H. Dhiflaoui, Mohamed Ali Hajjaji, A. Hajjaji, L. Khezami, A. Karrech, B. Bessais, Ahmed Ben Cheikh Larbia, M. Amlouk
In the present study, the adhesion of TiO2 nanotubes (TiO2-NTs) to thicker substrates was improved by decorating them with metallic Ag nanoparticles (NPs) using the photo-reduction process. The obtained coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM). X-ray diffraction (XRD) confirmed that all TiO2-NTs crystallized in anatase after annealing at 400°C regardless of the anodization potential. The scanning electron microscopy (SEM) indicated that the TiO2-NTs were uniformly distributed on the substrate with an ordered and vertically aligned morphology. It also revealed that the diameter of the TiO2-NTs reached~100 nm. The decoration of TiO2-NTs surface with silver nanoparticles was assessed by transmission electron microscopy (TEM). Moreover, a new scratch test mode called ‘wear mode’ was performed to evaluate the wear resistance of the coatings. Results obtained by the scratch tests proved that the decorated coating with Ag nanoparticles improved the interfacial adhesion. The friction coefficient decreased from 0.65 to 0.45 when pure TiO2 was decorated with 10 min-Ag-NPs.The wear behavior was studied using a multi-pass scratch test. It was found that the wear volume reduced with the incorporation of Ag nanoparticles. The study of the damage mechanisms showed visco-elastic plastic deformation in the pure TiO2 coating.
{"title":"Enhanced interfacial adhesion of TiO2 nanotubes (TiO2-NTs) decorated with Ag Silver nanoparticles (Ag-NPs) prepared by photo-reduction process","authors":"H. Dhiflaoui, Mohamed Ali Hajjaji, A. Hajjaji, L. Khezami, A. Karrech, B. Bessais, Ahmed Ben Cheikh Larbia, M. Amlouk","doi":"10.1115/1.4062485","DOIUrl":"https://doi.org/10.1115/1.4062485","url":null,"abstract":"\u0000 In the present study, the adhesion of TiO2 nanotubes (TiO2-NTs) to thicker substrates was improved by decorating them with metallic Ag nanoparticles (NPs) using the photo-reduction process. The obtained coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM). X-ray diffraction (XRD) confirmed that all TiO2-NTs crystallized in anatase after annealing at 400°C regardless of the anodization potential. The scanning electron microscopy (SEM) indicated that the TiO2-NTs were uniformly distributed on the substrate with an ordered and vertically aligned morphology. It also revealed that the diameter of the TiO2-NTs reached~100 nm. The decoration of TiO2-NTs surface with silver nanoparticles was assessed by transmission electron microscopy (TEM). Moreover, a new scratch test mode called ‘wear mode’ was performed to evaluate the wear resistance of the coatings. Results obtained by the scratch tests proved that the decorated coating with Ag nanoparticles improved the interfacial adhesion. The friction coefficient decreased from 0.65 to 0.45 when pure TiO2 was decorated with 10 min-Ag-NPs.The wear behavior was studied using a multi-pass scratch test. It was found that the wear volume reduced with the incorporation of Ag nanoparticles. The study of the damage mechanisms showed visco-elastic plastic deformation in the pure TiO2 coating.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47595763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A prediction model of gearbox power loss based on dimensionless analysis is proposed. First, the dimensional model of gearbox power loss is established based on similarity criterion, dimensional harmony principle and fluid mechanics p theorem. Then, the experimental study is carried out on a power loss test bench. Based on the measured data and multiple linear regression method, the coefficients of the influencing factors are calculated, including gear design parameters, lubrication oil parameters, and operating conditions. To validate the prediction model, the gear pairs were test under various operating conditions and two new gear sets with different helical angles were also included. The comparison results show good consistency between the measured data and predicted values. The proposed model can be employed to assist gearbox design and improve the gearbox efficiency.
