B. Rakhadilov, D. Kakimzhanov, D. Buitkenov, R. Kozhanova, L. Zhurerova, Zhuldyz Sagdoldina
This work is aimed at obtaining gradient coating of aluminum oxide (Al2O3) by detonation spraying. The influence of technological parameters of spraying on the formation of structure, phase composition. mechanical, and tribological characteristics of Al2O3 coatings have been investigated. It was determined that coatings obtained from the same raw powder materials under different technological conditions show different structural and phase characteristics. X-ray diffraction analysis showed that when the barrel is filled with gas mixture by 56%, the coating with the main phase α-Al2O3 is formed, and when the barrel is filled with gas mixture by 63%, the coating with the main phase γ-Al2O3, which is relatively more ductile than α-Al2O3, is formed. It is determined that the α-Al2O3 formed mainly on the surface provides good wear resistance. The bottom layer composed of γ-Al2O3 phase, which is relatively more ductile than α-Al2O3, provides good adhesion of the coating to the substrate. Tribological study showed that the coating obtained at 56% of filling shows good wear resistance compared to other samples. At 63% of filling the results of scratch test showed good adhesive strength. By varying the technological mode of detonation sputtering (56%, 53%, and 63%), Al2O3 coating with gradient structure was obtained, in which γ-Al2O3 smoothly transitions to α-Al2O3 from the substrate to the surface. The hardness of the coatings was found to increase smoothly from substrate to surface (12.4–14.2 GPa).
{"title":"Tribological and Mechanical Properties of Gradient Coating on Al2O3-Based Coating Produced by Detonation Spraying Methods","authors":"B. Rakhadilov, D. Kakimzhanov, D. Buitkenov, R. Kozhanova, L. Zhurerova, Zhuldyz Sagdoldina","doi":"10.1155/2023/1520135","DOIUrl":"https://doi.org/10.1155/2023/1520135","url":null,"abstract":"This work is aimed at obtaining gradient coating of aluminum oxide (Al2O3) by detonation spraying. The influence of technological parameters of spraying on the formation of structure, phase composition. mechanical, and tribological characteristics of Al2O3 coatings have been investigated. It was determined that coatings obtained from the same raw powder materials under different technological conditions show different structural and phase characteristics. X-ray diffraction analysis showed that when the barrel is filled with gas mixture by 56%, the coating with the main phase α-Al2O3 is formed, and when the barrel is filled with gas mixture by 63%, the coating with the main phase γ-Al2O3, which is relatively more ductile than α-Al2O3, is formed. It is determined that the α-Al2O3 formed mainly on the surface provides good wear resistance. The bottom layer composed of γ-Al2O3 phase, which is relatively more ductile than α-Al2O3, provides good adhesion of the coating to the substrate. Tribological study showed that the coating obtained at 56% of filling shows good wear resistance compared to other samples. At 63% of filling the results of scratch test showed good adhesive strength. By varying the technological mode of detonation sputtering (56%, 53%, and 63%), Al2O3 coating with gradient structure was obtained, in which γ-Al2O3 smoothly transitions to α-Al2O3 from the substrate to the surface. The hardness of the coatings was found to increase smoothly from substrate to surface (12.4–14.2 GPa).","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"32 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139227465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates the broaching process of phosphor-bronze (C54400) under different cutting conditions, and the influential factors on cutting force and surface quality are studied. The simulated cutting force implementing the force model based on the energy components also agrees with the results of experiments. In the first part, different cutting velocities of VC = 5, 10, 15, and 20 m/min are studied. In the second part, harmonic vibrations in the form of a sine wave with precise amplitude (A = 1 m/min) and frequencies (F = 55, 65, 85, and 95 Hz) are added in the direction of the cutting velocity. The results revealed that an increase in the cutting velocity from 5 to 20 m/min results in a 40% enhancement in surface quality and a 20% decrease in the cutting force. Additionally, harmonic vibrations of higher frequencies can also contribute to a 35% higher surface quality and a 20% lower cutting force. This study will ultimately improve productivity in industries where broaching is considered the main manufacturing approach, such as automotive and aerospace, in which precision and accuracy are of paramount importance.
