Pub Date : 2024-09-10DOI: 10.1177/16878132241272197
Jae-Hyun Kim, Beom-Soo Kim, Dongu Im, Jung-Ho Park, Dong-Joo Moon, Young-Jun Park
We develop a program for predicting bearing performance, including the maximum contact stress, bearing power loss, minimum lubricating film thickness, static safety factor, and dynamic life, and an optimal design for high-speed angular contact ball bearings in aircraft gearboxes using optimization algorithms. A program is developed to predict bearing performance by calculating the loads and displacements of individual balls based on the bearing’s kinematic and static equilibrium equations. Next, an optimization program is developed with non-dominated sorting genetic algorithm III (NSGA-III), wherein calculated bearing performance indicators serve as constraints or objective functions. The performance of individuals within the final Pareto front is evaluated using the inter-criteria correlation (CRITIC) and weighted product methods. The optimization performances of NSGA-III and NSGA-II are compared based on their hypervolume indicators. A solution of the kinematic and static equilibrium equations under the load cases and duty cycles of real aircraft gearboxes is obtained, enhancing the prediction accuracy. Furthermore, optimization, including bearing performance metrics rarely considered in previous studies, is performed. Optimal specifications superior to reference bearings employed in aircraft gearboxes are obtained, enhancing all three objective functions or specific objective functions. The optimization performance of NSGA-III is confirmed to surpass that of conventional NSGA-II.
我们开发了一种预测轴承性能的程序，包括最大接触应力、轴承功率损失、最小润滑膜厚度、静态安全系数和动态寿命，并使用优化算法对飞机齿轮箱中的高速角接触球轴承进行了优化设计。根据轴承的运动学和静态平衡方程，通过计算单个球的载荷和位移，开发了一个预测轴承性能的程序。接着，使用非支配排序遗传算法 III (NSGA-III) 开发了一个优化程序，将计算出的轴承性能指标作为约束条件或目标函数。使用标准间相关性（CRITIC）和加权乘积法评估最终帕累托前沿内个体的性能。根据超体积指标，比较了 NSGA-III 和 NSGA-II 的优化性能。在实际飞机齿轮箱的负载情况和工作周期下，获得了运动和静态平衡方程的解，提高了预测精度。此外，还进行了优化，包括以往研究中很少考虑的轴承性能指标。获得了优于飞机齿轮箱中使用的参考轴承的最佳规格，增强了所有三个目标函数或特定目标函数。经证实，NSGA-III 的优化性能超过了传统的 NSGA-II。
{"title":"Optimization of high-speed angular contact ball bearing for aircraft gearbox utilizing an evolutionary multi-objective algorithm, NSGA-III","authors":"Jae-Hyun Kim, Beom-Soo Kim, Dongu Im, Jung-Ho Park, Dong-Joo Moon, Young-Jun Park","doi":"10.1177/16878132241272197","DOIUrl":"https://doi.org/10.1177/16878132241272197","url":null,"abstract":"We develop a program for predicting bearing performance, including the maximum contact stress, bearing power loss, minimum lubricating film thickness, static safety factor, and dynamic life, and an optimal design for high-speed angular contact ball bearings in aircraft gearboxes using optimization algorithms. A program is developed to predict bearing performance by calculating the loads and displacements of individual balls based on the bearing’s kinematic and static equilibrium equations. Next, an optimization program is developed with non-dominated sorting genetic algorithm III (NSGA-III), wherein calculated bearing performance indicators serve as constraints or objective functions. The performance of individuals within the final Pareto front is evaluated using the inter-criteria correlation (CRITIC) and weighted product methods. The optimization performances of NSGA-III and NSGA-II are compared based on their hypervolume indicators. A solution of the kinematic and static equilibrium equations under the load cases and duty cycles of real aircraft gearboxes is obtained, enhancing the prediction accuracy. Furthermore, optimization, including bearing performance metrics rarely considered in previous studies, is performed. Optimal specifications superior to reference bearings employed in aircraft gearboxes are obtained, enhancing all three objective functions or specific objective functions. The optimization performance of NSGA-III is confirmed to surpass that of conventional NSGA-II.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"27 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1177/16878132241272165
Omer Abbaker Ahmed Mohammed, Lingxi Peng, Gomaa Haroun Ali Hamid, Ahmed Mohamed Ishag
The service life and efficiency of proton exchange membrane fuel cells (PEMFCs) are significantly related to the control performance of the air supply system. Therefore, this research develops a novel robust observer-based- [Formula: see text]-variable model-free supertwisting fractional-order sliding mode control ([Formula: see text]-MF-STFOSMC) for complex nonlinear PEMFC air supply system with unmeasurable state variables, model uncertainties, and external disturbance. First, the fifth-order nonlinear PEMFC air supply system model is presented, and the unmeasured state variables are estimated using a nonlinear disturbance observer (NDOB1). Second, the ultra-local model (ULM) algorithm is employed to reconstruct the complex nonlinear PEMFC air supply system, avoiding the need for precise modeling and reducing the controller design difficulty. To estimate and compensate for the uncertain dynamics in the ULM algorithm, another NDOB2 is proposed to realize zero estimation error and finite-time observation. Besides, to achieve optimal control performance with less input chattering, finite-time convergence, and fast response speed, the [Formula: see text]-MF-STFOSMC is designed using super-twisting fractional-order sliding mode control (STFOSMC) algorithm. Furthermore, the stability of [Formula: see text]-MF-STFOSMC via a closed-loop system is verified using the Lyapunov theorem. Finally, the nonlinear PEMFC air supply system model with the proposed controller is realized in MATLAB/Simulink environment, and the simulation results are given to show the superiority and effectiveness of the proposed technique.
