Shahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Experimental and numerical study on the effects of friction and specimen dimension in split Hopkinson pressure barExperimental and numerical study on the effects of friction and specimen dimension in split Hopkinson pressure bar111263910.22044/jsfm.2022.11488.3519FASeyed Mohamad ErfanMossaviSchool of mechanical Engineering,
Iran University of Science and TechnologyMohammad JavadAshrafiSchool of Mechanical Engineering, Iran University of Science and Technology, Tehran.SaeedMirshafieeSchool of mechanical Engineering,
Iran University of Science and TechnologyJournal Article14001018Split Hopkinson pressure bar apparatus (SHPB) is used commonly for determining high strain rate material properties. The validity of the SHPB test results depend on many parameters. In this paper, the effect of specimen dimension (aspect ratio) as well as friction on test results is studied both numerically and experimentally. ABAQUS/Explicit is used for numerical study. To this end, the signals at strain gage positions (on input and out bars) are extracted and stress-strain curve of the specimen is determined using wave propagation analysis. By comparing these stress-strain curves for different states of friction and specimen dimensions, the validity of the experimental and numerical results are checked. By increasing friction, the stress increase and strain decrease in the output stress-strain curve and the best result is for no friction condition. Its is observed that by increasing the aspect ratio, the discrepancy of the results for different friction conditions decreases. Specifically, in simulation results, the difference between maximum stresses of with and without lubrication for aspect ratios 0.25, 0.5, 1.0 and 1.5 are 58%, 18%, 9% and 5%, respectively which is in agreement with experimental trends. In other words, different stress-strain curves are obtained for different aspect ratios in the presence of friction which is mainly due to the friction effect rather than strain rate effect. As the friction increases, the error will reduce the overall strain of the sample and increase the yield stress.Split Hopkinson pressure bar apparatus (SHPB) is used commonly for determining high strain rate material properties. The validity of the SHPB test results depend on many parameters. In this paper, the effect of specimen dimension (aspect ratio) as well as friction on test results is studied both numerically and experimentally. ABAQUS/Explicit is used for numerical study. To this end, the signals at strain gage positions (on input and out bars) are extracted and stress-strain curve of the specimen is determined using wave propagation analysis. By comparing these stress-strain curves for different states of friction and specimen dimensions, the validity of the experimental and numerical results are checked. By increasing friction, the stress increase and strain decrease in the output stress-strain curve and the best result is for no friction condition. Its is observed that by increasing the aspect ratio, the discrepancy of the results for different friction conditions decreases. Specifically, in simulation results, the difference between maximum stresses of with and without lubrication for aspect ratios 0.25, 0.5, 1.0 and 1.5 are 58%, 18%, 9% and 5%, respectively which is in agreement with experimental trends. In other words, different stress-strain curves are obtained for different aspect ratios in the presence of friction which is mainly due to the friction effect rather than strain rate effect. As the friction increases, the error will reduce the overall strain of the sample and increase the yield stress.https://jsfm.shahroodut.ac.ir/article_2639_0fe4ae77d0349912529de5edf4772027.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Kinematic and inverse kinematic analysis of hybrid Delta parallel robot with spherical wrist using Adptive Neuro Fuzzy Inference SystemKinematic and inverse kinematic analysis of hybrid Delta parallel robot with spherical wrist using Adptive Neuro Fuzzy Inference System1330264810.22044/jsfm.2022.11141.3457FAAidinZardstShahrood University of TechnologyHabibAhmadiMahnazSharifniaShahrood University of TechnologyJournal Article14000604In this research, direct kinematic and inverse kinematic analysis of a 6 DOF hybrid robot has been performed by connecting a spherical parallel robot with three degrees of rotational freedom to a delta parallel robot. The advantage of this combination is that the motion equations are independent of the spatial orientation equations so that the robot can be moved to any location from the Delta robot workspace without any limitations, with any orientation that is available through a spherical parallel robot. Therefore, the kinematic models of these two parallel robots are extracted independently and ultimately combined to work as an integrated platform. A mechanical model of the robot is implemented in Simscape environment of MATLAB software. Then, the accuracy of these two models is checked and shown to be perfectly consistent. The transational and rotational workspace for the end-effector of the hybrid parallel robot have also been calculated using robot kinematic relations and by the help of numerical methods. Additionally, the robot inverse kinematics has been used to implement an adaptive neuro fuzzy inference system (ANFIS) to predict kinematic responses with high accuracy.In this research, direct kinematic and inverse kinematic analysis of a 6 DOF hybrid robot has been performed by connecting a spherical parallel robot with three degrees of rotational freedom to a delta parallel robot. The advantage of this combination is that the motion equations are independent of the spatial orientation equations so that the robot can be moved to any location from the Delta robot workspace without any limitations, with any orientation that is available through a spherical parallel robot. Therefore, the kinematic models of these two parallel robots are extracted independently and ultimately combined to work as an integrated platform. A mechanical model of the robot is implemented in Simscape environment of MATLAB software. Then, the accuracy of these two models is checked and shown to be perfectly consistent. The transational and rotational workspace for the end-effector of the hybrid parallel robot have also been calculated using robot kinematic relations and by the help of numerical methods. Additionally, the robot inverse kinematics has been used to implement an adaptive neuro fuzzy inference system (ANFIS) to predict kinematic responses with high accuracy.https://jsfm.shahroodut.ac.ir/article_2648_a2d8ee371dedca8716c0da993d42e0ab.