{"title":"Investigation on the Cutting Force and Surface Quality in Harmonically Vibrated Broaching (HVB)","authors":"Amirreza Mohammadian, Mahdi Sadeqi Bajestani","doi":"10.1155/2023/9917497","DOIUrl":"https://doi.org/10.1155/2023/9917497","url":null,"abstract":"This paper investigates the broaching process of phosphor-bronze (C54400) under different cutting conditions, and the influential factors on cutting force and surface quality are studied. The simulated cutting force implementing the force model based on the energy components also agrees with the results of experiments. In the first part, different cutting velocities of VC = 5, 10, 15, and 20 m/min are studied. In the second part, harmonic vibrations in the form of a sine wave with precise amplitude (A = 1 m/min) and frequencies (F = 55, 65, 85, and 95 Hz) are added in the direction of the cutting velocity. The results revealed that an increase in the cutting velocity from 5 to 20 m/min results in a 40% enhancement in surface quality and a 20% decrease in the cutting force. Additionally, harmonic vibrations of higher frequencies can also contribute to a 35% higher surface quality and a 20% lower cutting force. This study will ultimately improve productivity in industries where broaching is considered the main manufacturing approach, such as automotive and aerospace, in which precision and accuracy are of paramount importance.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"1 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45995284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Rakhadilov, D. Kakimzhanov, M. Dautbekov, Zhuldyz Sagdoldina, M. Adylkanova, R. Abylkalykova
In this work, the influence of spray parameters on the formation of the microstructure, phase composition, and the tribological properties of detonation flame sprayed coatings was studied. It was determined that the chemical composition of Cr3C2-NiCr coatings during detonation spraying depends on the degree of filling the barrel with an explosive gas mixture. The degree of filling the barrel with an explosive gas mixture at 73% leads to a decrease in the content of carbide phases, and at 57% filling of the barrel, an increase in carbide phases is observed. It is established that the decrease of the filling degree leads to the increase of hardness and wear resistance of the Cr3C2-NiCr coatings since the hardness and wear resistance of the coating material deposited at 57% is higher than at 65% and 73%; this is due to the increase in the carbide phase Cr3C2. Detonation flame sprayed Cr3C2-NiCr gradient coatings have been developed in this study, which is carried out by varying the spray parameters. It was found that in the gradient coating, Cr3C2-NiCr carbide phases gradually increase from the depth to the surface. The obtained gradient coating closer to the substrate consists of the CrNi3 phase, while the coating surface consists of CrNi3 and Cr3C2 phases.
{"title":"Influence of Spraying Parameters on the Structure and Tribological Properties of Cr3C2-NiCr Detonation Coatings","authors":"B. Rakhadilov, D. Kakimzhanov, M. Dautbekov, Zhuldyz Sagdoldina, M. Adylkanova, R. Abylkalykova","doi":"10.1155/2023/6684656","DOIUrl":"https://doi.org/10.1155/2023/6684656","url":null,"abstract":"In this work, the influence of spray parameters on the formation of the microstructure, phase composition, and the tribological properties of detonation flame sprayed coatings was studied. It was determined that the chemical composition of Cr3C2-NiCr coatings during detonation spraying depends on the degree of filling the barrel with an explosive gas mixture. The degree of filling the barrel with an explosive gas mixture at 73% leads to a decrease in the content of carbide phases, and at 57% filling of the barrel, an increase in carbide phases is observed. It is established that the decrease of the filling degree leads to the increase of hardness and wear resistance of the Cr3C2-NiCr coatings since the hardness and wear resistance of the coating material deposited at 57% is higher than at 65% and 73%; this is due to the increase in the carbide phase Cr3C2. Detonation flame sprayed Cr3C2-NiCr gradient coatings have been developed in this study, which is carried out by varying the spray parameters. It was found that in the gradient coating, Cr3C2-NiCr carbide phases gradually increase from the depth to the surface. The obtained gradient coating closer to the substrate consists of the CrNi3 phase, while the coating surface consists of CrNi3 and Cr3C2 phases.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46137728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Patrick Opoku-Mensah, James Nana Gyamfi, Adjei Domfeh, Emmanuel Awarikabey, Emmanuela Kwao-Boateng
In this study, the conventional acid-clay method was used to evaluate its potential for recycling waste crankcase lubricating oil (WCLO). The results showed that the acid-clay method was effective in re-refining the WCLO and returning the oil to a quality comparable to oils produced from fresh lube oil stocks. This method has been reported to account for around 90% of the global waste crankcase lubricating oil treatment and is considered to be an inexpensive process. The results revealed that the acid-clay method improved the viscosity of the oil at 40°C from 104 cSt to 105.6 cSt. The flash point of the oil was also increased from 192°C in the WCLO to 204°C in the re-refined crankcase lubricating oil (RCLO). The water content reduced from 0.01% in the WCLO to 0% in the RCLO, indicating the effectiveness of the acid-clay method in removing water traces from the WCLO. Additionally, the contaminants present in the WCLO were reduced drastically, with iron and aluminum content reduced from 23.0% and 21.0% to 0.0% and 0.0%, respectively. The fuel ingress in the WCLO reduced from 4.0% to 1.0%. However, it was observed that the acid-clay method did not significantly impact the viscosity index, TBN, and density of the oil. The re-refined base oil produced by the acid-clay method can be fortified with appropriate additives and reused in vehicles, reducing environmental pollution, depleting fossil resources, and saving the country’s foreign exchange used in importing fresh lubricating oil.
