The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Youbai Xie - One of the best experts on this subject based on the ideXlab platform.
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Investigations on the Relationship between Wear Debris Residence Time in Lubrication Systems and Online Oil Sampling Interval
Tribology Transactions, 2019Co-Authors: Bin Fan, Song Feng, Junhong Mao, Youbai XieAbstract:AbstractLubrication Systems have significant effects on the residence time of wear debris (RTWD), which limits the monitoring efficiency of the online debris sensor. The focus of this work is to investigate the relationship between RTWD in Lubrication Systems and online oil sampling interval. Firstly, a vector representation for the attenuation function of wear debris (AFWD) is introduced in order to depict the removal of wear debris with different sizes. Based on this, a mathematical model is developed to calculate the RTWD. A setting criterion for the online oil sampling interval is also proposed. Thereafter, RTWD in different size ranges was investigated experimentally, in which the concentration of wear debris larger than the micrometer rating of the filter decays to 10% of the initial concentration within 5 min. The results were consistent with the proposed model results. Moreover, we find that the online oil sampling interval must be determined by the residence time of large wear debris caused by ab...
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modeling and experimental investigations on the relationship between wear debris concentration and wear rate in Lubrication Systems
Tribology International, 2017Co-Authors: Bin Fan, Song Feng, Junhong Mao, Youbai XieAbstract:Abstract The aim of this work is to map the wear debris concentration with wear rate. A wear debris attenuation function is proposed to depict quantitatively the removal of wear debris. The total residual mass of wear debris in Lubrication Systems can be stated as the convolution of the wear rate and the wear debris attenuation function. Additionally, the dynamic responses of the wear debris concentration under different wear rate excitations are also presented. To simulate and verify how the debris concentration changes, an oil Lubrication system test rig is built, and on-line visual ferrograph (OLVF) is used to monitor the debris concentration. Two experimental results indicate that the variation of the wear debris concentration is consistent with the model result.
Douglas Hargreaves - One of the best experts on this subject based on the ideXlab platform.
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an isoviscous isothermal model investigating the influence of hydrostatic recesses on a spring supported tilting pad thrust bearing
Tribology International, 2012Co-Authors: Dennis V De Pellegrin, Douglas HargreavesAbstract:Abstract Tilting-pad hydrodynamic thrust bearings are used in hydroelectric power stations around the world, reliably supporting turbines weighing hundreds of tonnes, over decades of service. Newer designs incorporate hydrostatic recesses machined into the sector-shaped pads.With the aid of external oil pressurisation at low rotational speeds, oil film thickness is increased, thereby reducing friction and wear to the benefit of service life and reliability. It follows that older generating plants, lacking such assistance, stand to benefit from being retrofitted with hydrostatic Lubrication Systems. The design process is not trivial however – the need to increase the groove area to permit spontaneous lifting of the turbine under hydrostatic operation conflicts with the need to preserve performance of the original plane pad design. A haphazardly designed recess can change the pressure distribution of the oil film in such a way as to tilt the pad away from its optimum position. This may lead to reduced oil film thickness and increased temperature, which is concomitant with reduced mechanical efficiency and increased risk of damage to the bearing surfaces. It is therefore, inadvisable to ignore the presence of grooves in simulations. In this work, a numerical study of a sector-shaped pad is undertaken to understand how recess size and shape can affect the performance of a typical bearing. An isoviscous, isothermal model has been used in this instance because the operating conditions of the turbine in question were shown not to be severe enough to warrant the computational expense of a fully coupled thermoelastic hydrodynamic model.
Lincoln Cardoso Brandão - One of the best experts on this subject based on the ideXlab platform.