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Fusion of inertial measurement system and visual navigation for unmanned aerial vehicles using Hardware in the Loop simulationFusion of inertial measurement system and visual navigation for unmanned aerial vehicles using Hardware in the Loop simulation3146264710.22044/jsfm.2022.11229.3472FAMasoudAlizadehSharif University of TechnologyAbdolmajidKhoshnoodK.N. Toosi university of technologyJournal Article14000720The main purpose of this paper is presentation a novel approach of inertial-vision based navigation to increase accuracy and safety factor simultaneously. In order to estimate navigation parameters, consist of velocity, position and orientation (attitude) the Extended Kalman Filter (EKF) is used. In proposed method, the Inertial Measurment Unit (includes of 3-axis accelerometer and gyrospope) and vision data considered as navigation process model and measurement model respectively. By utilizing the Scale Invariant Feature Transform (SIFT) method, means transform the image data in to scale invariant coordinates relative to local feature, the 2D position of UAV is obtained. The real time Hardware in the Loop (HIL) simulation technique is used To evaluate overall system performance and efficiency such as serial interface time delay, appropriate operating frequency selection and micro-controller performance at implemented image processing and data fusion algorithm. The real time HIL simulation results clearly show despite of low frequency in vison based navigation, proposed approach has acceptable accuracy for estimating uav navigation paraqmeters. Maintaining accuracy and cost, the proposed approach can be a suitable alternative method to drones that use GPS-based navigation.The main purpose of this paper is presentation a novel approach of inertial-vision based navigation to increase accuracy and safety factor simultaneously. In order to estimate navigation parameters, consist of velocity, position and orientation (attitude) the Extended Kalman Filter (EKF) is used. In proposed method, the Inertial Measurment Unit (includes of 3-axis accelerometer and gyrospope) and vision data considered as navigation process model and measurement model respectively. By utilizing the Scale Invariant Feature Transform (SIFT) method, means transform the image data in to scale invariant coordinates relative to local feature, the 2D position of UAV is obtained. The real time Hardware in the Loop (HIL) simulation technique is used To evaluate overall system performance and efficiency such as serial interface time delay, appropriate operating frequency selection and micro-controller performance at implemented image processing and data fusion algorithm. The real time HIL simulation results clearly show despite of low frequency in vison based navigation, proposed approach has acceptable accuracy for estimating uav navigation paraqmeters. Maintaining accuracy and cost, the proposed approach can be a suitable alternative method to drones that use GPS-based navigation.https://jsfm.shahroodut.ac.ir/article_2647_4c2d3296399dc27f3f750146ddd37337.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Numerical investigation of the effect of an elastic wall on Heat Transfer around a cylinder within a channelNumerical investigation of the effect of an elastic wall on Heat Transfer around a cylinder within a channel4758265210.22044/jsfm.2022.11303.3485FAHOJJATDANANDEH OSKUEIIran-Tabriz-Tabriz University-Faculty of MechanicsSeyed EsmailRazaviIran-Tabriz-Tabriz University-Faculty of MechanicsSeyed FaramarzRanjbarIran-Tabriz-Tabriz University-Faculty of MechanicsJournal Article14000801The fluid-solid interaction of forced convective flow around a circular cylinder within a channel is investigated. All the channel surfaces are insulated, and the cylinder has heat transfer with the cold passing flow at a constant temperature. The lower surface of the channel is rigid, while the upper part is elastic. Crossing the flow into the hot surface and vibrating the elastic shell cause the heat transfer rate of the cylinder to change. The changes depend on the vibration conditions of the elastic oscillator. It was found that the location of the elastic surface, vibrational amplitude and frequency are the most significant factors affecting the exit flow temperature of the channel. The variation of main parameters (elastic surface location, amplitude and frequency) which affect the flow pattern was investigated. Studies at five different Reynolds shows that replacing the elastic wall on the cylinder upstream has a more significant effect on increasing heat transfer compared to the cylinder downstream. The results also indicate a growth in average Nusselt number by rising the vibrational amplitude and frequency.The fluid-solid interaction of forced convective flow around a circular cylinder within a channel is investigated. All the channel surfaces are insulated, and the cylinder has heat transfer with the cold passing flow at a constant temperature. The lower surface of the channel is rigid, while the upper part is elastic. Crossing the flow into the hot surface and vibrating the elastic shell cause the heat transfer rate of the cylinder to change. The changes depend on the vibration conditions of the elastic oscillator. It was found that the location of the elastic surface, vibrational amplitude and frequency are the most significant factors affecting the exit flow temperature of the channel. The variation of main parameters (elastic surface location, amplitude and frequency) which affect the flow pattern was investigated. Studies at five different Reynolds shows that replacing the elastic wall on the cylinder upstream has a more significant effect on increasing heat transfer compared to the cylinder downstream. The results also indicate a growth in average Nusselt number by rising the vibrational amplitude and frequency.https://jsfm.shahroodut.ac.ir/article_2652_2661a8defc8bbc05b8a9a7a8f09803ab.