{"title":"Assessment of the Conventional Acid-Clay Method in Reclaiming Waste Crankcase Lubricating Oil","authors":"Patrick Opoku-Mensah, James Nana Gyamfi, Adjei Domfeh, Emmanuel Awarikabey, Emmanuela Kwao-Boateng","doi":"10.1155/2023/6567607","DOIUrl":"https://doi.org/10.1155/2023/6567607","url":null,"abstract":"In this study, the conventional acid-clay method was used to evaluate its potential for recycling waste crankcase lubricating oil (WCLO). The results showed that the acid-clay method was effective in re-refining the WCLO and returning the oil to a quality comparable to oils produced from fresh lube oil stocks. This method has been reported to account for around 90% of the global waste crankcase lubricating oil treatment and is considered to be an inexpensive process. The results revealed that the acid-clay method improved the viscosity of the oil at 40°C from 104 cSt to 105.6 cSt. The flash point of the oil was also increased from 192°C in the WCLO to 204°C in the re-refined crankcase lubricating oil (RCLO). The water content reduced from 0.01% in the WCLO to 0% in the RCLO, indicating the effectiveness of the acid-clay method in removing water traces from the WCLO. Additionally, the contaminants present in the WCLO were reduced drastically, with iron and aluminum content reduced from 23.0% and 21.0% to 0.0% and 0.0%, respectively. The fuel ingress in the WCLO reduced from 4.0% to 1.0%. However, it was observed that the acid-clay method did not significantly impact the viscosity index, TBN, and density of the oil. The re-refined base oil produced by the acid-clay method can be fortified with appropriate additives and reused in vehicles, reducing environmental pollution, depleting fossil resources, and saving the country’s foreign exchange used in importing fresh lubricating oil.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47197729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Al-Quraan, Olha Ilina, Mukola Kulyk, R. Mnatsakanov, O. Mikosianchyk, Volodumur Melnyk
Self-organization mechanisms of metastable dissipative structures during friction depending on base and oil functional additives for hypoid gears are considered. Research was conducted on a software-hardware complex with simulation of gears’ operation in rolling with slipping conditions in start-stop mode. Indicators of formation of wear-resistant dissipative structures include the following: improvement of antifriction characteristics, lubricant boundary layers’ formation, contact surfaces’ strengthening, and formation of heterogeneous deformation microrelief with a fine-grained structure. The formation of chemically modified boundary layers on 90% of the contact area of tribo-coupling elements ensures an increase in the wear resistance of leading and lagging surfaces by 2 and 1.4 times, respectively. The sclerometry method was used to establish that the formation of dissipative structures when lubricating tribo-coupling elements with various transmission oils can reduce deformation processes in metal near-surface layers by 23%. Highly viscous flavored lubricant with distillate oil and additive composition ensures wear-resistant dissipative structures with active components, including oxygen, sulfur, and phosphorus.
