Industrial Lubrication and Tribology

Zhou, Zeyuan; Jia, Hekun; Yin, Bifeng

doi: 10.1108/ilt-08-2021-0340pmid: N/A

This paper aims to present a 3D static performance analysis model for the gas foil journal bearing to provide better understanding of the gas foil journal bearing and extend the development of the calculation about the static performance.Design/methodology/approachThe foil bearing can be seen as a shell structure, and the mixed interpolation of tensorial components (MITC) element was used to build the shell model. The augmented Lagrange method was used to calculate the contact involving friction between foils and between the foil and the bearing sleeve. A displacement-controlled load scheme was used to calculate the deformation of the foils. A mapping operator was used to map the film pressure from the gas to the surface of the top foil.FindingsThis method provides high precision of calculation in the prediction of the static performance. The calculation results were compared with the experimental data, and they show good agreement. Meanwhile, the model can be applied in the prediction of the bearing performance in a broad range of working conditions.Originality/valueThis method extends the calculation of the gas foil journal bearing to a 3D scale and shows good agreement with the experimental data. Meanwhile, the present model has a good adaptability on the revolution speed and can be applied to the predictions in varied working conditions.

Song, Jingfu; Zhao, Gai; Ding, Qingjun; Yang, Ying

doi: 10.1108/ilt-12-2021-0470pmid: N/A

The purpose of this paper is to investigate the effect of SiO2 on the tribological properties of polytetrafluoroethylene (PTFE) composites from an atomic level.Design/methodology/approachEffect of SiO2 on the tribological properties of PTFE sliding against Cu was studied by molecular dynamics (MD) simulations to explore the inherent mechanisms from an atomic level.FindingsSiO2 had a higher interaction energy with PTFE than copper, which contributed to an increase of interfacial temperature and velocity with severe adhesive wear on the PTFE molecules.Originality/valueThis study reveals the mechanism of SiO2 on the friction and wear behavior of PTFE by MD simulation.

Zhang, Cong; Jiang, Jinbo; Peng, Xudong

doi: 10.1108/ilt-03-2022-0066pmid: N/A

This paper aims to acquire the phase distribution and sealing performance of supercritical carbon dioxide (SCO2) dry gas seals with phase transitions.Design/methodology/approachThe SCO2 spiral groove dry gas seal is taken as the research object. The finite differential method is applied to solve the governing equations. Furthermore, the phase distribution and the sealing performance are obtained. Compared to the ideal gas model, the effect of phase transitions on sealing performance is also explored.FindingsVaporization is likely to occur near the inner radius when SCO2 dry gas seals are operated near the critical point. Whether phase transitions are considered in the model affects the sealing performance seriously. When phase transitions are considered, the sealing performance depends significantly on the working conditions, and unexpected results are produced when inlet conditions approach the critical point.Originality/valueThe numerical model for SCO2 dry gas seals with phase transitions is established. The phase distribution and the sealing performance of SCO2 dry gas seals are explored.

Syed, Nayab Rasool; Kakoty, Sashindra Kumar

doi: 10.1108/ilt-04-2022-0115pmid: N/A

The purpose of this paper is to compare the spherical protruded and dimple textured journal bearings performance characteristics with the untextured bearing.Design/methodology/approachThe governing Reynolds equation considering the mass conserving (JFO) boundary conditions is solved using the computationally efficient progressive mesh densification (PMD) method. The central difference scheme is used for the discretization of the governing Reynolds equation. The numerical code developed is validated with the experimental results available in the literature.FindingsFrom this numerical study, it has been observed that the protruded textured journal bearing gives better performance compared to the dimple textured and untextured journal bearing for friction variable, whereas dimple textured journal bearing provides better performance compared to the protruded textured and untextured journal bearing for load carrying capacity and flow coefficient. For better performance, dimple and protruded textured bearings must be textured in second-half textured region configuration.Practical implicationsThe results shown here would be quite useful for the researchers generally and the bearing designers particularly.Originality/valueThe load carrying capacity should be maximum whereas, the friction coefficient should be minimum and also the adequate flow of lubricant is necessary to maintain hydrodynamic lubrication and to remove the heat generated within the bearing due to friction, which impacts the bearing performance and life. Thus, this study would be significant in effective bearing design aspect.