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Free Vibration Analysis of Piezoelectric Nanobeam Based on a 2ِِD- Formulation and Non-local Elasticity TheoryFree Vibration Analysis of Piezoelectric Nanobeam Based on a 2ِِD- Formulation and Non-local Elasticity Theory5972264410.22044/jsfm.2022.11286.3482FAMahsaNajafiDepartment of Mechanical Engineering, University of Zanjan, Zanjan, IranIsaAhmadiUniversity of ZanjanJournal Article14000725The present paper presents an accurate and efficient method for the analysis of free vibration of piezoelectric nanobeam. In this method, Eringen's nonlocal elasticity theory is used to apply the small-scale effects. Despite the shear deformation theories, in the present theory, the displacement and strain fields are considered as a general form, and out-of-plane normal strain is not neglected. The governing equations of piezoelectric nanobeam are derived by employing Hamilton's principle. By solving these equations, natural frequencies related to flexural and thickness modes for the free vibration of nanobeam are obtained. The Convergence of the predicted results is studied, and the effects of various parameters such as nonlocal parameter, length to thickness ratio, and applied external voltage are investigated. To verify the accuracy of the present method, the results predicted by the present theory are compared with those of the theories available in the literature and the finite element method. This study shows that the natural frequencies predicted by the present theory are smaller than those of shear deformation theories. The results of this study show that the natural frequency of the piezoelectric nanobeam increases by increasing the negative applied electric voltage as well as tensile axial load and decreasing the nonlocal parameter. The results show that the natural frequencies related to thickness modes are not negligible and the shear deformation theories, the present theory can predict these frequencies.The present paper presents an accurate and efficient method for the analysis of free vibration of piezoelectric nanobeam. In this method, Eringen's nonlocal elasticity theory is used to apply the small-scale effects. Despite the shear deformation theories, in the present theory, the displacement and strain fields are considered as a general form, and out-of-plane normal strain is not neglected. The governing equations of piezoelectric nanobeam are derived by employing Hamilton's principle. By solving these equations, natural frequencies related to flexural and thickness modes for the free vibration of nanobeam are obtained. The Convergence of the predicted results is studied, and the effects of various parameters such as nonlocal parameter, length to thickness ratio, and applied external voltage are investigated. To verify the accuracy of the present method, the results predicted by the present theory are compared with those of the theories available in the literature and the finite element method. This study shows that the natural frequencies predicted by the present theory are smaller than those of shear deformation theories. The results of this study show that the natural frequency of the piezoelectric nanobeam increases by increasing the negative applied electric voltage as well as tensile axial load and decreasing the nonlocal parameter. The results show that the natural frequencies related to thickness modes are not negligible and the shear deformation theories, the present theory can predict these frequencies.https://jsfm.shahroodut.ac.ir/article_2644_e66565480a8e5ac7750694bf801a1ca5.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Investigating the effects of geometric and environmental parameters on the governing equations of scanning earth horizon sensor and attitude determination error analysisInvestigating the effects of geometric and environmental parameters on the governing equations of scanning earth horizon sensor and attitude determination error analysis7391264210.22044/jsfm.2022.11309.3487FAFatemehHeiranSolid Mechanics Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, IranBehroozRaeisyInstitute of Mechanics, Iranian Space Research Center, Shiraz, IranRaminVatankhahSolid Mechanics Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, IranSajjadTaghvaeiSolid Mechanics Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, IranJournal Article14000727This study is performed to estimate the error of solving governing equations of a dual-cone scanning earth horizon sensor in presence of geometric and environmental parameters. In the process of extracting the equations for determining the sensor’s attitude, firstly, a simplified form of the earth as an sphere without atmosphere is used to model the earth and compared with the governed attitude of simulated satellite on a hypothetical orbit. But in reality, the geometric factor of the earth oblateness and environmental factors such as the sensor's field of view, the effect of the atmosphere and its reflection from the earth's surface cause errors in attitude determination of the satellite. Therefore, by assuming that the sensor is mounted on a satellite, simulating motion in a near earth orbit and modeling the sensor, the sensor’s inlet pulse and the amount of roll and pitch angles in different geometric and environmental conditions are calculated. Then, by comparing the calculated attitude with the simplified case, the effect of each in the occurrence of error are obtained. The simulation is based on a dual-cone scanning earth horizon sensor made in the Institute of Mechanics of Iranian Space Research Center on MicroMAS satellite. According to the simulation results, the atmosphere radiation and surface reflection, earth oblateness and sensor FOV in roll angle and in pitch angle, earth oblateness, atmosphere radiation and surface reflection and sensor FOV are the most effective factor in revealing error respectively.This study is performed to estimate the error of solving governing equations of a dual-cone scanning earth horizon sensor in presence of geometric and environmental parameters. In the process of extracting the equations for determining the sensor’s attitude, firstly, a simplified form of the earth as an sphere without atmosphere is used to model the earth and compared with the governed attitude of simulated satellite on a hypothetical orbit. But in reality, the geometric factor of the earth oblateness and