{"title":"A Theoretical and Experimental Study on the Power Loss of Gearbox Based on Dimensionless Analysis","authors":"Dong Guo, G. Wen, Yawen Wang, Dongyuan Luo","doi":"10.1115/1.4062449","DOIUrl":"https://doi.org/10.1115/1.4062449","url":null,"abstract":"\u0000 A prediction model of gearbox power loss based on dimensionless analysis is proposed. First, the dimensional model of gearbox power loss is established based on similarity criterion, dimensional harmony principle and fluid mechanics p theorem. Then, the experimental study is carried out on a power loss test bench. Based on the measured data and multiple linear regression method, the coefficients of the influencing factors are calculated, including gear design parameters, lubrication oil parameters, and operating conditions. To validate the prediction model, the gear pairs were test under various operating conditions and two new gear sets with different helical angles were also included. The comparison results show good consistency between the measured data and predicted values. The proposed model can be employed to assist gearbox design and improve the gearbox efficiency.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42087279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aims to investigate the lubricating performance of the bubbly oil. Due to space limitation, the work is divided into two parts. Part 1 drew a conclusion that the bubbly oil under high shear rate appears a lower viscosity than the non-aerated oil, and the air volume fraction can be adjusted conveniently to reach a high value. Based on this, in Part 2, we intend to explore the feasibility of using the bubbly oil in lubricating high-speed bearings. Here, we select a step thrust bearing as object and analyze its static characteristics under the bubbly oil lubrication. A test rig for the high-speed step thrust bearing was developed to measure the static characteristics of the bearing under the bubbly oil lubrication. The lubrication models for the hydrodynamic step thrust bearing were established to predict the bearing static characteristics. The results show that the static characteristics parameters of the bearing under the bubbly oil lubrication are less than those under the non-aerated oil lubrication, and the differences of static characteristics parameters of the bearing between the non-aerated oil lubrication and the bubbly oil one become larger with the increase of air volume fraction and the external load, especially at a higher speed.
{"title":"Study on Lubricating Performance of the Bubbly Oil under high Shear Rate, Part 2: Application Study in High-Speed Bearing","authors":"Shuyun Jiang, Shaohua Li, Feida Zhou, Xiaohui Lin","doi":"10.1115/1.4062407","DOIUrl":"https://doi.org/10.1115/1.4062407","url":null,"abstract":"\u0000 This paper aims to investigate the lubricating performance of the bubbly oil. Due to space limitation, the work is divided into two parts. Part 1 drew a conclusion that the bubbly oil under high shear rate appears a lower viscosity than the non-aerated oil, and the air volume fraction can be adjusted conveniently to reach a high value. Based on this, in Part 2, we intend to explore the feasibility of using the bubbly oil in lubricating high-speed bearings. Here, we select a step thrust bearing as object and analyze its static characteristics under the bubbly oil lubrication. A test rig for the high-speed step thrust bearing was developed to measure the static characteristics of the bearing under the bubbly oil lubrication. The lubrication models for the hydrodynamic step thrust bearing were established to predict the bearing static characteristics. The results show that the static characteristics parameters of the bearing under the bubbly oil lubrication are less than those under the non-aerated oil lubrication, and the differences of static characteristics parameters of the bearing between the non-aerated oil lubrication and the bubbly oil one become larger with the increase of air volume fraction and the external load, especially at a higher speed.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41335722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuo Wang, Tao Shao, Tonghai Wu, T. Sarkodie-Gyan, Yaguo Lei
Wear debris analysis (WDA) enables the provision of essential information towards the monitoring of machine fault diagnosis and the analysis of wear mechanism. However, this experience-based technology has not yet been automated for the identification of similar particle types due to the small number of samples and highly-dispersed features. To address this problem, a knowledge-guided convolutional neural network (KG-CNN) model is developed to focus on two representative severe wear particles: fatigue and severe sliding particles that have highly similar contours but weakly discriminative surfaces. The height images of particle surfaces are adopted as the initial objective. Characterized by typical particle features, the empirical WDA knowledge is represented into the feature-marked images, and further automatically learned by a U-Net-based knowledge extraction network. By weighting with the U-Net output, a knowledge-guided particle classification network is constructed to identify similar particles under a small number of samples. With this methodology, the empirical WDA knowledge is transferred to guide the classification network for locating the discriminative features in particle height images. Thirty sets of fatigue and severe sliding particles are acquired from wear tests as the training and testing samples. For verification, the network kernel is visualized to trace the particle feature propagation in the classification. Experimental results reveal that the proposed method can accurately identify fault particles that acquired from wear tests.