{"title":"Dynamic Processes of Self-Organization in Nonstationary Conditions of Friction","authors":"T. Al-Quraan, Olha Ilina, Mukola Kulyk, R. Mnatsakanov, O. Mikosianchyk, Volodumur Melnyk","doi":"10.1155/2023/6676706","DOIUrl":"https://doi.org/10.1155/2023/6676706","url":null,"abstract":"Self-organization mechanisms of metastable dissipative structures during friction depending on base and oil functional additives for hypoid gears are considered. Research was conducted on a software-hardware complex with simulation of gears’ operation in rolling with slipping conditions in start-stop mode. Indicators of formation of wear-resistant dissipative structures include the following: improvement of antifriction characteristics, lubricant boundary layers’ formation, contact surfaces’ strengthening, and formation of heterogeneous deformation microrelief with a fine-grained structure. The formation of chemically modified boundary layers on 90% of the contact area of tribo-coupling elements ensures an increase in the wear resistance of leading and lagging surfaces by 2 and 1.4 times, respectively. The sclerometry method was used to establish that the formation of dissipative structures when lubricating tribo-coupling elements with various transmission oils can reduce deformation processes in metal near-surface layers by 23%. Highly viscous flavored lubricant with distillate oil and additive composition ensures wear-resistant dissipative structures with active components, including oxygen, sulfur, and phosphorus.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"1 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64799070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New lubricants based on vegetable oil were developed in this study. Different blends of canola oil mixed with fully synthetic two stock engine oils were developed (0, 20%, 40%, 60%, and 80% of synthetic oil). The viscosity of the prepared blends was determined at different temperatures (20°C–80°C). Tribological experiments were conducted to investigate the effect of the newly developed oil on the wear characteristics of mild steel material compared with stainless steel when subjected to adhesive wear loading. The weight loss (WL) and the specific wear rate (SWR) of the mild steel using each of the prepared lubricants were determined. Scanning electron microscopy was used to examine the worn surface of the mild steel. The results revealed that pure canola oil as a lubricant performed competitively against a blend of 80% synthetic and 20% canola oils. The viscosity of the canola oil and its various blends with synthetic oil are controlled by the environmental temperature since an increased temperature reduces the viscosity. Also, the experimental results revealed that operating parameters play the main role in controlling the wear behavior of mild steel since increasing the sliding distances increases the weight loss. The specific wear rate exhibited a steady state after about 5 km sliding distance, and different blends influenced the applied loads and velocity differently. The mixing ratio of canola and syntactic oil was not particularly significant since the pure canola oil exhibited competitive wear performance compared with the blends. However, an intermediate mixing ratio (40%–60% synthetic oil mixed with 60%–40% canola) can produce a slightly low specific wear rate among other things.
{"title":"Tribological Behavior of Mild Steel under Canola Biolubricant Conditions","authors":"A. Shalwan, B. Yousif, F. Alajmi, M. Alajmi","doi":"10.1155/2021/3795831","DOIUrl":"https://doi.org/10.1155/2021/3795831","url":null,"abstract":"New lubricants based on vegetable oil were developed in this study. Different blends of canola oil mixed with fully synthetic two stock engine oils were developed (0, 20%, 40%, 60%, and 80% of synthetic oil). The viscosity of the prepared blends was determined at different temperatures (20°C–80°C). Tribological experiments were conducted to investigate the effect of the newly developed oil on the wear characteristics of mild steel material compared with stainless steel when subjected to adhesive wear loading. The weight loss (WL) and the specific wear rate (SWR) of the mild steel using each of the prepared lubricants were determined. Scanning electron microscopy was used to examine the worn surface of the mild steel. The results revealed that pure canola oil as a lubricant performed competitively against a blend of 80% synthetic and 20% canola oils. The viscosity of the canola oil and its various blends with synthetic oil are controlled by the environmental temperature since an increased temperature reduces the viscosity. Also, the experimental results revealed that operating parameters play the main role in controlling the wear behavior of mild steel since increasing the sliding distances increases the weight loss. The specific wear rate exhibited a steady state after about 5 km sliding distance, and different blends influenced the applied loads and velocity differently. The mixing ratio of canola and syntactic oil was not particularly significant since the pure canola oil exhibited competitive wear performance compared with the blends. However, an intermediate mixing ratio (40%–60% synthetic oil mixed with 60%–40% canola) can produce a slightly low specific wear rate among other things.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"1 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47829605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The tribological behavior of Ni-based WC-Co coatings is analyzed. The coatings were deposited on gray cast iron substrates in a spray and fuse process using SuperJet Eutalloy deposition equipment, varying the oxygen flow conditions in the flame. The crystallographic structure of the coatings was characterized via the X-ray diffraction (XRD) technique. The microhardness was measured on the surface and in cross sections of the coatings by means of a Knoop microhardness tester. The topography and the morphological characteristics of the coatings and the tribo-surfaces were examined using scanning electron microscopy (SEM) and confocal microscopy, while the chemical composition was measured by means of energy-dispersive X-ray spectroscopy (EDS). The tribological behavior of the coatings was examined via a cohesion-adhesion scratch test, using cross sections of the coatings. Furthermore, two wear tests were carried out, using the pin-on-disk method under ASTM G99 standard and an ASTM standard G65 sand/rubber wheel abrasion wear test. The wear of the coatings showed a close relationship to the porosity in the metal matrix; since then, in the abrasive wear test, a high porosity is related with lower hardness in the coatings; likewise, a low hardness is related with a high wear.