environmental factors such as the sensor's field of view, the effect of the atmosphere and its reflection from the earth's surface cause errors in attitude determination of the satellite. Therefore, by assuming that the sensor is mounted on a satellite, simulating motion in a near earth orbit and modeling the sensor, the sensor’s inlet pulse and the amount of roll and pitch angles in different geometric and environmental conditions are calculated. Then, by comparing the calculated attitude with the simplified case, the effect of each in the occurrence of error are obtained. The simulation is based on a dual-cone scanning earth horizon sensor made in the Institute of Mechanics of Iranian Space Research Center on MicroMAS satellite. According to the simulation results, the atmosphere radiation and surface reflection, earth oblateness and sensor FOV in roll angle and in pitch angle, earth oblateness, atmosphere radiation and surface reflection and sensor FOV are the most effective factor in revealing error respectively.https://jsfm.shahroodut.ac.ir/article_2642_a714617555d0d6e8e88016e93ce210dc.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Investigation on the effect of laser cladding parameters of Inconel 713 LC by Metco 81VF powder on the microstructure characteristics and micro hardness of coatingInvestigation on the effect of laser cladding parameters of Inconel 713 LC by Metco 81VF powder on the microstructure characteristics and micro hardness of coating93108263410.22044/jsfm.2022.11993.3609FAMahmoudFasahatDepartment of mechanical engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.HamidSoleimanimehrAssist. Prof., Department of mechanical engineering, Science and Research Branch, Islamic Azad University, Tehran, IranAliAlinia-ziaziDepartment of mechanical engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.Journal Article14010418In this paper, laser cladding of Inconel 713 LC was performed by using Metco 81VF powder and 400 W pulsed Nd:YAG laser. The effect of laser parameters including laser frequency, pulse width, and laser scanning speed was investigated on the microstructure characteristics and microhardness of coating. The results showed that by increasing the laser frequency and pulse width or decreasing the laser scanning speed, the heat input increases and therefore, the resultant dilution ratio raises. The clad zone of the samples with a high dilution ratio consists of a eutectic structure (γ and Cr7C3). However, the clad zone of specimens with a low dilution ratio is composed of a hypereutectic structure of Cr7C3+(γ+Cr7C3). Increasing the laser frequency and pulse width (increasing the dilution ratio and removal of primary carbides in the microstructure) causes the decrease in microhardnes of the clad zone, but increasing the laser scanning speed has an opposite effect and causes the increases in microhardness of the clad zone. The optimal sample was selected with a laser frequency of 18.4 Hz, a pulse width of 11.2 ms and a laser scanning speed of 2.8 mm/s. This sample, in addition to the acceptable dilution ratio and appearance, has a remarkable hardness of 1204 Vickers, which is about 3 times the hardness of the base metal.In this paper, laser cladding of Inconel 713 LC was performed by using Metco 81VF powder and 400 W pulsed Nd:YAG laser. The effect of laser parameters including laser frequency, pulse width, and laser scanning speed was investigated on the microstructure characteristics and microhardness of coating. The results showed that by increasing the laser frequency and pulse width or decreasing the laser scanning speed, the heat input increases and therefore, the resultant dilution ratio raises. The clad zone of the samples with a high dilution ratio consists of a eutectic structure (γ and Cr7C3). However, the clad zone of specimens with a low dilution ratio is composed of a hypereutectic structure of Cr7C3+(γ+Cr7C3). Increasing the laser frequency and pulse width (increasing the dilution ratio and removal of primary carbides in the microstructure) causes the decrease in microhardnes of the clad zone, but increasing the laser scanning speed has an opposite effect and causes the increases in microhardness of the clad zone. The optimal sample was selected with a laser frequency of 18.4 Hz, a pulse width of 11.2 ms and a laser scanning speed of 2.8 mm/s. This sample, in addition to the acceptable dilution ratio and appearance, has a remarkable hardness of 1204 Vickers, which is about 3 times the hardness of the base metal.https://jsfm.shahroodut.ac.ir/article_2634_fc41eaa1846310922951bbdf0935d51c.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Simulation and Optimizations of Truck’s Cabin Structure Exposed to ExplosionSimulation and Optimizations of Truck’s Cabin Structure Exposed to Explosion109122263510.22044/jsfm.2022.11916.3593FAAliYousefiMSc, Faculty of Automotive Engineering, Iran University of Science and Technology, Tehran, IranFarhadKiaPh.D. candidate, Mechanical Engineering, Islamic Azad University South Tehran Branch, Tehran, IranSeyyed AskariMahdaviPh.D, candidate, Instructor, Mechanical Engineering Department/ Engineering Facility/ Imam Ali Officers' University/Tehran/ IranJournal Article14010223One of the casualties in war zones is casualties due to the explosion of explosives near vehicles. The important issue in these vehicles isn’t to seriously injure the occupant during the explosion. It is necessary to optimize of the cabin structure of heavy vehicles to achieve high-performance vehicles. In this article, the 3-d model of the truck is created to study the effect of exploding near and under a truck and to optimize the truck cabin. The model is meshed by square and 10 mm^2 elements. Then, explosion tests are simulated in two situation: explosion under the vehicle and explosion near the truck according to AEP-55. In the explosion test under the car,using 4 kg TNT equivalent on the ground surface and In the test near the truck, using 8 kg TNT equivalent at the distance of 3 meter at the same level by under cabin surface and the amount of occupant injuries are checked. For meeting the requirements of the explosion and because this truck platform is a commercial vehicle, vehicle floor panels’ material and thickness are modified. The thickness of important parts include 1. Side floor panel 2. Middle floor panel 3. Front side