{"title":"Knowledge-guided CNN Model for Similar 3D Wear Debris Identification with Small Number of Samples","authors":"Shuo Wang, Tao Shao, Tonghai Wu, T. Sarkodie-Gyan, Yaguo Lei","doi":"10.1115/1.4062370","DOIUrl":"https://doi.org/10.1115/1.4062370","url":null,"abstract":"\u0000 Wear debris analysis (WDA) enables the provision of essential information towards the monitoring of machine fault diagnosis and the analysis of wear mechanism. However, this experience-based technology has not yet been automated for the identification of similar particle types due to the small number of samples and highly-dispersed features. To address this problem, a knowledge-guided convolutional neural network (KG-CNN) model is developed to focus on two representative severe wear particles: fatigue and severe sliding particles that have highly similar contours but weakly discriminative surfaces. The height images of particle surfaces are adopted as the initial objective. Characterized by typical particle features, the empirical WDA knowledge is represented into the feature-marked images, and further automatically learned by a U-Net-based knowledge extraction network. By weighting with the U-Net output, a knowledge-guided particle classification network is constructed to identify similar particles under a small number of samples. With this methodology, the empirical WDA knowledge is transferred to guide the classification network for locating the discriminative features in particle height images. Thirty sets of fatigue and severe sliding particles are acquired from wear tests as the training and testing samples. For verification, the network kernel is visualized to trace the particle feature propagation in the classification. Experimental results reveal that the proposed method can accurately identify fault particles that acquired from wear tests.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44277043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Morinoye O Folorunso, Michael Watson, Alan Martin, Jacob W Whittle, Graham Sutherland, R. Lewis
Predicting friction at the wheel rail interface is a key problem in the rail industry. Current forecasts give regional level predictions, however, it is well known that friction conditions can change dramatically over a few hundred metres. In this study we aimed to produce a proof-of-concept friction prediction tool which could be used on trains to give an indication of the limiting friction present at a precise location. To this end field data including temperature, humidity, friction and images were collected. These were used to fit a statistical model including effects of local environmental conditions, surroundings and railhead state. The model predicted the friction well with an R2 of 0.97, falling to 0.96 for naive models in cross validation. With images and environmental data collected on a train a real time friction measurement would be possible.
{"title":"A Machine Learning Approach for Real Time Wheel/Rail Interface Friction Estimation","authors":"Morinoye O Folorunso, Michael Watson, Alan Martin, Jacob W Whittle, Graham Sutherland, R. Lewis","doi":"10.1115/1.4062373","DOIUrl":"https://doi.org/10.1115/1.4062373","url":null,"abstract":"\u0000 Predicting friction at the wheel rail interface is a key problem in the rail industry. Current forecasts give regional level predictions, however, it is well known that friction conditions can change dramatically over a few hundred metres. In this study we aimed to produce a proof-of-concept friction prediction tool which could be used on trains to give an indication of the limiting friction present at a precise location. To this end field data including temperature, humidity, friction and images were collected. These were used to fit a statistical model including effects of local environmental conditions, surroundings and railhead state. The model predicted the friction well with an R2 of 0.97, falling to 0.96 for naive models in cross validation. With images and environmental data collected on a train a real time friction measurement would be possible.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42850353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi Zhu, Zijun Yuan, M. Khonsari, Shuming Zhao, Huayong Yang
The wear performance of an additively manufactured part is crucial to ensure the component's functionality and reliability. Nevertheless, wear prediction is arduous due to numerous influential factors in both the manufacturing procedure and contact conditions. Machine learning offers a facile path to predict mechanical properties if sufficient datasets is available, without which it is very challenging to attain a high prediction accuracy. In this work, high-accuracy wear prediction of 316L stainless steel parts fabricated using laser powder bed fusion and in-situ surface modification is achieved based on only 54 data using a combination of an improved machine learning algorithm and data augmentation. A new modification temperature ratio was introduced for data augmentation. Four common machine learning algorithms and sparrow search algorithm optimized back propagation neural network was conducted and compared. The results indicated that the prediction accuracy of all algorithms was improved after data augmentation, while the improved machine learning algorithm achieved the highest prediction accuracy (R2=0.978). Such an approach is applicable to predict other systematically complex properties of parts fabricated using other additive manufacturing technology.
