Amirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-6032571220260220Design and Numerical Simulation of a Magnetophoretic System with a Rotating-Field for Manipulation and Separation of Magnetic MicroparticlesDesign and Numerical Simulation of a Magnetophoretic System with a Rotating-Field for Manipulation and Separation of Magnetic Microparticles15371550606710.22060/mej.2026.25348.7943FAAtabakMohammadi MoazedEnergy Conversion Department, Faculty of, Mechanical Engineering, Tarbiat Modares UniversityRoozbehAbedini-NassabEnergy Conversion Department,, Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran0000-0002-0729-7770Journal Article20251226In this study, a novel system based on magnetophoretic chips has been designed and simulated for the manipulation and controlled size-based separation of magnetic microparticles within a microfluidic environment. The system consists of magnetic nanofilms in the form of interconnected disks with a separation gap and a rotating magnetic field generated by permanent magnets. The magnetic field generator setup, using a stepper motor and an Arduino controller, enables adjustment of the rotation frequency. Three-dimensional modeling was carried out using SolidWorks, and the distribution of the magnetic energy on the chip was simulated using COMSOL Multiphysics. Additionally, particle trajectories and magnetic forces were analyzed through custom-developed MATLAB codes. The simulation results, for validation purposes, were compared with experimental data from previous studies, and the good agreement of the particle trajectories (with an average radial error of 2.61%) demonstrated the high accuracy of the simulations. Then, using this validated model, the performance of the designed system in particle separation was evaluated, and it was found that by selecting gaps of 2 to 7 micrometers, under magnetic field strengths of 50 and 100 Oersted and by adjusting the frequency, micrometric particles with different sizes could be separated. By eliminating challenges associated with coil circuits and undesired heating in previous methods, this study provides a reliable, simple, and efficient solution with biological and medical applications.In this study, a novel system based on magnetophoretic chips has been designed and simulated for the manipulation and controlled size-based separation of magnetic microparticles within a microfluidic environment. The system consists of magnetic nanofilms in the form of interconnected disks with a separation gap and a rotating magnetic field generated by permanent magnets. The magnetic field generator setup, using a stepper motor and an Arduino controller, enables adjustment of the rotation frequency. Three-dimensional modeling was carried out using SolidWorks, and the distribution of the magnetic energy on the chip was simulated using COMSOL Multiphysics. Additionally, particle trajectories and magnetic forces were analyzed through custom-developed MATLAB codes. The simulation results, for validation purposes, were compared with experimental data from previous studies, and the good agreement of the particle trajectories (with an average radial error of 2.61%) demonstrated the high accuracy of the simulations. Then, using this validated model, the performance of the designed system in particle separation was evaluated, and it was found that by selecting gaps of 2 to 7 micrometers, under magnetic field strengths of 50 and 100 Oersted and by adjusting the frequency, micrometric particles with different sizes could be separated. By eliminating challenges associated with coil circuits and undesired heating in previous methods, this study provides a reliable, simple, and efficient solution with biological and medical applications.https://mej.aut.ac.ir/article_6067_024d2d699e6c1a82c9ba986386f4d824.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-6032571220260220Numerical investigation of natural convection heat transfer enhancement in a tall rectangular enclosure by three rotating cylindersNumerical investigation of natural convection heat transfer enhancement in a tall rectangular enclosure by three rotating cylinders15511572609610.22060/mej.2026.25135.7923FAHesamMoayediFaculty of Chemical and Industrial Engineering, University of Science and Technology of Mazandaran, Behshahr, Iran0000-0002-8320-5292Journal Article20251119This study numerically investigates the effects of different arrangements of three rotating cylinders inside a tall rectangular enclosure on the flow pattern and enhancement of natural convection heat transfer. The two-dimensional, steady, single-phase flow and energy equations were solved using the finite volume method. The impact of parameters such as cylinder configurations (1 to 5), angular velocities (from -5 to +5), and relative rotation directions on the flow pattern, power required to rotate the cylinders, and heat transfer rate enhancement inside the enclosure was evaluated. Results were compared with a cylinder-free enclosure under various conditions. The presence of three cylinders, whether stationary or rotating, altered the natural convection flow pattern by splitting the primary vortex into multiple vortices of varying sizes. Counterclockwise rotation of the cylinders resulted in a greater increase in the Nusselt number compared to clockwise rotation. The greatest Nusselt number enhancement, about 47.6%, occurred in the configuration 1 at an angular