panel 4. Front Panel 5 Door Panel are optimized in 16 modes and Only 7 modes meet the requirements of the explosion test under the vehicle. The optimal mode is 571.39 kg which has decreased 79.72 kg compared to the first mode meet AEP-55 requirements and has decreased 3.31kg compared to the initial mode.One of the casualties in war zones is casualties due to the explosion of explosives near vehicles. The important issue in these vehicles isn’t to seriously injure the occupant during the explosion. It is necessary to optimize of the cabin structure of heavy vehicles to achieve high-performance vehicles. In this article, the 3-d model of the truck is created to study the effect of exploding near and under a truck and to optimize the truck cabin. The model is meshed by square and 10 mm^2 elements. Then, explosion tests are simulated in two situation: explosion under the vehicle and explosion near the truck according to AEP-55. In the explosion test under the car,using 4 kg TNT equivalent on the ground surface and In the test near the truck, using 8 kg TNT equivalent at the distance of 3 meter at the same level by under cabin surface and the amount of occupant injuries are checked. For meeting the requirements of the explosion and because this truck platform is a commercial vehicle, vehicle floor panels’ material and thickness are modified. The thickness of important parts include 1. Side floor panel 2. Middle floor panel 3. Front side panel 4. Front Panel 5 Door Panel are optimized in 16 modes and Only 7 modes meet the requirements of the explosion test under the vehicle. The optimal mode is 571.39 kg which has decreased 79.72 kg compared to the first mode meet AEP-55 requirements and has decreased 3.31kg compared to the initial mode.https://jsfm.shahroodut.ac.ir/article_2635_49399fb02019ed07c068d9aa85d4dd39.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Experimental comparison of microstructure and surface properties of Al / Al2O3 sample produced by powder metallurgy and spark plasma sintering methodsExperimental comparison of microstructure and surface properties of Al / Al2O3 sample produced by powder metallurgy and spark plasma sintering methods123132263710.22044/jsfm.2022.11821.3580FASayyed Mohammad RezaSedehiBirjand University of Iran , Birjand , IranMohammadKhosraviBirjand University of Iran , Birjand , IranYadollahYaghoubi NejadBirjand University of Iran, Birjand, IranJournal Article14010224Due to the high importance of manufacturing methods with metal powders such as aluminum, in this study, using pure aluminum powder, samples were made by two methods of powder metallurgy and spark plasma sintering, and then the samples in terms of microstructure, hardness. Abrasion resistance and corrosion resistance were evaluated. Spark plasma sintering method compared to powder metallurgy method shows significant improvement in hardness, microstructure density, increased wear resistance, and corrosion of aluminum. This improvement can be attributed to the high speed and temperature of the sintering process as well as the simultaneous application of force and temperature, resulting in a more complete density of the structure. The coefficient of wear and hardness increased from 0.9 and 43 Brinell in powder metallurgy method to 0.8 and 49.3 Brinell in spark plasma sintering method, respectively. Also, according to the results of corrosion test, the linear corrosion resistance of sintering-plasma-spark sample is higher than powder metallurgy sample.Due to the high importance of manufacturing methods with metal powders such as aluminum, in this study, using pure aluminum powder, samples were made by two methods of powder metallurgy and spark plasma sintering, and then the samples in terms of microstructure, hardness. Abrasion resistance and corrosion resistance were evaluated. Spark plasma sintering method compared to powder metallurgy method shows significant improvement in hardness, microstructure density, increased wear resistance, and corrosion of aluminum. This improvement can be attributed to the high speed and temperature of the sintering process as well as the simultaneous application of force and temperature, resulting in a more complete density of the structure. The coefficient of wear and hardness increased from 0.9 and 43 Brinell in powder metallurgy method to 0.8 and 49.3 Brinell in spark plasma sintering method, respectively. Also, according to the results of corrosion test, the linear corrosion resistance of sintering-plasma-spark sample is higher than powder metallurgy sample.https://jsfm.shahroodut.ac.ir/article_2637_008206940eb3ff62281f20fb6432de86.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Vibration Analysis of Circular Nanoplates under Nonlinear Electrostatic Excitation Considering the Surface Energy and Size EffectsVibration Analysis of Circular Nanoplates under Nonlinear Electrostatic Excitation Considering the Surface Energy and Size Effects133146263810.22044/jsfm.2022.11601.3538FAMehrdadSheikhlouDepartment of Engineering Sciences, Faculty of Advanced Technologies, University of Mohaghegh Ardabili, Ardabil, IranSeyed AliDelbariDepartment of Engineering Sciences, Faculty of Advanced Technologies, University of of Mohaghegh Ardabili, Ardabil, Iran.AbbasSabahi NaminiDepartment of Engineering Sciences, Faculty of Advanced Technologies, University of of Mohaghegh Ardabili, Ardabil, Iran.ArashAbdolmalekiDepartment of Bio Information, Faculty of Advanced Technologies, University of Mohaghegh Ardabili, Ardabil, Iran.Journal Article14001110This article investigates the primary resonant behavior and static pull-in instability of a circular nanoplate under nonlinear electrostatic actuation. The consistent couple stress theory, Gurtin-Murdoch surface elasticity theory and Hamilton principle were utilized to derive the governing differential equation of transverse vibration Kirchhoff nanoplate by considering the fluid damping and Casimir forces. The governing equation were solved for small amplitude vibrations. To this end, it is assumed that the elastic nanoplate is deflected using a DC bias voltage and then driven to vibrate around its deflected position by a harmonic AC load. The weighted residual method of Galerkin was used to obtain a reduced order model. The method of multiple scales is used to solve the nonlinear equation of motion and, the primary resonance mode