Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 56 7 2024 09 22 Modeling of thermal gradient effect on reverse osmosis process Modeling of thermal gradient effect on reverse osmosis process 911 930 5583 10.22060/mej.2024.22950.7699 FA Mohsen Zhyianey Bakhsh Mechanical Engineering Department, University of Hormozgan, Bandar Abbas, Iran. Ehsan Abedini Mechanical Engineering Department, University of Hormozgan, Bandar Abbas, Iran. 0000-0003-0082-5937 Saeid Niazi Mechanical Engineering Department, University of Hormozgan, Bandar Abbas, Iran. Younes Bakhshan Mechanical Engineering Department, University of Hormozgan, Bandar Abbas, Iran. Pouyan Adibi Mechanical Engineering Department, University of Hormozgan, Bandar Abbas, Iran. 0000-0003-3815-9968 Journal Article 2024 02 10 In the present study modeling and formulation of the thermal gradient effect on reverse osmosis process for evaluation treated water penetration and water production are studied. Modeling is done by MATLAB using the Solution-Diffusion model. At present work, the effect of two different parameters (temperature difference gradient and salt concentration) on different parameters is studied. Studying important parameters for temperature-driven reverse osmosis shows the direct effect of the temperature difference between the permeate-water part and the saline water part on different parameters. On temperature-driven reverse osmosis, the temperature difference between the permeate-water part and the saline-water part acts as a driving force. The penetration rate at each salt concentration rises by increasing the temperature difference between the permeate-water part and the saline-water part. The variations of different parameters versus temperature differences for two different saline water part concentrations (1 gr/lit and 0.35 gr/lit) are presented. For 1 gr/lit salt concentration and 1.5, 2.5, and 10.8 OC temperature difference between the permeate-water part and saline-water part, treated water penetrations are obtained 0.9, 0.9545, and 1.3118 l/m2.h.bar respectively. Also, for 0.35 gr/lit salt concentration and 1.5 and 9.3 OC temperature difference between the permeate-water part and saline-water part, treated water penetrations are obtained at 0.917 and 1.167 l/m2.h.bar respectively. In the present study modeling and formulation of the thermal gradient effect on reverse osmosis process for evaluation treated water penetration and water production are studied. Modeling is done by MATLAB using the Solution-Diffusion model. At present work, the effect of two different parameters (temperature difference gradient and salt concentration) on different parameters is studied. Studying important parameters for temperature-driven reverse osmosis shows the direct effect of the temperature difference between the permeate-water part and the saline water part on different parameters. On temperature-driven reverse osmosis, the temperature difference between the permeate-water part and the saline-water part acts as a driving force. The penetration rate at each salt concentration rises by increasing the temperature difference between the permeate-water part and the saline-water part. The variations of different parameters versus temperature differences for two different saline water part concentrations (1 gr/lit and 0.35 gr/lit) are presented. For 1 gr/lit salt concentration and 1.5, 2.5, and 10.8 OC temperature difference between the permeate-water part and saline-water part, treated water penetrations are obtained 0.9, 0.9545, and 1.3118 l/m2.h.bar respectively. Also, for 0.35 gr/lit salt concentration and 1.5 and 9.3 OC temperature difference between the permeate-water part and saline-water part, treated water penetrations are obtained at 0.917 and 1.167 l/m2.h.bar respectively.