Chen, Cuicui; Yang, Qian; Chen, Qingan; Wang, Yanhui; Xu, Dong; Li, Hezong; Zhang, Xiliang; Harvey, Christopher M.; Liu, Jiwei

doi: 10.1108/ilt-03-2022-0067pmid: N/A

This study aims to investigate the effects of graphite-MoS2 composite solid lubricant on the tribological properties of copper-based bearing materials under dry conditions.Design/methodology/approachThe mixture of Graphite-MoS2 was inlaid in ZQSn6-6–3 tin bronze and ZQAl9-4 aluminum bronze matrix. These copper-embedded self-lubricating bearing materials were considered in friction pairs with 2Cr13 stainless steel, and their tribological properties were studied by using an MM200 wear test machine.FindingsThe results show that the friction coefficients and wear rates of copper-embedded self-lubricating bearing materials are lower than those of the ordinary copper-based bearing materials. The wear performance of the tin bronze inlaid self-lubricating bearing material is better than that of the aluminum bronze inlaid self-lubricating bearing material. The wear mechanism of the tin bronze bearing material is mainly adhesive wear, and that of the aluminum bronze bearing material is mainly grinding wear, oxidation wear and adhesive wear. The copper-embedded self-lubricating bearing materials had no obvious abrasion, whereas the aluminum bronze inlaid self-lubricating bearing material exhibited deep furrows and obvious abrasion under high loads.Originality/valueThese results are helpful for the application of copper-embedded self-lubricating bearing materials.

Lang, XuJin; Wang, Liping; Du, Xin; Li, Lixia; Zhang, Dongya

doi: 10.1108/ilt-04-2022-0140pmid: N/A

This paper aims to synthesize a novel alkanolamine borate and explore the performance of as a copper wire drawing oil.Design/methodology/approachIn this paper, a copper wire drawing oil (CU-KL) was formulated by using a novel alkanolamine borate, naphthenic base oil, fatty alcohol polyoxyethylene ether and palm oil. The tribological performance of CU-KL and commercial copper wire drawing oils (CU-DRB and CU-8010) was investigatedFindingsUnder applied loads of 5 N-15 N, the average friction coefficient of CU-KL was 29.4%, 5.4% and 25.3% lower than that of CU-DRB, respectively. At sliding speed of 1000–5000 rpm, the average friction coefficient of CU-KL was reduced by 14.3%, 6% and 10.3% compared with CU-DRB, respectively. Through scanning electron microscope and energy dispersive spectrometry, CU-KL can form B-containing compound at the contact interface, which could synergistically enhance the lubrication effect and improve the wear resistance.Originality/valueThe properties of CU-KL under different test condition were studied, and the findings are of great significance for the application of alkanolamine borate in copper wire drawing oil.

Kuang, Xin; Yin, Bifeng; Wang, Jian; Jia, Hekun; Xu, Bo

doi: 10.1108/ilt-12-2021-0464pmid: N/A

The purpose of this paper is to evaluate the dispersion stability and the wear properties of lubricating oil blends added with modified nanometer cerium oxide (CeO2) at high temperature.Design/methodology/approachIn this paper, CeO2 was self-made and it was chemically modified. The dispersion stability of CeO2 in lubricating oil was studied. And the wear test of lubricating oil blends added with modified CeO2 was carried out at high temperature.FindingsThe results showed that CeO2 was successfully modified by oleic acid and stearic acid. The dispersion stability of modified CeO2 in lubricating oil was improved. Adding modified nano-CeO2 with the concentration less than 50 ppm into the lubricating oil can improve the wear properties of friction pairs in different extent. With the increase of the amount of CeO2, the wear properties increased first and then decreased. The lubricating oil blend added with 25 ppm CeO2 has the best wear properties.Originality/valueThe raw material CeO2 in this paper is self-made and its shape and size are well controlled. Research on the addition of nano-CeO2 to the engine low viscosity finished lubricants is lacking. It is of great significance to study the dispersion stability and tribological properties of nano-lubricants under the new background of low viscosity of lubricating oil and close to the real engine working conditions. It has certain significance to promote the development of nano-lubricants for engines.