{"title":"Tribological Behavior of Ni-Based WC-Co Coatings Deposited via Spray and Fuse Technique Varying the Oxygen Flow","authors":"H. Jiménez, J. Olaya, J. Alfonso","doi":"10.1155/2021/8898349","DOIUrl":"https://doi.org/10.1155/2021/8898349","url":null,"abstract":"The tribological behavior of Ni-based WC-Co coatings is analyzed. The coatings were deposited on gray cast iron substrates in a spray and fuse process using SuperJet Eutalloy deposition equipment, varying the oxygen flow conditions in the flame. The crystallographic structure of the coatings was characterized via the X-ray diffraction (XRD) technique. The microhardness was measured on the surface and in cross sections of the coatings by means of a Knoop microhardness tester. The topography and the morphological characteristics of the coatings and the tribo-surfaces were examined using scanning electron microscopy (SEM) and confocal microscopy, while the chemical composition was measured by means of energy-dispersive X-ray spectroscopy (EDS). The tribological behavior of the coatings was examined via a cohesion-adhesion scratch test, using cross sections of the coatings. Furthermore, two wear tests were carried out, using the pin-on-disk method under ASTM G99 standard and an ASTM standard G65 sand/rubber wheel abrasion wear test. The wear of the coatings showed a close relationship to the porosity in the metal matrix; since then, in the abrasive wear test, a high porosity is related with lower hardness in the coatings; likewise, a low hardness is related with a high wear.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"2021 1","pages":"1-10"},"PeriodicalIF":2.6,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42445301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a state of the art on computer simulation and prediction of wear in mechanical components is reviewed. Past and recent developments as well as approaches employed in the simulation and prediction of wear are reviewed. In particular, the wear models, contact analysis schemes, and wear evolution prediction procedures as well as their application to the mechanical components (including cam-follower, gears, bearings, and cylinder/piston/piston ring wear) are reviewed. Recommendations and suggestions on possible directions for further research studies are also presented.
{"title":"Computer Simulation/Prediction of Wear in Mechanical Components","authors":"S. Mukras","doi":"10.1155/2020/8867351","DOIUrl":"https://doi.org/10.1155/2020/8867351","url":null,"abstract":"In this paper, a state of the art on computer simulation and prediction of wear in mechanical components is reviewed. Past and recent developments as well as approaches employed in the simulation and prediction of wear are reviewed. In particular, the wear models, contact analysis schemes, and wear evolution prediction procedures as well as their application to the mechanical components (including cam-follower, gears, bearings, and cylinder/piston/piston ring wear) are reviewed. Recommendations and suggestions on possible directions for further research studies are also presented.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"2020 1","pages":"1-15"},"PeriodicalIF":2.6,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/8867351","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43968710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carlo Alberto Niccolini Marmont Du Haut Champ, F. Stefani, P. Silvestri
The aim of the present research is to characterize both experimentally and numerically journal bearings with low radial clearances for rotors in small-scale applications (e.g., microgas turbines); their diameter is in the order of ten millimetres, leading to very small dimensional clearances when the typical relative ones (order of 1/1000) are employed; investigating this particular class of journal bearings under static and dynamic loading conditions represents something unexplored. To this goal, a suitable test rig was designed and the performance of its bearings was investigated under steady load. For the sake of comparison, numerical simulations of the lubrication were also performed by means of a simplified model. The original test rig adopted is a commercial rotor kit (RK), but substantial modifications were carried out in order to allow significant measurements. Indeed, the relative radial clearance of RK4 RK bearings is about 2/100, while it is around 1/1000 in industrial bearings. Therefore, the same original RK bearings are employed in this new test rig, but a new shaft was designed to reduce their original clearance. The new custom shaft allows to study bearing behaviour for different clearances, since it is equipped with interchangeable journals. Experimental data obtained by this test rig are then compared with further results of more sophisticated simulations. They were carried out by means of an in-house developed finite element (FEM) code, suitable for thermoelasto-hydrodynamic (TEHD) analysis of journal bearings both in static and dynamic conditions. In this paper, bearing static performances are studied to assess the reliability of the experimental journal location predictions by comparing them with the ones coming from already validated numerical codes. Such comparisons are presented both for large and small clearance bearings of original and modified RKs, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance 8/1000), as expected. In comparison with two-dimensional lubrication analysis, three-dimensional simulation improves prediction of journal location and correlation with experimental results.