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Comparison among different vegetable fluids used in minimum quantity Lubrication Systems in the tapping process of cast aluminum alloy
Journal of Cleaner Production, 2016Co-Authors: Sergio Luiz Moni Ribeiro Filho, Jessica Vieira, Juliano Oliveira, Étory Madrilles Arruda, Lincoln Cardoso BrandãoAbstract:Abstract Nowadays, cooling fluids are the great environmental issue, because they consume a considerable amount of water and can pollute natural water sources for decades when they are discarded and disposed of irregularly. Based on this, the Minimum Quantity Lubrication technique, that uses low amounts of fluids, has been used in drilling processes since 1990 and is a major breakthrough in reducing the use of cutting fluids. In this study, three different Minimum Quantity Lubrication cutting fluids were tested and compared with emulsions in cut and form tapping processes. A Full factorial design was performed to identify the significant effect of the type of oil, cooling/Lubrication system and cutting/forming speed on the torque value of the tapping processes. A steering system carcass manufactured by A306 cast aluminum alloy was used as a workpiece in the tapping operations. The results showed that fluid A (ECOCUT) in the Minimum Quantity Lubrication system has a high potential to reduce torque value while minimizing the friction and can avoid that tools break, in some situations. Furthermore, form tapping was found to be a suitable alternative, since it does not generate chips, which reduces costs with recycling, storage, and waste disposal.
Dennis V De Pellegrin - One of the best experts on this subject based on the ideXlab platform.
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an isoviscous isothermal model investigating the influence of hydrostatic recesses on a spring supported tilting pad thrust bearing
Tribology International, 2012Co-Authors: Dennis V De Pellegrin, Douglas HargreavesAbstract:Abstract Tilting-pad hydrodynamic thrust bearings are used in hydroelectric power stations around the world, reliably supporting turbines weighing hundreds of tonnes, over decades of service. Newer designs incorporate hydrostatic recesses machined into the sector-shaped pads.With the aid of external oil pressurisation at low rotational speeds, oil film thickness is increased, thereby reducing friction and wear to the benefit of service life and reliability. It follows that older generating plants, lacking such assistance, stand to benefit from being retrofitted with hydrostatic Lubrication Systems. The design process is not trivial however – the need to increase the groove area to permit spontaneous lifting of the turbine under hydrostatic operation conflicts with the need to preserve performance of the original plane pad design. A haphazardly designed recess can change the pressure distribution of the oil film in such a way as to tilt the pad away from its optimum position. This may lead to reduced oil film thickness and increased temperature, which is concomitant with reduced mechanical efficiency and increased risk of damage to the bearing surfaces. It is therefore, inadvisable to ignore the presence of grooves in simulations. In this work, a numerical study of a sector-shaped pad is undertaken to understand how recess size and shape can affect the performance of a typical bearing. An isoviscous, isothermal model has been used in this instance because the operating conditions of the turbine in question were shown not to be severe enough to warrant the computational expense of a fully coupled thermoelastic hydrodynamic model.
Yasuhiro Sodani - One of the best experts on this subject based on the ideXlab platform.
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high speed rolling by hybrid Lubrication system in tandem cold rolling mills
Journal of Materials Processing Technology, 2015Co-Authors: Yukio Kimura, Noriki Fujita, Yukihiro Matsubara, Yosuke Amanuma, Osami Yoshioka, Koji Kobayashi, Yasuhiro SodaniAbstract:Abstract Lubrication is one of the most important factors for improving the productivity of tandem cold rolling mills, as it is possible to increase the rolling speed of thin gauge steel strips and prevent chatter when rolling materials with high deformation resistance. In this study, a new hybrid Lubrication system is proposed and its effectiveness is clarified. The system is based on a lubricant recirculation system combined with a system for flexible Lubrication control. The key to realizing the new lubricant system is control of plate-out oil film formation on the strip surface under high-speed rolling conditions. The plate-out oil film formation of emulsions is investigated, and the conditions for achieving a sufficient plate-out oil film are clarified. The time-dependent property, oil droplet size, and emulsion concentration are found to have significant effects on plate-out behavior. In addition, the conditions for practical application of hybrid Lubrication Systems are discussed from the viewpoint of realizing effective plate-out control. A new hybrid Lubrication system was investigated, and it successfully enabled flexible controllability of Lubrication conditions and achieved the high-speed stable rolling, while maintaining an oil consumption rate equal to that of recirculation Systems.