{"title":"Robust observer-based-α-variable model-free supertwisting fractional order sliding mode control for nonlinear PEMFC system with uncertainties and disturbance","authors":"Omer Abbaker Ahmed Mohammed, Lingxi Peng, Gomaa Haroun Ali Hamid, Ahmed Mohamed Ishag","doi":"10.1177/16878132241272165","DOIUrl":"https://doi.org/10.1177/16878132241272165","url":null,"abstract":"The service life and efficiency of proton exchange membrane fuel cells (PEMFCs) are significantly related to the control performance of the air supply system. Therefore, this research develops a novel robust observer-based- [Formula: see text]-variable model-free supertwisting fractional-order sliding mode control ([Formula: see text]-MF-STFOSMC) for complex nonlinear PEMFC air supply system with unmeasurable state variables, model uncertainties, and external disturbance. First, the fifth-order nonlinear PEMFC air supply system model is presented, and the unmeasured state variables are estimated using a nonlinear disturbance observer (NDOB1). Second, the ultra-local model (ULM) algorithm is employed to reconstruct the complex nonlinear PEMFC air supply system, avoiding the need for precise modeling and reducing the controller design difficulty. To estimate and compensate for the uncertain dynamics in the ULM algorithm, another NDOB2 is proposed to realize zero estimation error and finite-time observation. Besides, to achieve optimal control performance with less input chattering, finite-time convergence, and fast response speed, the [Formula: see text]-MF-STFOSMC is designed using super-twisting fractional-order sliding mode control (STFOSMC) algorithm. Furthermore, the stability of [Formula: see text]-MF-STFOSMC via a closed-loop system is verified using the Lyapunov theorem. Finally, the nonlinear PEMFC air supply system model with the proposed controller is realized in MATLAB/Simulink environment, and the simulation results are given to show the superiority and effectiveness of the proposed technique.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"44 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1177/16878132241275604
Ayesha Naeem, Zaheer Abbas, Sabeeh Khaliq
Two-layer calendering using non-Newtonian fluids is used frequently in different industries to improve the working and the quality of the products. In this article, two-layer calendering of incompressible non-Newtonian fluids, that is, couple stress fluid and viscoplastic fluid in the upper and lower layer respectively is investigated. For the simplified governing equations, Lubrication approximation theory is applied. By the use of no-slip condition and non-dimensional variables, the exact solution for pressure gradient, pressure, and velocity profiles for both layers of fluid is calculated. The parameters are important from an engineering point of view like roll separating force, power delivered by rollers, torque acting by each roller, and adiabatic temperature are also calculated analytically. Additionally, the results of a couple stress parameter, viscoplastic Casson parameter, and viscosity ratios on all the parameters are also discussed and investigated in detail. Moreover, all the effects investigated are also verified with the literature results of single-layer calendering of non-Newtonian fluids by using large numeric values for the couple stress parameter and viscoplastic Casson parameter.
