonian lubricant blended with Al2O3nanoparticles and MoS2 microparticles. The simultaneous systems of time independent modified Reynolds equation, elasticity equation, load carrying with micro particle equation and energy equation were solved numerically using multigrid multilevel with full approximation technique. In this study, the effect of Al2O3nanoparticle and MoS2microparticle additives and surface roughness were implemented to obtain film thickness, film pressure, film temperature, friction coefficient and load carrying with microparticle in the contact region. The simulation results showed that the maximum film temperature and friction coefficient increase slightly but the minimum film thickness decreases slightly with an increase in Al2O3nanoparticle concentration due to thermal enhancement of nanofluid. For increasing of microparticle concentration, the minimum film thickness and friction coefficient decrease because the increasing of friction heating of MoS2microparticle.

Theoretical Investigation in an Artificial Hip Joint under Elastohydrodynamic Lubrication

This paper describes the transient analysis of artificial hip joint during human movement under elastohydrodynamic lubrication (EHL) with non-Newtonian lubricants based on a Carreau model. During walking, the load and velocity are varying with time. The numerical schemes employed perturbation method, Newton-Raphson method and multi-grid multilevel with full approximation technique to solve the time-dependent modified Reynolds equation and elasticity equation with initial conditions. The aim of this study was investigated the characteristics of elastohydrodynamic lubrication, profile of film pressure and film thickness profile in human artificial hip joint during human movement. Numerical results show the transient film thicknessincreased and then decreased because of reverse motion. In smooth surface condition, film thickness for Newtonian fluids is slightly higher than the film thickness for non-Newtonian fluid. The amplitude of surface roughness has significant effect on the film thickness,the minimum film thickness decreased when the amplitude of surface roughness increases.

Static Analysis of Finite Hydrodynamic Journal Bearing in Turbulent Regime with Non-Newtonian Lubricant

Static Analysis of Finite Hydrodynamic Journal Bearing in Turbulent Regime with Non-Newtonian Lubricant

DIFFERENTIAL AND RECURRENCE UNIFIED REYNOLDS EQUATIONS AND MEGA ALGORITHM FOR THEIR NUMERICAL SOLUTIONS

The objective of the research under the paper topic is an analytical, unified formulation of a new standardized view of general solution of hydrodynamic problem using algorithm to determine changes of the components of the velocity vector, the distributions of hydrodynamic pressure, load carrying capacity, of slide bearings with cooperating curvilinear, orthogonal surfaces that are lubricated with a various non-Newtonian lubricants. In this paper for nonNewtonian lubricants are questioning the hitherto prevailing assumptions using in hydrodynamic theory of lubrication such as constant value of lubricant viscosity and pressure in the thickness of lubricating gap i.e. in gap height direction. Finally, the non-homogeneous partial differential equation generated with variable coefficients that is the result of the various boundary conditions being imposed that are different for each problem solved is an equation that determines the distributions of hydrodynamic pressure values. This equation is to be written in the form of a unified non-homogenous partial recurrence equation with variable coefficients. The Authors foresee that a mega-algorithm will be developed for the solution of this equation in a numerical form. This equation in particular cases is an equivalent of modified Reynolds equations in the research that has been conducted so far concerning the hydrodynamic theory of lubrication.

Effect of Solid Particle on Rough Thermo-Elastohydrodynamic Lubrication with Non-Newtonian Lubricant

This paper presents the performance characteristics of rough thermo-elastohydrodynamic lubrication (TEHL) with non-Newtonian liquid–solid lubricant based on a Power law viscosity model. The time independent modified Reynolds equation, elasticity equation and energy equation were solved numerically using finite different method, Newton-Raphson method and multigrid multilevel methods were used to obtain the film pressure profiles and film thickness in the contact region. The effects of amplitude of surface roughness and concentration of solid particles are examined. The simulation results showed surface roughness has rapidly effect on film pressure and film temperature. The effect of solid particle can be increases film thickness and decreases friction coefficient.

Impact of high pressure and shear thinning on journal bearing friction

For the study of mixed lubrication in journal bearings, this paper employs a combined experimental and simulative approach. Extensive measurements on a journal bearing test rig with a low viscosity 0W20 multi-grade lubricant provide a solid basis which is complemented by experimental lubricant data that is measured under high pressure and high shear rates. In this paper, this data is used to investigate the impact of the piezoviscous effect and the non-Newtonian lubricant properties on the friction power losses in journal bearings over a wide range of dynamic loads and shaft speeds.In particular, this work seeks to predict the friction power losses for journal bearings under both moderate (50MPa peak load) and high dynamic loads (100MPa peak load) using the recently presented accurate numerical method (Allmaier et al., 2011 [1], Allmaier et al., 2013 [2]). From the direct comparison to the experimental data a key finding is that the simulation conforms very closely to the measured data. To be more exact, the agreement lies within the measurement uncertainty.Following this result, the influence of the often neglected piezoviscous effect and the non-Newtonian lubricant rheology is investigated. We conclude that both the piezoviscous effect and the non-Newtonian behaviour are essential to describe the lubrication with multi-grade lubricants in journal bearings. Only the consideration of both properties describes the experimental data very accurately over the entire range of operating conditions studied.