frequency response equation is derived. The obtained numerical results were compared to those of previous research works, and a good agreement observed between them. The numerical results revealed that electrostatic actuation and Casmier force have softening effects; but the surface energy can has hardening or softening effect depending on the surface mechanical properties, dimensions and boundary condtions of the nanoplate.This article investigates the primary resonant behavior and static pull-in instability of a circular nanoplate under nonlinear electrostatic actuation. The consistent couple stress theory, Gurtin-Murdoch surface elasticity theory and Hamilton principle were utilized to derive the governing differential equation of transverse vibration Kirchhoff nanoplate by considering the fluid damping and Casimir forces. The governing equation were solved for small amplitude vibrations. To this end, it is assumed that the elastic nanoplate is deflected using a DC bias voltage and then driven to vibrate around its deflected position by a harmonic AC load. The weighted residual method of Galerkin was used to obtain a reduced order model. The method of multiple scales is used to solve the nonlinear equation of motion and, the primary resonance mode frequency response equation is derived. The obtained numerical results were compared to those of previous research works, and a good agreement observed between them. The numerical results revealed that electrostatic actuation and Casmier force have softening effects; but the surface energy can has hardening or softening effect depending on the surface mechanical properties, dimensions and boundary condtions of the nanoplate.https://jsfm.shahroodut.ac.ir/article_2638_a8496f4d74e16a11fc24d56b59a55b6a.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Effect of Tip Injection on Tip Leakage Flow Structure in Axial CompressorEffect of Tip Injection on Tip Leakage Flow Structure in Axial Compressor147160264110.22044/jsfm.2022.11399.3505FASarallahAbbasiarak university of technologyMohammadReeszadehSharif universityShahabEsmaeel Zadeh ValiArak university of technologyJournal Article14000822Tip Leakage flow of the compressor blade is one of the effective factors in performance of axial compressors, which can also damage the compressor blades. In this paper, the effect of air jet injection to reduce the destructive effects of tip leakage flow on the performance of the axial compressor is investigated. For this purpose, the numerical analysis of the flow in the NASA rotor 37 axial compressor is performed using CFX software. Initially, the compressor performance curve in the without injection mode was compared with the experimental results and a good agreement was observed. Then, considering the injection of air for one passage the performance curves of the compressor in comparison with the non-injection mode were examined. By injecting air, the pressure ratio increases and the adiabatic efficiency of the compressor decreases at the same mass flow rates. It was found that air injection reduces the drops in the axial compressor and weakens the created vortices. This reduces the rotor drop coefficient and also reduces the angle of attack. Accordingly, injection increases the stall margin and increases the operating range of the compressor by 6% and 66%, respectively. Also, the tip leakage flow has less power than in the without injection condition, which results in less drop.Tip Leakage flow of the compressor blade is one of the effective factors in performance of axial compressors, which can also damage the compressor blades. In this paper, the effect of air jet injection to reduce the destructive effects of tip leakage flow on the performance of the axial compressor is investigated. For this purpose, the numerical analysis of the flow in the NASA rotor 37 axial compressor is performed using CFX software. Initially, the compressor performance curve in the without injection mode was compared with the experimental results and a good agreement was observed. Then, considering the injection of air for one passage the performance curves of the compressor in comparison with the non-injection mode were examined. By injecting air, the pressure ratio increases and the adiabatic efficiency of the compressor decreases at the same mass flow rates. It was found that air injection reduces the drops in the axial compressor and weakens the created vortices. This reduces the rotor drop coefficient and also reduces the angle of attack. Accordingly, injection increases the stall margin and increases the operating range of the compressor by 6% and 66%, respectively. Also, the tip leakage flow has less power than in the without injection condition, which results in less drop.https://jsfm.shahroodut.ac.ir/article_2641_e5d8a3a0abd7a1829c5b30800c1e6d4d.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Theoretical and Experimental Behavior Analysis of Continuous Soft Robots Consisting of Fiber-Reinforced ActuatorsTheoretical and Experimental Behavior Analysis of Continuous Soft Robots Consisting of Fiber-Reinforced Actuators161173263310.22044/jsfm.2022.12033.3620FASadeghPourghasemi HanzaMechanical Engineering Department/ Amirkabir University of TechnologyHamedGhafariradMechanical Engineering Department/ Amirkabir University of TechnologyJournal Article14010505In this paper, quasi-static analysis of a continuous soft robot made up of three fiber-reinforced actuators is performed. For this purpose, the kinematic and dynamic equations of this robot are extracted and numerically solved by considering it as a Cosserat rod. The resultant equations are dependent on the length of the rod's curvature, and thus can only simulate forces and strains in the longitudinal direction. Due to the difficulties of applying radial forces in this model, the modeling of a single fiber-reinforced actuator using nonlinear elasticity equations is then presented. Finally, by solving these equations, the strains resulting from radial stresses are calculated and integrated with the strains obtained from Cosseart rod model. Experiments have been carried out to validate the proposed theory. For this purpose, the robot end effector position is extracted using image processing methods and compared with the presented models. The experimental results show that applying the effect of radial pressures to