{"title":"Variable viscosity characteristics of two-layered isothermal calendering phenomena with non-Newtonian fluids","authors":"Ayesha Naeem, Zaheer Abbas, Sabeeh Khaliq","doi":"10.1177/16878132241275604","DOIUrl":"https://doi.org/10.1177/16878132241275604","url":null,"abstract":"Two-layer calendering using non-Newtonian fluids is used frequently in different industries to improve the working and the quality of the products. In this article, two-layer calendering of incompressible non-Newtonian fluids, that is, couple stress fluid and viscoplastic fluid in the upper and lower layer respectively is investigated. For the simplified governing equations, Lubrication approximation theory is applied. By the use of no-slip condition and non-dimensional variables, the exact solution for pressure gradient, pressure, and velocity profiles for both layers of fluid is calculated. The parameters are important from an engineering point of view like roll separating force, power delivered by rollers, torque acting by each roller, and adiabatic temperature are also calculated analytically. Additionally, the results of a couple stress parameter, viscoplastic Casson parameter, and viscosity ratios on all the parameters are also discussed and investigated in detail. Moreover, all the effects investigated are also verified with the literature results of single-layer calendering of non-Newtonian fluids by using large numeric values for the couple stress parameter and viscoplastic Casson parameter.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"27 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Air spring isolator is the crucial component of ship floating raft isolation system. However, due to various factors such as manufacturing errors and installation conditions of air spring isolators, abnormal contacts cannot be avoided in the internal limiters of air spring isolator, resulting in the acoustic short circuit fault. This leads to a significant decrease in isolation effectiveness. To address this issue, experiments on the acoustic short circuit fault of air spring isolators are conducted, and the experimental results are analysed. Then the causes behind the phenomena and results of the acoustic short circuit experiments are further elucidated through finite element simulations and mathematical theory analysis. The research results indicate that the acoustic short circuit of air spring isolators affects the isolation effectiveness. The more severe the acoustic short circuit fault, the greater its impact on the isolation effectiveness, particularly in the low-frequency isolation component. This is because, during the acoustic short circuit of air spring isolators, the rubber part of the internal limiter comes into contact, causing an increase in the stiffness of the air spring support, thereby resulting in an increase in the modal frequency of the isolation device and consequently severely impacting the low-frequency isolation effectiveness.
{"title":"Research on the influence of acoustic short circuit fault of air spring isolator on ship floating raft isolation system","authors":"Shuai Wang, Minyue Lu, Haitao Tan, Shiliang Jiang, Miao Zhang, Wei Liu, Jiachi Yao","doi":"10.1177/16878132241275602","DOIUrl":"https://doi.org/10.1177/16878132241275602","url":null,"abstract":"Air spring isolator is the crucial component of ship floating raft isolation system. However, due to various factors such as manufacturing errors and installation conditions of air spring isolators, abnormal contacts cannot be avoided in the internal limiters of air spring isolator, resulting in the acoustic short circuit fault. This leads to a significant decrease in isolation effectiveness. To address this issue, experiments on the acoustic short circuit fault of air spring isolators are conducted, and the experimental results are analysed. Then the causes behind the phenomena and results of the acoustic short circuit experiments are further elucidated through finite element simulations and mathematical theory analysis. The research results indicate that the acoustic short circuit of air spring isolators affects the isolation effectiveness. The more severe the acoustic short circuit fault, the greater its impact on the isolation effectiveness, particularly in the low-frequency isolation component. This is because, during the acoustic short circuit of air spring isolators, the rubber part of the internal limiter comes into contact, causing an increase in the stiffness of the air spring support, thereby resulting in an increase in the modal frequency of the isolation device and consequently severely impacting the low-frequency isolation effectiveness.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"51 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1177/16878132241273526
Mohamed Arezki Mellal
In complex systems, failure dependencies play a crucial role in determining their overall performance. This paper explores the multi-objective optimization of series-parallel systems with mixed failure dependencies. By optimizing system cost and availability, the study aims to identify the most efficient redundancy and repair strategies. Two optimization algorithms, the non-dominated sorting genetic algorithm II (NSGA-II) and a novel multi-objective algorithm named the multi-objective hoopoe heuristic (MOHH), are utilized alongside constraint handling techniques to produce Pareto fronts. These fronts illustrate the trade-offs between cost and availability. Additionally, a fuzzy decision method is utilized to determine the best compromise solutions from each optimization technique. Comparing the results, NSGA-II consistently outperforms MOHH in providing better compromise solutions across five independent runs. However, MOHH demonstrates a better standard deviation in its performance.
