Amirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29378120240301Motion Analyses in Modeling of Flow and Contaminant in Cleanrooms: A Review318548010.22060/ajme.2024.22889.6083ENMaysamSaidiDepartment of Mechanical Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran0000-0001-7423-334XJaberEslamiDepartment of Mechanical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20231223The motion effect on the contaminant dispersion is a key parameter in cleanrooms. This parameter is ignored in many experimental and numerical studies because of its complexities but could cause errors in the obtained results. In real situations, particularly in isolating rooms and cleanrooms, the motion that is usually caused by the human moving and doors opening and closing leads to considerable flow changes that require attention. The present study aimed to explore studies that noticed and studied different aspects of the subject and to summarize the areas with priority for further investigation. Modeling the problem using experimental and numerical approaches requires steps and settings that are described in the experimental and numerical sections. The motion analysis is divided into two sections of human and door motions, covering the key findings of previous and recent publications, and concluding the required future studies. The results of approximately fifty published studies have revealed important findings related to cleanroom class degradation, temperature gradient reduction, increased contamination and secondary flow depth, and particle settlement in patients. These studies have shown that the ventilation system may need to be redesigned. Furthermore, it is crucial to consider the motion in both experimental and numerical studies based on the application. Additional research is necessary to further understand these findings.https://ajme.aut.ac.ir/article_5480_c6e81542b125c36346d9167691b8bd09.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29378120240301Modeling the subgrid-scale kinetic energy in a turbulent channel flow using artificial neural network1930547910.22060/ajme.2024.23091.6101ENAminRasamFaculty of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, Iran0000-0002-3173-7502AliNajarianFaculty of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, IranJournal Article20240405Modeling the subgrid-scale energy, , has important applications in large-eddy simulation, including the lattice Boltzmann method and formulation of advanced subgrid-scale models. In this study, a deep neural network is specifically developed to predict for large-eddy simulation of turbulent channel flow. To produce the training data for the neural network, a direct numerical simulation of turbulent channel flow at the friction Reynolds number is performed using an existing highly accurate pseudo-spectral method. The impact of the neural network configuration on its predictions is studied by examining the mean, probability density function and skewness of . Moreover, the correlation with the filtered data, its relative and root mean square error are also examined using <em>a priori </em>analysis. Appreciable improvements in the predictions were observed with increasing the number of neurons in the hidden layer, up to 64. Increasing the number of hidden layers to two and three showed small improvements in the predictions.The performance of the neural network is also compared with a dynamic subgrid-scale model. The comparison reveals that the neural network predictions reach correlation coefficients higher than 90% with the filtered direct numerical simulation data, whereas the dynamic subgrid-scale model predictions only reach up to about 50%. Also, a closer agreement was observed with the filtered data for the neural network predictions of , compared with the dynamic subgrid-scale model.https://ajme.aut.ac.ir/article_5479_ac2460b56866901d732f996b82b69d31.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29378120240301Buckling Analysis of the Composite Sandwich Cylindrical Shell Integrated with Auxetic Metamaterial Core3142548210.22060/ajme.2024.23182.6110ENKoroshKhorshidiDepartment of Mechanical Engineering, Arak University, Arak, Iran0000-0002-7321-972XSaboorSavvafiDepartment of Mechanical Engineering, Arak University, Arak, IranSadeghZobeidDepartment of Mechanical Engineering, Arak University, Arak, IranJournal Article20240512This study investigated the effect of an auxetic structure, positioned as the central layer in a three-layered cylindrical shell, on its buckling behavior. The material for all three layers is aluminum. The covers are assumed isotropic. Axial and static loads are modeled as pressure on the shell's surface. In this study, modified shear deformation theory and Galerkin's numerical solution method were used, and the effect of the presence of an auxetic core on the buckling behavior of a three-layered cylindrical shell was investigated. The assumed structure for the auxetic cell was a 2D Re-entrant honeycomb. Finally, we explore how the length-to-radius ratio, core thickness-to-total thickness ratio, and cell angle of the auxetic structure impact the system's stability, presenting the results. The distinguishing feature of the current work compared to previous studies lies in its mathematical approach. We present the system's equations as comprehensively as possible. Finally, the effect of the length-to-radius ratio, the auxetic layer's thickness relative to the whole shell's thickness, and the cell angle's size on the buckling load were investigated. In short, with the increase of both ratios, the amount of load required for buckling decreases, or in other words, system stability is reduced. Also, the size of the cell angle has little effect on the system's stability.https://ajme.aut.ac.ir/article_5482_f4f691ac947fd92b7ab3c33d3f90bfed.