Experimental Study on an Influence of Bearing Geometry and TiO2 Nanoparticle Additives on the Performance Characteristics of Fluid Film Lubricated Journal Bearing (original) (raw)
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Arabian Journal for Science and Engineering, 2022
Abstract This study is concerned with steady-state thermo-hydrodynamic performance analysis of journal bearing lubricated with experimentally characterized titanium dioxide and zinc oxide nano-lubricants using the computational fluid dynamics technique. For this purpose, nano-lubricants have been prepared by blending different weight fractions of the nanoparticles in SAE15W40 base oil. The prepared nano-lubricants are characterized by performing different experimental tests such as the X-ray diffraction, dynamic light scattering and the scanning electron microscopy. The nano-lubricants viscosities are measured by using suitable rheometer and then compared with that calculated by Krieger–Dougherty equation. The effect of aggregated nanoparticles in the prepared nano-lubricants on the nano-lubricants viscosities has been considered by evaluating the aggregate ratio which was found to be 2.4 and 2.1 for titanium dioxide and zinc oxide nano-lubricants, respectively. A three-dimensional computational fluid dynamic model has been built to analyze the thermal performance of the journal bearing using ANSYS FLUENT software. The effects of the particle weight fraction, the journal speed, bearing eccentricity ratio, and the cavitation on the thermo-hydrodynamic behavior of such bearing have been extensively studied. The obtained results show that dispersing small weight fractions of the nanoparticles in the base oil increases the load-carrying capacity by about 9–23% with a negligible increase in oil film temperature.
Tribology in Industry, 2018
This paper presents the performance analysis for plain and elliptical journal bearing operating with industrial lubricants. Titanium dioxide nanoparticle of size 40 nm is used as a lubricant additive to examine the performance of the bearing. Comparative analysis is carried out for three different lubricants with titanium dioxide (0.5% wt) nanoparticles. Performance of bearing is measured at speeds ranging from 500 r.p.m. to 1000 r.p.m. and at 1000 N load. The study of antiwear and antifriction properties for lubricants is carried out on four ball Tribo-tester for operating conditions specified by ASTM standards. An influence of titanium dioxide as an additive on the performance characteristics of the journal bearing such as pressure distribution, load carrying capacity, attitude angle, power loss, oil flow rate, side leakage, frictional force and temperature rise in a film is examined in this paper. The elliptical journal bearing improves the performance of a system over plain bearing operating with the same lubricant.
The aim of this project is experimental analysis of Hydrodynamic journal bearing with Nano particle added lubricating oil. The dynamic analysis of hydrodynamic solid journal bearing operating under nano lubricants will be presented in this paper. The load carrying capacity of solid journal bearing mainly depends upon the viscosity of the Lubricant being used. The addition of nano particles on commercial lubricants may enhance the viscosity of lubricant and in turn changes the performance characteristics. In the proposed work is about to obtain pressure distribution in the clearance space of the solid journal bearing.
Al-Nahrain Journal for Engineering Sciences, 2017
In the present work the worn journal bearing is simulated to discuss the effect of adding TiO2 nanoparticles to the base oil on its thermal performance. An extensive numerical investigation is carried out to study the effect of different parameters affecting thermal performance of worn journal bearing such as the eccentricity ratio (e), the wear depth parameter (δ), and the nanoparticle concentration (Φ). The computational approach is provided by using finite difference method for solving the governing equations, namely, the modified Reynolds equation, energy and heat conduction equations with suitable equation to include the variation of the oil film thickness due to the bearing wear in order to estimate the benefits of using nanolubricant in worn journal bearings. Oil viscosity dependence on nanoparticle concentrations is considered by using Krieger Dougherty model. The mathematical model as well as the computer program prepared to solve the governing equations were validated by c...
Diagnostyka, 2022
The main objective of the present work is to study the behavior of Nano-lubricated journal bearing considering elasticity and variable viscosity effects. A mathematical model for a journal bearing is employed using three-dimensional computational fluid dynamics. The study is implemented for a journal bearing with laminar flow and smooth surfaces lubricated with pure oil as well as lubricants containing different concentrations of Al2O3 Nano-particles. The dependence of the oil viscosity on the temperature is considered by using the modified Krieger Dougherty model. Pressure, temperature and elastic deformation in addition to the bearing load-carrying capacity of the bearing working under different eccentricity ratios (0.1-0.6) have been studied. The mathematical model is confirmed by comparing the results of the pressure and temperature distributions obtained in the current work with those obtained by Ferron et al.(1983) for a bearing lubricated with pure oil. Also, the pressure obtained for the Nano-lubricated bearing of the present work is validated with that obtained by Solighar (2015). The results are found in good agreement with a maximum deviation not exceeding 5%. The obtained results show that the oil film pressure increases by about 17.9% with a slight decrease in oil film temperature and friction coefficient.