{"title":"Multi-objective optimization of series-parallel system with mixed subsystems failure dependencies using NSGA-II and MOHH","authors":"Mohamed Arezki Mellal","doi":"10.1177/16878132241273526","DOIUrl":"https://doi.org/10.1177/16878132241273526","url":null,"abstract":"In complex systems, failure dependencies play a crucial role in determining their overall performance. This paper explores the multi-objective optimization of series-parallel systems with mixed failure dependencies. By optimizing system cost and availability, the study aims to identify the most efficient redundancy and repair strategies. Two optimization algorithms, the non-dominated sorting genetic algorithm II (NSGA-II) and a novel multi-objective algorithm named the multi-objective hoopoe heuristic (MOHH), are utilized alongside constraint handling techniques to produce Pareto fronts. These fronts illustrate the trade-offs between cost and availability. Additionally, a fuzzy decision method is utilized to determine the best compromise solutions from each optimization technique. Comparing the results, NSGA-II consistently outperforms MOHH in providing better compromise solutions across five independent runs. However, MOHH demonstrates a better standard deviation in its performance.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"3 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-speed running bearings generate a large amount of heat, which has a significant impact on the accuracy of machine tool feeding system. In this paper, by applying the bearing proposed statics and local heat source method, considering the combined surface contact thermal resistance and lubricant viscous temperature characteristics of the influence of the thermal network method to determine the main thermal characteristics of the shaft system parameters, the establishment of the transient thermal equilibrium equations, in the iterative process of the shaft system temperature field and deformation of the coupling; through the solution, the bearing temperature field and the transient change of the thermal parameters of the characteristics of the bearing, analyze the working conditions and structural parameters of the bearing transient thermal characteristics curve; using the finite element method coupled field simulation and test bed test, to verify the theoretical model is reasonable. The influence of working conditions and structural parameters on the transient thermal characteristic curve of the bearing is analyzed. The reasonableness of the theoretical model is verified by using the finite element method coupled field simulation and test bench test. After in-depth analysis: no matter the initial clearance or the change of rotational speed and load, it will lead to the change of thermal equilibrium temperature of the bearings, and will produce heat-induced load. Therefore, by choosing the appropriate clearance, improving the viscosity of lubricant, and enhancing the air convection, the heat generation and thermal deformation can be effectively reduced, which provides an important method to support the optimization of the bearing structure and the design of thermal balance.
{"title":"Thermal characterization of cylindrical roller bearings based on thermal-structural coupling approach","authors":"Chuanmeng Yang, Mengyu Zhu, Ming Qiu, Yishuang Chu, Yanfang Dong, Feifan Chen","doi":"10.1177/16878132241266458","DOIUrl":"https://doi.org/10.1177/16878132241266458","url":null,"abstract":"High-speed running bearings generate a large amount of heat, which has a significant impact on the accuracy of machine tool feeding system. In this paper, by applying the bearing proposed statics and local heat source method, considering the combined surface contact thermal resistance and lubricant viscous temperature characteristics of the influence of the thermal network method to determine the main thermal characteristics of the shaft system parameters, the establishment of the transient thermal equilibrium equations, in the iterative process of the shaft system temperature field and deformation of the coupling; through the solution, the bearing temperature field and the transient change of the thermal parameters of the characteristics of the bearing, analyze the working conditions and structural parameters of the bearing transient thermal characteristics curve; using the finite element method coupled field simulation and test bed test, to verify the theoretical model is reasonable. The influence of working conditions and structural parameters on the transient thermal characteristic curve of the bearing is analyzed. The reasonableness of the theoretical model is verified by using the finite element method coupled field simulation and test bench test. After in-depth analysis: no matter the initial clearance or the change of rotational speed and load, it will lead to the change of thermal equilibrium temperature of the bearings, and will produce heat-induced load. Therefore, by choosing the appropriate clearance, improving the viscosity of lubricant, and enhancing the air convection, the heat generation and thermal deformation can be effectively reduced, which provides an important method to support the optimization of the bearing structure and the design of thermal balance.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"7 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-31DOI: 10.1177/16878132241272170
Syed Tauseef Saeed, Khalid Arif, Mubashir Qayyum
The study of magnetohydrodynamic (MHD) fluids has significant implications across various scientific disciplines, particularly in understanding complex phenomena in astrophysics, engineering, and geophysics. The Casson fluid model stands as a crucial tool for describing non-Newtonian behaviors observed in certain fluid systems. The current work shows an analytical analysis to determine the ramped effect on the fractionalized MHD Casson fluid over an vertical plate. Fractional partial differential equations are used to formulate the problem along with initial and boundary conditions. The governing equations are transformed into the dimensionless form and developed fractional models like Caputo-Fabrizio and Atangana-Baleanu Derivative. We used the Laplace transform technique to find the closed form solution of the dimensionless governing equation analytically. MATHCAD software is being used for numerical computations and the physical attributes of material and fractional parameters are discussed. To analyze their behavior clearly, two-dimensional graphical results are plotted for velocity profile and temperature as well. It has been concluded that the fluid’s velocity are reduced for larger values of the fractional parameter and Prandtl number and is maximum for small values of both parameters.