{"title":"Small-dataset machine learning for wear prediction of laser powder bed fusion fabricated steel","authors":"Yi Zhu, Zijun Yuan, M. Khonsari, Shuming Zhao, Huayong Yang","doi":"10.1115/1.4062368","DOIUrl":"https://doi.org/10.1115/1.4062368","url":null,"abstract":"\u0000 The wear performance of an additively manufactured part is crucial to ensure the component's functionality and reliability. Nevertheless, wear prediction is arduous due to numerous influential factors in both the manufacturing procedure and contact conditions. Machine learning offers a facile path to predict mechanical properties if sufficient datasets is available, without which it is very challenging to attain a high prediction accuracy. In this work, high-accuracy wear prediction of 316L stainless steel parts fabricated using laser powder bed fusion and in-situ surface modification is achieved based on only 54 data using a combination of an improved machine learning algorithm and data augmentation. A new modification temperature ratio was introduced for data augmentation. Four common machine learning algorithms and sparrow search algorithm optimized back propagation neural network was conducted and compared. The results indicated that the prediction accuracy of all algorithms was improved after data augmentation, while the improved machine learning algorithm achieved the highest prediction accuracy (R2=0.978). Such an approach is applicable to predict other systematically complex properties of parts fabricated using other additive manufacturing technology.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45005608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal rubber (MR) is a kind of elastic porous material with a complex and disordered internal structure, which results in wear characteristics that can only rely on tests but cannot meet the engineering application. This paper presents an exciting method for studying wear characteristics based on its virtual fabrication technology. By developing the intricate internal multipoint random contact mesh model of MR, a virtual real-time dynamic tracking contact point in a different state is captured. A thorough investigation is conducted into the contact point properties, point distribution, and the interaction of discrete contact points in MR interior space. Accordingly, a cross-scale micro-motion wear study method from micromorphology to macroscopic performance is proposed. The continuous wear cycle of MR is discretized into multiple single-turn metal wire elements by applying the principle of equal spacing. A statistical model of internal contact point wear of MR at the microlayer is developed considering the metal wire's single-turn fretting wear prediction model. The cumulative prediction model of macroscopic wear damage of MR is based on the superposition of micro-element interval. Finally, the difference between the mass loss and that obtained from the simulation analysis after performing dynamic loading tests at different cycles was studied and found to be insignificant.