The main objective of the present work is to study the behavior of Nano-lubricated journal bearing considering elasticity and variable viscosity effects. A mathematical model for a journal bearing is employed using three-dimensional computational fluid dynamics. The study is implemented for a journal bearing with laminar flow and smooth surfaces lubricated with pure oil as well as lubricants containing different concentrations of Al2O3 Nano-particles. The dependence of the oil viscosity on the temperature is considered by using the modified Krieger Dougherty model. Pressure, temperature and elastic deformation in addition to the bearing load-carrying capacity of the bearing working under different eccentricity ratios (0.1-0.6) have been studied. The mathematical model is confirmed by comparing the results of the pressure and temperature distributions obtained in the current work with those obtained by Ferron et al.(1983) for a bearing lubricated with pure oil. Also, the pressure obtained for the Nano-lubricated bearing of the present work is validated with that obtained by Solighar (2015). The results are found in good agreement with a maximum deviation not exceeding 5%. The obtained results show that the oil film pressure increases by about 17.9% with a slight decrease in oil film temperature and friction coefficient.
BEHAVIOR OF NANO LUBRICANT OPERATED HYDRODYNAMIC SOLID JOURNAL BEARING
technicaljournalsonline.com
The dynamic analysis of hydrodynamic solid journal bearing operating under nano lubricants is presented in this paper. The load carrying capacity of solid journal bearing mainly depends upon the viscosity of the Lubricant being used. The addition of nano particles on commercial lubricants may enhance the viscosity of lubricant and in turn changes the performance characteristics. In the proposed work, to obtain pressure distribution in the clearance space of the solid journal bearing, modified Reynolds equation is used. The film extent of the bearing is established by iterative procedure dynamic characteristics in terms of stiffness coefficients, threshold speed, damping coefficients are evaluated for different eccentricity ratios.
International Journal of Engineering and Advanced Technology, 2019
This article presents the static performance characteristics of a plain journal bearing with non-Newtonian lubricant (power law) at different aspect ratio. Finite difference approach is employed to solve the modified Reynold equation. Hydrodynamic regime is assumed to be isothermal. The fluid film pressure is established using modified Reynold equation and Reynold boundary condition through iteratively. Thus the obtain pressure is used to find-out the performance characteristics for instance load carrying capacity, attitude angle, friction force and side leakage. Three aspect ratios are assumed 0.5, 1 and 1.5 for the present study. The effect of different aspect ratios on performance characteristics at different power law index (0.9, 1 and 1.1) has been presented.
Properties and Performance of Gas-Expanded Lubricants in Tilting Pad Journal Bearings
Tribology Transactions, 2013
Lubricants enable proper function and reduce friction in rotating machinery, but they can also contribute to power loss and heat buildup. Gas-expanded lubricants (GELs) have been proposed as tunable mixtures of lubricant and CO 2 under pressure with properties such as viscosity that can be controlled directly in response to changing environmental or rotordynamic conditions. In this work, experimental results of GEL viscosity, gas diffusivity, and thermal conductivity were combined with high-pressure phase equilibrium data to understand how these mixtures will behave in tilting pad journal bearings under a range of industry-relevant high-speed conditions. Simulations were carried out using the experimental data as inputs to a thermoelastohydrodynamic model of tilting pad journal bearing performance. Viscosity could be easily tuned by controlling the composition of the GEL and the effect on bearing efficiency was appreciable, with 14-46% improvements in power loss. This trend held for a range of lubricant chemistries with polyalkylene glycols, polyalpha olefins, and a polyol ester tested in this work. Diffusivity, which drives how readily CO 2 and lubricants form homogenous mixtures, was found to be a function of the viscosity of the synthetic lubricant, with more viscous lubricants having a lower diffusivity than less viscous formulations. Model results for a bearing in a pressurized housing suggested that cavitation would be minimal for a range of speed conditions. Other bearing parameters, such as eccentricity, temperature, and minimum film thickness were relatively unchanged between conventionally lubricated and GEL-lubricated bearings, suggesting that the efficiency improvements could be achieved with few performance tradeoffs.
Study of hydrodynamic behaviour of large bearings depending on the viscosity of the lubricant
MATEC Web of Conferences, 2017
The research refers to study of hydrodynamic behavior of large bearings equipped with automatic lubrication system, where the liquid used may have a viscosity with variable values depending on the temperature or depending on the additive used. The introduction of additives with nanoparticles causes modification of viscosity and a significant reduction of friction coefficient. This study establishes a direct link between the friction, viscosity and tensions that occur in the contact area. Experimental studies confirm improving tribological properties of the contact area between the bearing rollers and raceways, through attracting nanoparticles on surfaces in contact and reducing friction coefficient. Accomplished finite element analysis showed decrease of the contact stresses, therefore decrease of the wear and increase the life of the bearing. Research has concluded that influencing viscosity and friction coefficient of lubricant can result in reducing wear of the bearing components, as well as increase the lifetime of bearing.