the Cosserat model improves the relative error by 13.48%.In this paper, quasi-static analysis of a continuous soft robot made up of three fiber-reinforced actuators is performed. For this purpose, the kinematic and dynamic equations of this robot are extracted and numerically solved by considering it as a Cosserat rod. The resultant equations are dependent on the length of the rod's curvature, and thus can only simulate forces and strains in the longitudinal direction. Due to the difficulties of applying radial forces in this model, the modeling of a single fiber-reinforced actuator using nonlinear elasticity equations is then presented. Finally, by solving these equations, the strains resulting from radial stresses are calculated and integrated with the strains obtained from Cosseart rod model. Experiments have been carried out to validate the proposed theory. For this purpose, the robot end effector position is extracted using image processing methods and compared with the presented models. The experimental results show that applying the effect of radial pressures to the Cosserat model improves the relative error by 13.48%.https://jsfm.shahroodut.ac.ir/article_2633_a9fedf46fbd8fa6b117a1e6840ffe1e3.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Experimental and numerical analysis of the effect of using two perforated plates in front of the target against ballistic impactExperimental and numerical analysis of the effect of using two perforated plates in front of the target against ballistic impact175187263610.22044/jsfm.2022.11826.3581FAJavadNikzareFaculty of Mechanical Engineering Tarbiat Modares University Tehran IranGholamhoseinLiaghatFaculty member of Tarbiat Modares UniversityHamedAhmadiAssistant Professor of Mechanical Engineering, Tarbiat Modares UniversityJournal Article14010208The use of perforated plates as part of an armored plate set to protect people and equipment in front of the target plate has long been considered by researchers. For this purpose, the use of one perforated plate in front of the target plate has been considered so far and it has been found that using a perforated plate in a set of armored plates has several advantages. But this plate set will not be able to provide 100% ballistic protection. For this reason, the idea of using two perforated plates in front of the base plate has been proposed and in this research, the consequences of this kind of arrangement have been analyzed by performing experimental and numerical studies. Observations show that the use of two perforated plates in front of the base plate, although it increases their thickness and weight, at the same time, it improves the ballistic protection of the set of armored plates against the incoming projectile, especially in the weaknesses of using one perforated plate in front of the base plate. By comparing deformations obtained experimental experiments and numerical simulations performed using LS-DYNA software, a good convergence between the results has been observed.The use of perforated plates as part of an armored plate set to protect people and equipment in front of the target plate has long been considered by researchers. For this purpose, the use of one perforated plate in front of the target plate has been considered so far and it has been found that using a perforated plate in a set of armored plates has several advantages. But this plate set will not be able to provide 100% ballistic protection. For this reason, the idea of using two perforated plates in front of the base plate has been proposed and in this research, the consequences of this kind of arrangement have been analyzed by performing experimental and numerical studies. Observations show that the use of two perforated plates in front of the base plate, although it increases their thickness and weight, at the same time, it improves the ballistic protection of the set of armored plates against the incoming projectile, especially in the weaknesses of using one perforated plate in front of the base plate. By comparing deformations obtained experimental experiments and numerical simulations performed using LS-DYNA software, a good convergence between the results has been observed.https://jsfm.shahroodut.ac.ir/article_2636_f76f85a5394a4ee7116acd39d387848c.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Thermodynamic and Exergoeconomic modeling of a modified Organic Rankine Cycle (ORC) augmented with heat exchanger Provided by geothermal
sourceThermodynamic and Exergoeconomic modeling of a modified Organic Rankine Cycle (ORC) augmented with heat exchanger Provided by geothermal
source189200264510.22044/jsfm.2022.11273.3480FARezaBabaei EspooeiPh.D., Mech. Eng., Tarbiat Modares Univ., Tehran, Iran0000-0001-5885-981XJournal Article14000716In the present study, the effect of a heat exchanger on the performance of Combined Rankin Organic Cycle (ORC) and geothermal was investigated. The hot water r coming out of the ground enters a liquid-vapor separator. The generated steam enters the steam turbine section and the liquid section enters a heat exchanger to superheat the refrigerant and rotate the ORC turbine Energy, exergy and exerco-economic modeling was performed using EES software and SPECO method in a wide range of different working fluids. The results showed that the output power of the system has a maximum point in terms of separator pressure for a simple cycle, but increases ascending for the modified cycle without limitation. In terms of energy analysis, modified cycle with heat exchanger compared to the simple cycle, R237ea and n-Pentane have the highest amounts of increasing at the efficiency and power generation are maximum with 45.4 and 40%, respectively. In terms of power generation cost savings, R237ea and R123 with 0.63 and 0.55 (cent / kW-hr), respectively. Cis-2-butene with 6376 kW in terms of power generation and R237ea in terms of cost savings in power generation are the best refrigerants.In the present study, the effect of a heat exchanger on the performance of Combined Rankin Organic Cycle (ORC) and geothermal was investigated. The hot water r coming out of the ground enters a liquid-vapor separator. The generated steam enters the steam turbine section and the liquid section enters a heat exchanger to superheat the refrigerant and rotate the ORC turbine Energy, exergy and exerco-economic modeling was performed using EES software and SPECO method in a wide range of different working fluids. The results showed that the output power of the system has a maximum point in terms of separator pressure for a simple cycle, but increases ascending for the modified cycle without limitation. In terms of energy analysis, modified cycle with heat exchanger compared to the simple cycle, R237ea and n-Pentane have the highest amounts of increasing at the efficiency and power generation are maximum with 45.4 and 40%, respectively. In terms of power generation cost savings, R237ea and R123 with 0.63 and 0.55 (cent / kW-hr), respectively. Cis-2-butene with 6376 kW in terms of power generation and R237ea in terms of cost savings in power generation are the best refrigerants.https://jsfm.shahroodut.ac.ir/article_2645_09e0ca169c80b734f417a255dc307e51.