{"title":"Study of cross-scale micro-motion wear characteristics of metallic rubber","authors":"Yonggang Bai, Zhou Huang, Xianjie Shi, Z. Guo, Zihao Huang, Zhiying Ren","doi":"10.1115/1.4062374","DOIUrl":"https://doi.org/10.1115/1.4062374","url":null,"abstract":"\u0000 Metal rubber (MR) is a kind of elastic porous material with a complex and disordered internal structure, which results in wear characteristics that can only rely on tests but cannot meet the engineering application. This paper presents an exciting method for studying wear characteristics based on its virtual fabrication technology. By developing the intricate internal multipoint random contact mesh model of MR, a virtual real-time dynamic tracking contact point in a different state is captured. A thorough investigation is conducted into the contact point properties, point distribution, and the interaction of discrete contact points in MR interior space. Accordingly, a cross-scale micro-motion wear study method from micromorphology to macroscopic performance is proposed. The continuous wear cycle of MR is discretized into multiple single-turn metal wire elements by applying the principle of equal spacing. A statistical model of internal contact point wear of MR at the microlayer is developed considering the metal wire's single-turn fretting wear prediction model. The cumulative prediction model of macroscopic wear damage of MR is based on the superposition of micro-element interval. Finally, the difference between the mass loss and that obtained from the simulation analysis after performing dynamic loading tests at different cycles was studied and found to be insignificant.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46932038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The energy needs of a country cannot be fulfilled by a single source of energy, so the renewable energy sources like solar, wind and hydro energy are widely used throughout the world. In countries where sufficient hydro energy resources are available, the hydropower plants have been installed to produce the electricity. But in countries where the rivers originate from hilly areas (like India and Nepal) have to deal with the losses due the wear caused by the silt particles presented in water. The silt content in water causes the erosion of material in different components of hydro power plant. To avoid these losses thermally sprayed hard surface coatings are widely used as protective layer. This review focuses on the performance of composite coatings based on nickel and tungsten in slurry erosion conditions. A comprehensive investigation of studies conducted on thermally sprayed nickel and tungsten based coatings is discussed in this review paper. The review reveals that HVOF is widely used by different researchers to develop composite coatings. Materials like Ni–20Cr2O3, Ni–Al2O3, Ni-Cr-Si-B, WC-10Co, WC-10Co-Cr, NiCrBSiFe-WC (Co) have been used in different studies to minimize the wear of material in slurry conditions.
{"title":"Performance of thermally sprayed nickel and tungsten based coatings in slurry erosion conditions: A review","authors":"Abhinay Kumar, R. K. Garg, A. Sachdeva","doi":"10.1115/1.4062372","DOIUrl":"https://doi.org/10.1115/1.4062372","url":null,"abstract":"\u0000 The energy needs of a country cannot be fulfilled by a single source of energy, so the renewable energy sources like solar, wind and hydro energy are widely used throughout the world. In countries where sufficient hydro energy resources are available, the hydropower plants have been installed to produce the electricity. But in countries where the rivers originate from hilly areas (like India and Nepal) have to deal with the losses due the wear caused by the silt particles presented in water. The silt content in water causes the erosion of material in different components of hydro power plant. To avoid these losses thermally sprayed hard surface coatings are widely used as protective layer. This review focuses on the performance of composite coatings based on nickel and tungsten in slurry erosion conditions. A comprehensive investigation of studies conducted on thermally sprayed nickel and tungsten based coatings is discussed in this review paper. The review reveals that HVOF is widely used by different researchers to develop composite coatings. Materials like Ni–20Cr2O3, Ni–Al2O3, Ni-Cr-Si-B, WC-10Co, WC-10Co-Cr, NiCrBSiFe-WC (Co) have been used in different studies to minimize the wear of material in slurry conditions.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45786268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nanrong Hu, H. Jia, Bifeng Yin, Zeyuan Zhou, Bo Xu
The elastohydrodynamic model of hydrodynamic air foil bearing has been built to study the influence of rotor speed, the friction coefficient between bearing components, load and other parameters on the foil displacement of hydrodynamic air bearing under steady-state conditions. The static characteristics of hydrodynamic air foil bearing are predicted by using the numerical simulation method. The results show that the radial displacement of the foil is the smallest at both ends of the bearing and the largest at the middle of the bearing, while the top foil changes gently along the width of the bearing away from the maximum pressure. After increasing the rotating speed, the maximum fluid pressure improves and the action position shifts, and the increase of rotating speed has a significant impact on the maximum pressure. improving the friction coefficient μ2 between the bump foil and the bearing sleeve has different effects on the displacement of the foil. When μ1 is 0.1, by promoting μ2, the transverse displacement of the top foil at the pressure peak increases by 20.9%, the longitudinal displacement is reduced by 8.9%, the transverse displacement and the maximum longitudinal negative displacement of the bump foil are decreased by 53.2% and 31.7% respectively. Furthermore, the longitudinal displacement of bump foil at the fixed end has been reduced by increasing the load, and the relative size of the friction coefficient between the components affects the size and direction of the foil displacement at the same load.