velocity of -5 when all cylinders rotated synchronously. Additionally, independent rotation of cylinders with angular velocities ω=+5, ω=+5, and ω=-5 in configuration 1, increased the average Nusselt number by approximately 66%.This study numerically investigates the effects of different arrangements of three rotating cylinders inside a tall rectangular enclosure on the flow pattern and enhancement of natural convection heat transfer. The two-dimensional, steady, single-phase flow and energy equations were solved using the finite volume method. The impact of parameters such as cylinder configurations (1 to 5), angular velocities (from -5 to +5), and relative rotation directions on the flow pattern, power required to rotate the cylinders, and heat transfer rate enhancement inside the enclosure was evaluated. Results were compared with a cylinder-free enclosure under various conditions. The presence of three cylinders, whether stationary or rotating, altered the natural convection flow pattern by splitting the primary vortex into multiple vortices of varying sizes. Counterclockwise rotation of the cylinders resulted in a greater increase in the Nusselt number compared to clockwise rotation. The greatest Nusselt number enhancement, about 47.6%, occurred in the configuration 1 at an angular velocity of -5 when all cylinders rotated synchronously. Additionally, independent rotation of cylinders with angular velocities ω=+5, ω=+5, and ω=-5 in configuration 1, increased the average Nusselt number by approximately 66%.https://mej.aut.ac.ir/article_6096_e7dfca01f394755c11f853602cb2608a.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-6032571220260220Development of an Operational Framework for Smart Management and Energy Flexibility in Net-Zero Energy BuildingsDevelopment of an Operational Framework for Smart Management and Energy Flexibility in Net-Zero Energy Buildings15731600610310.22060/mej.2026.25615.7956FAMojtabaMasoumnezhadDepartment of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran.0000-0002-3395-8886Journal Article20260305The transition toward Net-Zero Energy Buildings (NZEBs) necessitates the integration of energy flexibility with smart management systems. However, a literature review reveals a significant gap between theoretical flexibility frameworks and their operational feasibility in real-world contexts, particularly concerning cybersecurity challenges and stakeholder interest conflicts. To bridge this gap, the present study develops an integrated conceptual-operational framework grounded in the philosophical foundations of Critical Realism. This framework is structured into a five-layer architecture (physical, digital, optimization, grid, and policy). For its operationalization, the IDADA method and novel composite indicators, including the Composite Flexibility Index (CFI), the Stakeholder Benefit Index (SBI), and privacy-related metrics, are utilized. For validation, a 10-unit residential complex in a hot and dry climate was simulated using the Design Builder/Energy Plus environment, and the indicators were weighted through a hybrid AHP-Delphi approach.<br><br>The results demonstrate that implementing this framework leads to an 85.7% improvement in the CFI and a 134% surge in the SBI (balancing the interests of residents and the grid). Furthermore, sensitivity analysis via the Monte Carlo method confirmed the high robustness of the model against behavioral and economic uncertainties with a 95% confidence interval. This framework provides a novel pathway for policymakers and engineers to institutionalize grid-interactive buildings.The transition toward Net-Zero Energy Buildings (NZEBs) necessitates the integration of energy flexibility with smart management systems. However, a literature review reveals a significant gap between theoretical flexibility frameworks and their operational feasibility in real-world contexts, particularly concerning cybersecurity challenges and stakeholder interest conflicts. To bridge this gap, the present study develops an integrated conceptual-operational framework grounded in the philosophical foundations of Critical Realism. This framework is structured into a five-layer architecture (physical, digital, optimization, grid, and policy). For its operationalization, the IDADA method and novel composite indicators, including the Composite Flexibility Index (CFI), the Stakeholder Benefit Index (SBI), and privacy-related metrics, are utilized. For validation, a 10-unit residential complex in a hot and dry climate was simulated using the Design Builder/Energy Plus environment, and the indicators were weighted through a hybrid AHP-Delphi approach.<br><br>The results demonstrate that implementing this framework leads to an 85.7% improvement in the CFI and a 134% surge in the SBI (balancing the interests of residents and the grid). Furthermore, sensitivity analysis via the Monte Carlo method confirmed the high robustness of the model against behavioral and economic uncertainties with a 95% confidence interval. This framework provides a novel pathway for policymakers and engineers to institutionalize grid-interactive buildings.https://mej.aut.ac.ir/article_6103_56880339cfb8fe04c2d17c6160d0512f.