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29378120240301Simplified Freeze Desalination through Enhanced Recovery Rate and Desalination Efficiency4352548310.22060/ajme.2024.22809.6077ENMohammadHendijanifardFaculty of Mechanical Engineering, Shiraz University, Shiraz, Iran0000-0003-1035-8260HabibullahSharifiFaculty of Mechanical Engineering, Shiraz University, Shiraz, IranJournal Article20231115Freeze desalination is an emerging technique since it uses much less energy than most other thermal technologies. As a portion of zero/minimum liquid discharge technologies, crystallization is being commercially used, however, it is probably the most expensive section of the desalination plant. Several freeze desalination techniques are being developed including progressive layer, falling film, suspension freeze, and gas hydrate desalination. The emphasis of most of these methods is to improve the desalination efficiency. Developing a complete freeze desalination plant requires recognizing the critical importance of both recovery rate and desalination efficiency. In a study, a comprehensive freeze desalination plant was designed with a 50% recovery rate and 50% desalination efficiency. To achieve proper salt rejection from 78% of incoming seawater, the plant needs to undergo 46 stages of desalination. The plant is then redesigned with a recovery rate of 90% and a desalination efficiency of 90%. It is shown that in only 6 stages of desalination, 89% of the whole seawater can be desalinated which is a cost reduction of at least 87%.https://ajme.aut.ac.ir/article_5483_d72a7ed33514158ae5e68ed6d80177b9.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29378120240301Tracking Control of Underwater Vehicles Based on Adaptive Nonlinear Robust Inner/Outer Loop Approach5366548410.22060/ajme.2024.22757.6072ENFahimeh S.Tabatabaee-NasabCenter of Excellence in Robotics and Control, Advanced Robotics & Automated Systems (ARAS) Laboratory, Tehran, IranDepartment of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, IranS. Ali AkbarMoosavianCenter of Excellence in Robotics and Control, Advanced Robotics & Automated Systems (ARAS) Laboratory, Tehran, IranDepartment of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran0000-0002-9117-7615Journal Article20231016Highly nonlinear systems with parametric uncertainties and external disturbances deteriorate the tracking control performance of autonomous underwater vehicles. In this research, to attain- optimal precision, an adaptive integral-type terminal sliding mode controller is proposed. To this end, the kinematics and kinetics controller laws are developed as the outer and inner loop control to track desired trajectories. The kinematics controller, as the outer controller, is developed to control the position errors. The kinetics controller, as the inner servo loop, is developed based on the system dynamics model and an adaptive integral-exponential sliding surface to control the internal velocity errors. In order to enhance the control proficiency, we have implemented an adaptive switching rule within the kinetic control algorithm, enabling an automated adjustment of all controller parameters. Therefore, the increase and decrease of these switching parameters will occur according to the system conditions, while its stability is guaranteed using Lyapunov theorems. The obtained results show the merits of the proposed controller in terms of high accuracy performance and low computation cost for real-time implementations.https://ajme.aut.ac.ir/article_5484_03b2ceb73723f8b53cd533e4fba898ee.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-29378120240301Experimental and Image Processing Study on the Effect of the Cavitation Phenomenon in a Nozzle Injector on the Hydrodynamic Behavior of the Spray6782548710.22060/ajme.2024.22847.6080ENSaeidAziziDepartment of Mechanical Engineering, University of Tabriz, Tabriz, IranMohammad TaghiShervani-TabarDepartment of Mechanical Engineering, University of Tabriz, Tabriz, Iran0000-0002-6668-9096Journal Article20231215The hydrodynamic behavior of liquid spray is influenced by the geometry of the injector nozzle, which has a significant impact on the combustion process and quality of fuel atomization. In this survey, transparent and visible nozzles were fabricated from Plexiglas to facilitate experimental visualization of the nozzle interior and enhance the accuracy of liquid spray investigation. To achieve this, three types of nozzles with varying orifice coefficients were prepared. Results showed that at a certain pressure, for a divergent conical nozzle, the intensity of cavitation increases, and it’s very prone to cavitation. Conversely, the convergent conical nozzle suppresses cavitation. As the pressure of fluid injection rises within nozzles, cavitation bubbles persist until reaching the orifice's end, resulting in the super-cavitation phenomenon. Further, increasing injection pressure triggers the hydraulic flip phenomenon. The occurrence of the super-cavitation phenomenon causes uniform droplet distribution of the resulting spray. In other words, The pressure corresponding to the occurrence of the super-cavitation phenomenon has a better droplet breakup and distribution (divergent conical nozzle with an injection pressure of 3 MPa). At a certain injection pressure with decreasing <em>k</em> factor outlet volume flow rate of the nozzle decreases and the spray cone angle increases. Therefore, the desired macroscopic characteristic of the spray could be determined by specifying the <em>k</em> factor.https://ajme.aut.ac.ir/article_5487_139042a4157a773f209847829d80894d.pdf