https://mej.aut.ac.ir/article_5583_43c656628a4a479e108ed86f7a28a010.pdf

Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 56 7 2024 09 22 Application of Gain and Phase Margins for Designing Robust Controllers within Quantitative Feedback Theory Application of Gain and Phase Margins for Designing Robust Controllers within Quantitative Feedback Theory 931 954 5588 10.22060/mej.2024.23255.7736 FA Mohammadreza Hadipour Faculty of Mechanical Engineering, Guilan University, Rasht, Iran Ali Jamali Faculty of Mechanical Engineering, Guilan University, Rasht, Iran Nader Nariman-zadeh Faculty of Mechanical Engineering, Guilan University, Rasht, Iran Behnam Miripour Fard Faculty of Mechanical Engineering, Guilan University, Rasht, Iran Journal Article 2024 06 07 Modeling uncertainty in the form of additional gain and phase and calculating robustness margins based on them is one of the standard methods in designing robust control systems and comparing their robustness. On the other hand, one of the prevalent methods of robust control in the frequency domain is “Quantitative Feedback Theory”, which, due to modeling uncertainty in the form of parametric uncertainty with a specified range, faces challenges such as the inability to compare controllers and non-automated design. Additionally, the system's conditions for parametric uncertainty values outside the design range are unknown. This research addresses these issues using uncertainty modeling in the form of gain and phase within the quantitative feedback theory method. To this end, a combined margin consisting of gain and phase is introduced and calculated using a modified Nichols chart and inequalities related to design criteria in the quantitative feedback theory method. The position control of a DC motor is selected as a case study, and an optimal and robust proportional-derivative controller is designed for it. The results are examined both numerically and experimentally which show that the proposed method effectively overcomes the shortcomings of the quantitative feedback theory method. The controller designed in this manner gains more favorable results than the controller designed using the conventional quantitative feedback theory method and even maintains its performance better for parametric uncertainty values higher than the design range. Modeling uncertainty in the form of additional gain and phase and calculating robustness margins based on them is one of the standard methods in designing robust control systems and comparing their robustness. On the other hand, one of the prevalent methods of robust control in the frequency domain is “Quantitative Feedback Theory”, which, due to modeling uncertainty in the form of parametric uncertainty with a specified range, faces challenges such as the inability to compare controllers and non-automated design. Additionally, the system's conditions for parametric uncertainty values outside the design range are unknown. This research addresses these issues using uncertainty modeling in the form of gain and phase within the quantitative feedback theory method. To this end, a combined margin consisting of gain and phase is introduced and calculated using a modified Nichols chart and inequalities related to design criteria in the quantitative feedback theory method. The position control of a DC motor is selected as a case study, and an optimal and robust proportional-derivative controller is designed for it. The results are examined both numerically and experimentally which show that the proposed method effectively overcomes the shortcomings of the quantitative feedback theory method. The controller designed in this manner gains more favorable results than the controller designed using the conventional quantitative feedback theory method and even maintains its performance better for parametric uncertainty values higher than the design range.

https://mej.aut.ac.ir/article_5588_90415f9b8d0fe2da891b58a2dab18f8d.pdf

Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 56 7 2024 09 22 Exergoeconomic analysis and multi-objective optimization for single, double and triple flash cycles for utilization of booshli’s Geothermal well Exergoeconomic analysis and multi-objective optimization for single, double and triple flash cycles for utilization of booshli’s Geothermal well 955 982 5592 10.22060/mej.2024.23369.7750 FA Mehran Abdolalipouradl Asisstant, Professor Department of Mechanical Engineering, Faculty of Mechanical Engineering, Jundi-Shapur University of Technology, Dezful, Iran Mohamad Namkhah Department of Mechanical Engineering, Faculty of Mechanical Engineering, Jundi-Shapur University of Technology, Dezful, Iran Journal Article 2024 07 22 In recent years increasing the energy demand and limited resources of fossil fuels have led us to develop and pay more attention to renewable energies, especially geothermal energy. Due to recent investigations, it has been realized that Iran has substantial geothermal potential. Booshli in northwestern Iran is one of the regions with the most geothermal potential. In the present study, single, double, and triple flash cycles for producing power from Booshli’s geothermal well have been investigated. Then, the presented cycles have been analyzed from energy, exergy, and economic viewpoints. Furthermore, different single-objective approaches (energy efficiency, exergy efficiency, and power-specific cost) and multi-objective approaches, are optimized relative to their separator's Pressure, respectively. Moreover, a parametric study has been carried out on the separator’s pressure to establish the effect on performance parameters for each cycle. It has been revealed that triple flash has a better performance compared to single and double flash cycles for power production from Booshli's geothermal well, both in thermodynamics and economic aspects. The results show that for a triple flash cycle in multi-objective optimum condition (at pressure 1351 kPa for the first, 440.9 kPa for the second, and 80.09 kPa for the third separator), the net output power, energy efficiency, exergy efficiency, exergoeconomic factor, and the power specific cost rate were calculated to be 8463 kW, 15.24%, 57.01, 79.7% and 4.853 $/GJ, respectively. In recent years increasing the energy demand and limited resources of fossil fuels have led us to develop and pay more attention to renewable energies, especially geothermal energy. Due to recent investigations, it has been realized that Iran has substantial geothermal potential. Booshli in northwestern Iran is one of the regions with the most geothermal potential. In the present study, single, double, and triple flash cycles for producing power from Booshli’s geothermal well have been investigated. Then, the presented cycles have been analyzed from energy, exergy, and economic viewpoints. Furthermore, different single-objective approaches (energy efficiency, exergy efficiency, and power-specific cost) and multi-objective approaches, are optimized relative to their separator's Pressure, respectively. Moreover, a parametric study has been carried out on the separator’s pressure to establish the effect on performance parameters for each cycle. It has been revealed that triple flash has a better performance compared to single and double flash cycles for power production from Booshli's geothermal well, both in thermodynamics and economic aspects. The results show that for a triple flash cycle in multi-objective optimum condition (at pressure 1351 kPa for the first, 440.9 kPa for the second, and 80.09 kPa for the third separator), the net output power, energy efficiency, exergy efficiency, exergoeconomic factor, and the power specific cost rate were calculated to be 8463 kW, 15.24%, 57.01, 79.7% and 4.853 $/GJ, respectively.