Li, Biao; Sun, Jun; Wang, Hu; Zhang, Xiao

doi: 10.1108/ilt-12-2021-0476pmid: N/A

Under the action of many factors, the shaft of the shaft-journal bearing system inevitably moves along the axis direction at work, which will lead to the axial movement of journal in the bearing. However, at present, only the dynamic and squeezing effects caused by the relative rotation and squeezing motion between the journal and the bearing surfaces are considered in the lubrication analysis of misaligned journal bearing and the axial movement of journal in the actual use of bearing is not considered. The purpose of this paper is to analyze the lubrication of journal bearing considering the axial movement of journal.Design/methodology/approachTaking the shaft-journal bearing system as the research object, a hydrodynamic lubrication model of journal bearing is established considering the axial movement and misalignment of journal. The finite difference method is used to solve the Reynolds equation for the lubrication analysis.FindingsThe axial movement of journal has a significant influence on the lubrication characteristics of misaligned journal bearing. The larger the misalignment angles of journal or the eccentricity of bearing, the greater the influence of the axial movement of journal on the lubrication performance of bearing. The lower the speed of bearing or the smaller the clearance of bearing, the more significant the influence of the axial movement of journal on the lubrication performance of bearing is.Originality/valueThe influence of the axial movement of journal on the lubrication performance of journal bearing is studied under different misalignment angles of journal, working conditions and clearances of bearing. The results of this paper are helpful to the design and research of the lubrication performance of journal bearing.

Guan, Dong; Chen, Zhengrong

doi: 10.1108/ilt-04-2022-0109pmid: N/A

Because of the specific structure and working mechanism, piston speed is only half of its shaft, which causes severally friction between piston and cylinder. Therefore, the main purpose of this paper is to investigate the friction and wear characteristics of the incomplete spherical piston in spherical pump comprehensively. Finally, to search the low-friction and wear-resistance structural pattern of the piston, and enhance the durability of spherical pump.Design/methodology/approachThe non-linear frictional moment model for incomplete spherical piston in spherical pump was derivated quantificationally. Parameter sensitivity analyses were conducted to find the low-friction structural pattern of the piston. The theoretical wear model of piston–cylinder pair is proposed as well.FindingsTo reduce the frictional moment between incomplete piston and cylinder, the optimised diameter ratio between piston pin and piston should be 0.12 based on the parameter sensitivity analyses. The maximum frictional moment is approximately 2.5 times of the minimum. The total efficiency should be considered synthetically based on the thickness of specific working medium.Originality/valueThe proposed non-linear frictional moment model offers the quantitative estimations. Parameter sensitivity analyses were conducted to find the low-friction structural pattern of the piston. The wear behaviours of the piston and cylinder were analysed to investigate the wear characteristics of the piston.

M., Kanagaraj; S., Babu; Raj, Sudhan; N., Jonah; Fekete, Gusztáv; T.V., Christy

doi: 10.1108/ilt-03-2022-0068pmid: N/A

The main purpose of this study in the field of automotive brake friction material is to find an effective material to replace the environmentally hazardous copper in the brake pad formulation.Design/methodology/approachCu is used as functional filler in various forms in the friction material formulation. Because of its hazardous impact to the aquatic life, a suitable replacement of Cu is the main focus of this research. Three novel friction composite materials using ground granulated blast furnace slag (GGBFS) as a suitable alternative for Cu were developed by increasing its Wt.% from 5% to 15% in the step of 5%.FindingsThe physical, mechanical and chemical properties of the developed friction composites were tested as per the industrial standards. The tribological properties were analyzed as per SAE J661 standard using the chase test rig. Initial studies revealed that the friction composite having 5% GGBFS exhibited better physical, mechanical and chemical properties with excellent frictional performance having minimal fluctuations even at higher temperatures. Nonetheless, the results showed that the friction composite containing 15 Wt.% GGBFS revealed a better wear resistance property compared with the other two composites due to the tribo lubricating layer formation at the frictional interface. Scanning electron microscope analysis was performed to understand the wear mechanism and tribo layer formations through topography studies.Originality/valueThis paper explains the influence of GGBFS as a replacement of barytes in brake pads formulation to enhance the tribological performance.