{"title":"Prediction of static characteristics of hydrodynamic air foil bearing considering contact and friction between foils","authors":"Nanrong Hu, H. Jia, Bifeng Yin, Zeyuan Zhou, Bo Xu","doi":"10.1115/1.4062369","DOIUrl":"https://doi.org/10.1115/1.4062369","url":null,"abstract":"\u0000 The elastohydrodynamic model of hydrodynamic air foil bearing has been built to study the influence of rotor speed, the friction coefficient between bearing components, load and other parameters on the foil displacement of hydrodynamic air bearing under steady-state conditions. The static characteristics of hydrodynamic air foil bearing are predicted by using the numerical simulation method. The results show that the radial displacement of the foil is the smallest at both ends of the bearing and the largest at the middle of the bearing, while the top foil changes gently along the width of the bearing away from the maximum pressure. After increasing the rotating speed, the maximum fluid pressure improves and the action position shifts, and the increase of rotating speed has a significant impact on the maximum pressure. improving the friction coefficient μ2 between the bump foil and the bearing sleeve has different effects on the displacement of the foil. When μ1 is 0.1, by promoting μ2, the transverse displacement of the top foil at the pressure peak increases by 20.9%, the longitudinal displacement is reduced by 8.9%, the transverse displacement and the maximum longitudinal negative displacement of the bump foil are decreased by 53.2% and 31.7% respectively. Furthermore, the longitudinal displacement of bump foil at the fixed end has been reduced by increasing the load, and the relative size of the friction coefficient between the components affects the size and direction of the foil displacement at the same load.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46037955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this study is to assess the role of the turbulence on the lubrication performances of coupled journal-thrust water-lubricated bearing with micro grooves using a numerical model. The results of the simulation model are compared to the published experimental data to verify the validity of the numerical model. The load capacity, maximum film pressure and local Reynolds number variations with the rotating speed, eccentricity, radial clearance, axial geometric gap and micro groove depth for coupled journal-thrust water-lubricated bearing are examined. Furthermore, the calculated results under the turbulent flow are compared with those under laminar flow for coupled and separate bearings. The results show that the turbulence effect can improve the lubrication performances by enlarging fluid pressure and load capacity of the coupled journal-thrust bearing and the laminar flow assumption is no longer applicable to the actual operating conditions of the water-lubricated bearings at a high rotation speed. In addition, there are existed optimal micro groove depths for both journal bearing and thrust bearing to reach the peak of the load capacity while the optimal micro groove depths for journal bearing and thrust bearing are not the same.
{"title":"Numerical analysis of turbulence effect for coupled journal-thrust water-lubricated bearing with micro grooves","authors":"Tianyou Yang, Jianlin Cai, Liwu Wang, Dongxing Tang, Shouan Chen, Jiaxu Wang","doi":"10.1115/1.4062362","DOIUrl":"https://doi.org/10.1115/1.4062362","url":null,"abstract":"\u0000 The purpose of this study is to assess the role of the turbulence on the lubrication performances of coupled journal-thrust water-lubricated bearing with micro grooves using a numerical model. The results of the simulation model are compared to the published experimental data to verify the validity of the numerical model. The load capacity, maximum film pressure and local Reynolds number variations with the rotating speed, eccentricity, radial clearance, axial geometric gap and micro groove depth for coupled journal-thrust water-lubricated bearing are examined. Furthermore, the calculated results under the turbulent flow are compared with those under laminar flow for coupled and separate bearings. The results show that the turbulence effect can improve the lubrication performances by enlarging fluid pressure and load capacity of the coupled journal-thrust bearing and the laminar flow assumption is no longer applicable to the actual operating conditions of the water-lubricated bearings at a high rotation speed. In addition, there are existed optimal micro groove depths for both journal bearing and thrust bearing to reach the peak of the load capacity while the optimal micro groove depths for journal bearing and thrust bearing are not the same.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42245688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：