{"title":"Exact solutions of non-singularized MHD Casson fluid with ramped conditions: A comparative study","authors":"Syed Tauseef Saeed, Khalid Arif, Mubashir Qayyum","doi":"10.1177/16878132241272170","DOIUrl":"https://doi.org/10.1177/16878132241272170","url":null,"abstract":"The study of magnetohydrodynamic (MHD) fluids has significant implications across various scientific disciplines, particularly in understanding complex phenomena in astrophysics, engineering, and geophysics. The Casson fluid model stands as a crucial tool for describing non-Newtonian behaviors observed in certain fluid systems. The current work shows an analytical analysis to determine the ramped effect on the fractionalized MHD Casson fluid over an vertical plate. Fractional partial differential equations are used to formulate the problem along with initial and boundary conditions. The governing equations are transformed into the dimensionless form and developed fractional models like Caputo-Fabrizio and Atangana-Baleanu Derivative. We used the Laplace transform technique to find the closed form solution of the dimensionless governing equation analytically. MATHCAD software is being used for numerical computations and the physical attributes of material and fractional parameters are discussed. To analyze their behavior clearly, two-dimensional graphical results are plotted for velocity profile and temperature as well. It has been concluded that the fluid’s velocity are reduced for larger values of the fractional parameter and Prandtl number and is maximum for small values of both parameters.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"27 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aims to numerically investigate the conjugate heat transfer (CHT) and the changes in the hydraulic and thermal terms of laminar flow (300 ≤ Re ≤ 800) in a 3-D wavy microchannel heat sink (MCHS). The obtained results from different nanofluid flow simulated models will be compared. The numerical simulation approaches used include single-phase, mixture, Eulerian, DPM, and DDPM. The effect of adding 1%, 3%, and 6% concentration of CuO nanoparticles (100 nm) in deionized water as the base fluid is examined on various parameters such as local and axial temperature, heat transfer convective coefficient, friction factor, Nusselt number (Nu), velocity distribution, and thermal and hydraulic boundary layer parameters. The substrate surface, due to its larger area surface and the amplitude of the sinusoidal wave, has a greater impact on the nanofluid flow as a channel bottom conjugate surface compared to others. The results obtained from the different models show close agreement with each other for various cases. For example, at Re = 304, the average Nu and friction factor for pure water are approximately 10.43 and 0.0260, respectively. For water with 0.01 concentration of CuO nanoparticles, Nu is found to be in the range of 10.43–10.78, and the friction factor ranges from 0.260 to 0.290, depending on the approach used for simulation. This shows a 2% increase in Nusselt number compared to a 0.05% increase in the friction factor. Moreover, these values increase by approximately 5.7% and 11.3% on average with an increase in CuO nanoparticle concentration to 0.06. Additionally, the DPM and DDPM models show a 15% difference in the scattering of CuO nanoparticles compared to the Eulerian-Eulerian models. The single-phase model presented in this study yields similar results to the multiphase approaches. Furthermore, the PEC parameter increases by about 1.9% with the addition of CuO nanoparticles at a concentration of 0.06.