https://mej.aut.ac.ir/article_5592_94f4ede62112b790c91d5e64fdb09cb8.pdf

Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 56 7 2024 09 22 Coordinated Control of Multiple Agents for Automatic Landing and Execution of Formation Flights using Fuzzy Control Allocation Approach Coordinated Control of Multiple Agents for Automatic Landing and Execution of Formation Flights using Fuzzy Control Allocation Approach 983 1002 5600 10.22060/mej.2024.23297.7739 FA Saba Nikseresht K. N. Toosi University of Technology Mahdi Jafari Nadoushan Department of Space Engineering, Faculty of Aerospace Engineering, K. N. Toosi University of Technology. 0000-0001-8493-8175 Journal Article 2024 06 23 In many next-generation platforms, the application of control allocation approaches is one of the most effective methods for performing coordinated aerial maneuvers. This approach minimizes the energy required for various operations, compensates for actuator faults, enhances reliability and dependability, and prevents actuator saturation. This paper addresses the coordinated control of multiple agents for autonomous landing and coordinated maneuvers using a fuzzy control allocation approach. In this framework, one of the platforms assumes the role of a leader agent, while the other two operate as follower agents. By employing a fuzzy controller, optimizing its parameters with a genetic algorithm, and allocating control signals among lift actuators and the thrust vector control system, agents can be guided with desired stability, sufficient accuracy, and minimal control effort to a specific altitude, followed by executing well-organized and synchronized maneuvers. The results demonstrate that the fuzzy control allocation method achieves high precision in controlling the landing of platforms to a designated altitude. Ultimately, the platforms execute coordinated autonomous landing maneuvers with favorable conditions, sufficient stability, high accuracy, relatively short execution time, and minimal control effort. In many next-generation platforms, the application of control allocation approaches is one of the most effective methods for performing coordinated aerial maneuvers. This approach minimizes the energy required for various operations, compensates for actuator faults, enhances reliability and dependability, and prevents actuator saturation. This paper addresses the coordinated control of multiple agents for autonomous landing and coordinated maneuvers using a fuzzy control allocation approach. In this framework, one of the platforms assumes the role of a leader agent, while the other two operate as follower agents. By employing a fuzzy controller, optimizing its parameters with a genetic algorithm, and allocating control signals among lift actuators and the thrust vector control system, agents can be guided with desired stability, sufficient accuracy, and minimal control effort to a specific altitude, followed by executing well-organized and synchronized maneuvers. The results demonstrate that the fuzzy control allocation method achieves high precision in controlling the landing of platforms to a designated altitude. Ultimately, the platforms execute coordinated autonomous landing maneuvers with favorable conditions, sufficient stability, high accuracy, relatively short execution time, and minimal control effort.