{"title":"Experimental and Numerical Investigation about Small Clearance Journal Bearings under Static Load Conditions","authors":"Carlo Alberto Niccolini Marmont Du Haut Champ, F. Stefani, P. Silvestri","doi":"10.1155/2020/8844879","DOIUrl":"https://doi.org/10.1155/2020/8844879","url":null,"abstract":"The aim of the present research is to characterize both experimentally and numerically journal bearings with low radial clearances for rotors in small-scale applications (e.g., microgas turbines); their diameter is in the order of ten millimetres, leading to very small dimensional clearances when the typical relative ones (order of 1/1000) are employed; investigating this particular class of journal bearings under static and dynamic loading conditions represents something unexplored. To this goal, a suitable test rig was designed and the performance of its bearings was investigated under steady load. For the sake of comparison, numerical simulations of the lubrication were also performed by means of a simplified model. The original test rig adopted is a commercial rotor kit (RK), but substantial modifications were carried out in order to allow significant measurements. Indeed, the relative radial clearance of RK4 RK bearings is about 2/100, while it is around 1/1000 in industrial bearings. Therefore, the same original RK bearings are employed in this new test rig, but a new shaft was designed to reduce their original clearance. The new custom shaft allows to study bearing behaviour for different clearances, since it is equipped with interchangeable journals. Experimental data obtained by this test rig are then compared with further results of more sophisticated simulations. They were carried out by means of an in-house developed finite element (FEM) code, suitable for thermoelasto-hydrodynamic (TEHD) analysis of journal bearings both in static and dynamic conditions. In this paper, bearing static performances are studied to assess the reliability of the experimental journal location predictions by comparing them with the ones coming from already validated numerical codes. Such comparisons are presented both for large and small clearance bearings of original and modified RKs, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance 8/1000), as expected. In comparison with two-dimensional lubrication analysis, three-dimensional simulation improves prediction of journal location and correlation with experimental results.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"1 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2020-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/8844879","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64753243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study introduces chaulmoogra oil as a base stock for lubricant formulation. The tribological properties of chaulmoogra oil are evaluated by quantitative structure-property relation (QSPR) technique using the molecular modelling package Spartan 18. The quantum chemical calculations were performed on a typical molecule of chaulmoogra oil and its constituent fatty acids. The orbital energy gap of the constituent fatty acids in chaulmoogra oil is 7.37 eV and that of chaulmoogra oil molecule is 6.8 eV, which is less than that of the lauric acid, the main constituent of coconut oil (7.78 eV). Orbital energy gap predicts a better tribological performance for chaulmoogra oil, and the four ball test result is in agreement with this prediction. Oxidative property of chaulmoogra oil is tested by isothermal thermogravimetric/differential thermal analysis (TGA/DTA) and compared with different oils. Weight gain in oxygen is only 0.02% for chaulmoogra oil and showed better oxidative stability among all other tested oils.
{"title":"Experimental and Molecular Level Analysis of the Tribological and Oxidative Properties of Chaulmoogra Oil","authors":"S. Salaji, N. Jayadas","doi":"10.1155/2020/8821316","DOIUrl":"https://doi.org/10.1155/2020/8821316","url":null,"abstract":"This study introduces chaulmoogra oil as a base stock for lubricant formulation. The tribological properties of chaulmoogra oil are evaluated by quantitative structure-property relation (QSPR) technique using the molecular modelling package Spartan 18. The quantum chemical calculations were performed on a typical molecule of chaulmoogra oil and its constituent fatty acids. The orbital energy gap of the constituent fatty acids in chaulmoogra oil is 7.37 eV and that of chaulmoogra oil molecule is 6.8 eV, which is less than that of the lauric acid, the main constituent of coconut oil (7.78 eV). Orbital energy gap predicts a better tribological performance for chaulmoogra oil, and the four ball test result is in agreement with this prediction. Oxidative property of chaulmoogra oil is tested by isothermal thermogravimetric/differential thermal analysis (TGA/DTA) and compared with different oils. Weight gain in oxygen is only 0.02% for chaulmoogra oil and showed better oxidative stability among all other tested oils.","PeriodicalId":44668,"journal":{"name":"Advances in Tribology","volume":"2020 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2020-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/8821316","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44431973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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