{"title":"Comparative study of two-phase flow approaches for modeling conjugate heat transfer in a three-dimensional wavy microchannel-heat sink with CuO-water nanofluid","authors":"Farshid Marzban, Mahshid Marzban, Kazem Mohammadzadeh, Somayeh Davoodabadi Farahani","doi":"10.1177/16878132241273517","DOIUrl":"https://doi.org/10.1177/16878132241273517","url":null,"abstract":"This study aims to numerically investigate the conjugate heat transfer (CHT) and the changes in the hydraulic and thermal terms of laminar flow (300 ≤ Re ≤ 800) in a 3-D wavy microchannel heat sink (MCHS). The obtained results from different nanofluid flow simulated models will be compared. The numerical simulation approaches used include single-phase, mixture, Eulerian, DPM, and DDPM. The effect of adding 1%, 3%, and 6% concentration of CuO nanoparticles (100 nm) in deionized water as the base fluid is examined on various parameters such as local and axial temperature, heat transfer convective coefficient, friction factor, Nusselt number (Nu), velocity distribution, and thermal and hydraulic boundary layer parameters. The substrate surface, due to its larger area surface and the amplitude of the sinusoidal wave, has a greater impact on the nanofluid flow as a channel bottom conjugate surface compared to others. The results obtained from the different models show close agreement with each other for various cases. For example, at Re = 304, the average Nu and friction factor for pure water are approximately 10.43 and 0.0260, respectively. For water with 0.01 concentration of CuO nanoparticles, Nu is found to be in the range of 10.43–10.78, and the friction factor ranges from 0.260 to 0.290, depending on the approach used for simulation. This shows a 2% increase in Nusselt number compared to a 0.05% increase in the friction factor. Moreover, these values increase by approximately 5.7% and 11.3% on average with an increase in CuO nanoparticle concentration to 0.06. Additionally, the DPM and DDPM models show a 15% difference in the scattering of CuO nanoparticles compared to the Eulerian-Eulerian models. The single-phase model presented in this study yields similar results to the multiphase approaches. Furthermore, the PEC parameter increases by about 1.9% with the addition of CuO nanoparticles at a concentration of 0.06.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"39 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bearing faults can cause heavy disruptions in machinery operation, which is why their reliable diagnosis is crucial. While current research into bearing fault analysis focuses on analyzing vibration data under constant working conditions, it is important to consider the challenges that arise when machinery runs at variable speeds, which is usually the case. This article proposes a multistage classifier for diagnosing bearings under time-variable conditions. We validate our method using vibration signals from five bearing health states, including a combined fault case. Our approach involves decomposing the signals using Empirical Wavelet Transform and computing temporal and frequency domain attributes. We use the Expectation-Maximization Gaussian mixture model for optimization concerns to identify relevant parameters and train the Random Forest classifier with the selected features. Our method, evaluated using the Polygon Area Metric, has demonstrated high effectiveness in diagnosing bearings under time-variable conditions. Our approach offers a promising solution that efficiently addresses speed variability and combined fault recognition issues.
{"title":"Multi-fault bearing diagnosis under time-varying conditions using Empirical Wavelet Transform, Gaussian mixture model, and Random Forest classifier","authors":"Moussaoui Imane, Chemseddine Rahmoune, Moahmed Zair, Djamel Benazzouz","doi":"10.1177/16878132241275787","DOIUrl":"https://doi.org/10.1177/16878132241275787","url":null,"abstract":"Bearing faults can cause heavy disruptions in machinery operation, which is why their reliable diagnosis is crucial. While current research into bearing fault analysis focuses on analyzing vibration data under constant working conditions, it is important to consider the challenges that arise when machinery runs at variable speeds, which is usually the case. This article proposes a multistage classifier for diagnosing bearings under time-variable conditions. We validate our method using vibration signals from five bearing health states, including a combined fault case. Our approach involves decomposing the signals using Empirical Wavelet Transform and computing temporal and frequency domain attributes. We use the Expectation-Maximization Gaussian mixture model for optimization concerns to identify relevant parameters and train the Random Forest classifier with the selected features. Our method, evaluated using the Polygon Area Metric, has demonstrated high effectiveness in diagnosing bearings under time-variable conditions. Our approach offers a promising solution that efficiently addresses speed variability and combined fault recognition issues.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"22 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-31DOI: 10.1177/16878132241273529
Ke Li, Jie Ding, Xiaodong Sun, Xuan Meng
Due to the presence of brush and slip ring in the excitation method of electrically excited synchronous motors, this article proposes a new excitation method - non-contact excitation system. This method transfers electrical energy from the stator to the rotor through magnetic coupling, replacing slip ring and brush. However, the magnetic coupling coils at the primary and secondary ends of the system will deviate, which will affect motor operation quality. In order to effectively reduce the changes caused by mutual inductance, this article proposes an improved particle swarm optimization algorithm for mutual inductance identification. This improved algorithm can effectively reduce the shortcomings of low accuracy and easy to fall into local optima in particle swarm optimization. Simulation and experimental results show that the improved particle swarm optimization algorithm can improve search accuracy.
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