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-6032571220260220Influence of Blade Outlet Angle on the Inverse Design Method for Centrifugal Pump ImpellersInfluence of Blade Outlet Angle on the Inverse Design Method for Centrifugal Pump Impellers16011618610410.22060/mej.2026.25139.7924FAAbdollahEskandariPayame Noor University - Faculty of Engineering0000-0003-4441-6473Journal Article20251120This research explores the impact of blade outlet angle on the inverse design methodology of centrifugal pump impellers, aiming to enhance hydraulic performance through improved flow control and reduced secondary losses. The inverse design approach is employed to regulate blade loading and achieve a more uniform pressure distribution at the impeller outlet, thereby optimizing efficiency and head generation. Blade geometries were generated using vorticity-based modeling combined with inviscid slip boundary conditions to minimize tangential pressure gradients and suppress secondary flow structures. Three outlet angles—0°, +45°, and –45°—were imposed as boundary conditions in the design process. The resulting impeller configurations were evaluated using computational fluid dynamics (CFD) simulations and validated against experimental data. The results demonstrate that a negative outlet angle (–45°) significantly improves flow uniformity, reduces tangential pressure gradients, and weakens secondary vortices, leading to a hydraulic efficiency increase of up to 8.5% and a head rise of approximately 3.2 meters at the design operating point. These findings highlight the critical role of outlet angle selection in inverse blade design and its potential to improve turbomachinery performance. The study provides a robust framework for integrating geometric optimization into pump design strategies, offering practical insights for engineers seeking to enhance energy efficiency and operational reliability in fluid transport systems.This research explores the impact of blade outlet angle on the inverse design methodology of centrifugal pump impellers, aiming to enhance hydraulic performance through improved flow control and reduced secondary losses. The inverse design approach is employed to regulate blade loading and achieve a more uniform pressure distribution at the impeller outlet, thereby optimizing efficiency and head generation. Blade geometries were generated using vorticity-based modeling combined with inviscid slip boundary conditions to minimize tangential pressure gradients and suppress secondary flow structures. Three outlet angles—0°, +45°, and –45°—were imposed as boundary conditions in the design process. The resulting impeller configurations were evaluated using computational fluid dynamics (CFD) simulations and validated against experimental data. The results demonstrate that a negative outlet angle (–45°) significantly improves flow uniformity, reduces tangential pressure gradients, and weakens secondary vortices, leading to a hydraulic efficiency increase of up to 8.5% and a head rise of approximately 3.2 meters at the design operating point. These findings highlight the critical role of outlet angle selection in inverse blade design and its potential to improve turbomachinery performance. The study provides a robust framework for integrating geometric optimization into pump design strategies, offering practical insights for engineers seeking to enhance energy efficiency and operational reliability in fluid transport systems.https://mej.aut.ac.ir/article_6104_46384036044a604b6b3316fc167fc15f.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-6032571220260220Evaluation of Surface Integrity of AISI 304 in Electrochemical Grinding through Simultaneous Analysis of Surface Roughness and PorosityEvaluation of Surface Integrity of AISI 304 in Electrochemical Grinding through Simultaneous Analysis of Surface Roughness and Porosity16191636610910.22060/mej.2026.25003.7926FAArminRezaeiDepartment of Mechanical engineering , trabiat modares universityAmirRASTIDepartment of mechanical enginering, Tarbiat modules university0000-0002-0138-6764MohammadYazdanitarbiat modares universityJournal Article20251126The electrochemical grinding (ECG) process, as a hybrid technique combining mechanical abrasion and anodic dissolution, offers an efficient approach for improving surface quality and minimizing thermal damage in hard-to-machine steels, particularly AISI 304 stainless steel. However, the surface roughness and porosity in this process are strongly affected by operating conditions, exhibiting inherently nonlinear behavior. In this study, a dedicated experimental setup was designed and developed to investigate the effects of three key parameters: electrolyte concentration (20–180 g/L), applied voltage (5–25 V), and wheel rotational speed (500–2500 rpm). Surface roughness was measured using a laser profilometer, while porosity was quantified through image analysis in ImageJ software. Results indicated that increasing electrolyte concentration gradually reduced surface roughness from approximately 15 to 4 μm, while porosity increased from 1.2% to over 5%. Moreover, voltage variation exhibited a nonlinear trend, and an optimal balance between roughness and porosity was achieved within the range of 10–15 V. Higher voltages led to excessive corrosion and loss of surface uniformity. Increasing wheel speed up to around 1500 rpm also resulted in a moderate improvement in surface finish. Overall, the combination of 180 g/L electrolyte concentration and 15 V applied voltage was identified as the optimal condition for producing a smooth surface with controlled porosity.The electrochemical grinding (ECG) process, as a hybrid technique combining mechanical abrasion and anodic dissolution, offers an efficient approach for improving surface quality and minimizing thermal damage in hard-to-machine steels, particularly AISI 304 stainless steel. However, the surface roughness and porosity in this process are strongly affected by operating conditions, exhibiting inherently nonlinear behavior. In this study, a dedicated experimental setup was designed and developed to investigate the effects of three key parameters: electrolyte concentration (20–180 g/L), applied voltage (5–25 V), and wheel rotational speed (500–2500 rpm). Surface roughness was measured using a laser profilometer, while porosity was quantified through image analysis in ImageJ software. Results indicated that increasing electrolyte concentration gradually reduced surface roughness from approximately 15 to 4 μm, while porosity increased from 1.2% to over 5%. Moreover, voltage variation exhibited a nonlinear trend, and an optimal balance between roughness and porosity was achieved within the range of 10–15 V. Higher voltages led to excessive corrosion and loss of surface uniformity. Increasing wheel speed up to around 1500 rpm also resulted in a moderate improvement in surface finish. Overall, the combination of 180 g/L electrolyte concentration and 15 V applied voltage was identified as the optimal condition for producing a smooth surface with controlled porosity.https://mej.aut.ac.ir/article_6109_27b09e189a405b6cca6ddd7ec869c143.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-6032571220260220An Intelligent Two-Layer Controller Based on Hysteresis and PID Logic for Performance Improvement of a Direct-Expansion Solar Heat PumpAn Intelligent Two-Layer Controller Based on Hysteresis and PID Logic for Performance Improvement of a Direct-Expansion Solar Heat Pump16371656612410.22060/mej.2026.25760.7967FAAbouzarTaghizadehDepartment of Electrical Engineering, Technical and Vocational University (TVU), Tehran, Iran0000-0003-3383-3861VahidRezaeeDepartment of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran0000-0002-3395-8886EhsanAbdollahzadehDepartment of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, IranJournal Article20260430This study proposes an innovative framework for designing a two-layer intelligent controller for direct expansion solar heat pump systems. The system consists of a flat-plate solar collector–evaporator with a surface area of 3.1 m², a variable-frequency hermetic rotary compressor, a hot-water storage tank with a volume of 0.1 m³, a finned-tube condenser, and a capillary tube (expansion valve). The first layer, based on hysteresis logic, utilizes DS18B20 digital temperature sensors and an Arduino microcontroller to perform basic control and energy management under normal operating conditions. This layer was designed and evaluated experimentally. The second layer comprises a PID controller whose parameters are tuned according to the system’s ARX model using the direct synthesis method. This controller activates under severe disturbances, such as sudden variations in solar irradiance or inlet temperature, restoring the system’s control accuracy to its optimal level. Quantitative results obtained from experimental implementation under three scenarios—steady-state, step disturbance, and periodic disturbance—demonstrate that the proposed controller, in comparison with the standalone hysteresis controller, reduces the RMS temperature error under steady-state conditions from 0.95°C to 0.28°C (a 70.5% reduction), and decreases the number of compressor on/off cycles from 42 to 35 (a 16.6% reduction). Furthermore, energy consumption under disturbance scenarios is reduced by 24.4% and 19.6%, respectively, compared to the standalone hysteresis controller.This study proposes an innovative framework for designing a two-layer intelligent controller for direct expansion solar heat pump systems. The system consists of a flat-plate solar collector–evaporator with a surface area of 3.1 m², a variable-frequency hermetic rotary compressor, a hot-water storage tank with a volume of 0.1 m³, a finned-tube condenser, and a capillary tube (expansion valve). The first layer, based on hysteresis logic, utilizes DS18B20 digital temperature sensors and an Arduino microcontroller to perform basic control and energy management under normal operating conditions. This layer was designed and evaluated experimentally. The second layer comprises a PID controller whose parameters are tuned according to the system’s ARX model using the direct synthesis method. This controller activates under severe disturbances, such as sudden variations in solar irradiance or inlet temperature, restoring the system’s control accuracy to its optimal level. Quantitative results obtained from experimental implementation under three scenarios—steady-state, step disturbance, and periodic disturbance—demonstrate that the proposed controller, in comparison with the standalone hysteresis controller, reduces the RMS temperature error under steady-state conditions from 0.95°C to 0.28°C (a 70.5% reduction), and decreases the number of compressor on/off cycles from 42 to 35 (a 16.6% reduction). Furthermore, energy consumption under disturbance scenarios is reduced by 24.4% and 19.6%, respectively, compared to the standalone hysteresis controller.https://mej.aut.ac.ir/article_6124_b16e8712b35e498857df08af3944b127.pdf