https://mej.aut.ac.ir/article_5600_7ea4e7fcdc6aff2777bd594a3754e02a.pdf

Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 56 7 2024 09 22 Miniaturization of combustion gas transmission equipment using traveling wave rotary piezoelectric actuator with the approach of improving safety and functional characteristics Miniaturization of combustion gas transmission equipment using traveling wave rotary piezoelectric actuator with the approach of improving safety and functional characteristics 1003 1026 5606 10.22060/mej.2024.23321.7743 FA Ebrahim Abolghasemi Ph.D. Student,, Malek Ashtar University Ahmad Reza Khoogar Department of Mechanical Engineering, Maleke-Ashtar University of Technology, Lavizan, Tehran, Iran Mehrdad Khandaei Faculty, Malek-Ashtar university of technology Journal Article 2024 07 02 The space and weight limitation in air systems has always created the need to improve characteristics such as dimensions, weight, accuracy, and safety in the equipment used in these systems. This research uses the advantages of piezoelectric actuators, such as miniaturization, self-locking, working in harsh conditions, high safety, etc., to propose their use as actuators in combustion gas transmission equipment. A traveling-wave rotary piezoelectric actuator was selected, and a gas valve was installed in it. In the numerical section, the actuator was analyzed by the finite element, and frequency sensitivity analysis was performed. Then a prototype is made in the optimal state. In the experimental section, the prototype parameters were evaluated and validated with the numerical results. In the results section, the efficiency of the piezoelectric actuator as a separate actuator was proven by measuring the output speed and torque. By comparing the geometrical parameters, it was shown that the combustion gas transmission was able to reduce 28%, 57%, and 50% in diameter, volume, and weight, respectively. By conducting environmental tests, it was found that this equipment can prevent changes in the gas valve status in harsh environmental conditions caused by vibrations and temperature changes and provide a high safety factor. The space and weight limitation in air systems has always created the need to improve characteristics such as dimensions, weight, accuracy, and safety in the equipment used in these systems. This research uses the advantages of piezoelectric actuators, such as miniaturization, self-locking, working in harsh conditions, high safety, etc., to propose their use as actuators in combustion gas transmission equipment. A traveling-wave rotary piezoelectric actuator was selected, and a gas valve was installed in it. In the numerical section, the actuator was analyzed by the finite element, and frequency sensitivity analysis was performed. Then a prototype is made in the optimal state. In the experimental section, the prototype parameters were evaluated and validated with the numerical results. In the results section, the efficiency of the piezoelectric actuator as a separate actuator was proven by measuring the output speed and torque. By comparing the geometrical parameters, it was shown that the combustion gas transmission was able to reduce 28%, 57%, and 50% in diameter, volume, and weight, respectively. By conducting environmental tests, it was found that this equipment can prevent changes in the gas valve status in harsh environmental conditions caused by vibrations and temperature changes and provide a high safety factor.

https://mej.aut.ac.ir/article_5606_e6385d39ec9394f2f3a354d9d2b88eec.pdf

Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 56 7 2024 09 22 Numerical Simulation of Heat Flux Evaluation for Atmospheric Re-entry Control Wing Connections Numerical Simulation of Heat Flux Evaluation for Atmospheric Re-entry Control Wing Connections 1027 1050 5607 10.22060/mej.2024.23096.7718 FA Mostafa Mahmoodi malek ashtar university 0009-0000-1754-3966 Hamid Parhizkar malek ashtar university Jamasb Pirkandi malek ashtar university Journal Article 2024 04 09 The present research has investigated the simulation of the aerodynamic heating of a missile with regard to the placement and non-placement of the control block and its connection components. In this research, a commercialized missile in four different configurations was investigated (missile without the placement of other components, missile with the placement of a control block, missile with the placement of a control block with a shaft attached to it, and missile with the placement of a control block with a shaft attached to it and considering the wedge) and the results have been compared between different configurations. The results showed that the presence of a control block as an obstacle in the way of airflow has increased the heat flux on the missile surface by about 27% compared to the first phase. In the upstream of the shaft, this increase in the amount of heat flux is 5 times compared to the case without the shaft. Also, with the simulation of the fourth phase, the effect of the presence of the wedge in guiding the fluid flow and reducing the damaging effects of heating around the location of the shaft was revealed. The results showed that the presence of the wedge caused the heat flux of the missile surface to decrease by about 52% compared to the third phase. Also, the wedge has reduced the maximum heat flux created on the shaft surface by about 74% compared to the third phase. The present research has investigated the simulation of the aerodynamic heating of a missile with regard to the placement and non-placement of the control block and its connection components. In this research, a commercialized missile in four different configurations was investigated (missile without the placement of other components, missile with the placement of a control block, missile with the placement of a control block with a shaft attached to it, and missile with the placement of a control block with a shaft attached to it and considering the wedge) and the results have been compared between different configurations. The results showed that the presence of a control block as an obstacle in the way of airflow has increased the heat flux on the missile surface by about 27% compared to the first phase. In the upstream of the shaft, this increase in the amount of heat flux is 5 times compared to the case without the shaft. Also, with the simulation of the fourth phase, the effect of the presence of the wedge in guiding the fluid flow and reducing the damaging effects of heating around the location of the shaft was revealed. The results showed that the presence of the wedge caused the heat flux of the missile surface to decrease by about 52% compared to the third phase. Also, the wedge has reduced the maximum heat flux created on the shaft surface by about 74% compared to the third phase.

https://mej.aut.ac.ir/article_5607_96bf57c6ff19504ff145e2a32991ea96.pdf