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Energy, Exergy, Economic and Environmental Analysis (4E) of an Organic Rankine Cycle to produce power, hydrogen and desalinated water by combining geothermal energy and heat recoveryEnergy, Exergy, Economic and Environmental Analysis (4E) of an Organic Rankine Cycle to produce power, hydrogen and desalinated water by combining geothermal energy and heat recovery201214264610.22044/jsfm.2023.11259.3477FAMohammad AliSabbaghiMechanical Engineering Department, Yazd University, Yazd, IranMohammadSefidyazd universityJournal Article14000708The usage of multi-generation systems is quickly developing in recent years. The present study analyzes the energy, exergy, economic and environmental (4E) of a novel Rankine organic cycle to produce power, hydrogen and fresh water with a combined energy source of geothermal and heat recovery. Also, the cycle performance in both modes with and without geothermal energy is compared. Calculations show that the highest percent of exergy destruction is equal to 35% and is related to the PEM Also, the lowest amount of exergoeconomic factor is calculated for the PEM is equal to 8.39 The amount of hydrogen and desalinated water produced is 1.64 lit/s and 4.36 kg/s, respectively. With increasing the temperature of the geothermal source from 125 to 155°C, the amount of hydrogen and desalinated water produced are 29 and 17 percentage increases, respectively. If geothermal energy is not used and all energy is supplied by heat recovery, the amount of carbon dioxide emitted will increase to 69%.The usage of multi-generation systems is quickly developing in recent years. The present study analyzes the energy, exergy, economic and environmental (4E) of a novel Rankine organic cycle to produce power, hydrogen and fresh water with a combined energy source of geothermal and heat recovery. Also, the cycle performance in both modes with and without geothermal energy is compared. Calculations show that the highest percent of exergy destruction is equal to 35% and is related to the PEM Also, the lowest amount of exergoeconomic factor is calculated for the PEM is equal to 8.39 The amount of hydrogen and desalinated water produced is 1.64 lit/s and 4.36 kg/s, respectively. With increasing the temperature of the geothermal source from 125 to 155°C, the amount of hydrogen and desalinated water produced are 29 and 17 percentage increases, respectively. If geothermal energy is not used and all energy is supplied by heat recovery, the amount of carbon dioxide emitted will increase to 69%.https://jsfm.shahroodut.ac.ir/article_2646_0a052b530db87d0f5a61277eb000eec6.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Improvement aerodynamic performance of a wind turbine using injecting air jet and Taguchi optimization.Improvement aerodynamic performance of a wind turbine using injecting air jet and Taguchi optimization.215235265010.22044/jsfm.2021.10688.3367FAMortezaMohammadiDepartment of Mechanical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, IranMohammad JawadMaghrebifaculty of engineering, ferdowsi university on mashhadJournal Article14000117Improvement of flow separation around the horizontal axis of the sixth phase wind turbine was investigated by installing air jets. Using Taguchi method and using control parameters, the optimal combinations, and the level of importance of the parameters in increasing torque production were obtained by analyzing the signal-to-noise ratio and variance, and the torques were optimized. It was found that the importance of the parameters on increasing the torque includes the ratio of speed, chord position and longitudinal position, respectively .So a turbine consisting of twelve jets with a width of 0.04 local chord was simulated and numerically solved in the chord positions of 0.1-0.3-0.5 and 0.7 with Fluent software 18.2 and kω-SST turbulence model. Longitudinal places consist of three parts: outer, middle and inner. The velocity ratios for the output jet are 0.2, 1.2, 2.2, 2.8 and 3.2. The results showed that torque changes are dependent on changes in dimensionless parameters such as jet velocity ratio, chord position and longitudinal position. The aerodynamic effects of double, triple and quadruple jets were compared with single jets and the increase in torque was observed due to the improvement of the flow pattern due to the reconnection of the current separated from the blade surface, especially at the blade tip. Exterior jets were more effective in increasing torque, and at best, the torque produced by the T1 jet increased by 132%, or more than double, and was reported as the peak of torque increase.Improvement of flow separation around the horizontal axis of the sixth phase wind turbine was investigated by installing air jets. Using Taguchi method and using control parameters, the optimal combinations, and the level of importance of the parameters in increasing torque production were obtained by analyzing the signal-to-noise ratio and variance, and the torques were optimized. It was found that the importance of the parameters on increasing the torque includes the ratio of speed, chord position and longitudinal position, respectively .So a turbine consisting of twelve jets with a width of 0.04 local chord was simulated and numerically solved in the chord positions of 0.1-0.3-0.5 and 0.7 with Fluent software 18.2 and kω-SST turbulence model. Longitudinal places consist of three parts: outer, middle and inner. The velocity ratios for the output jet are 0.2, 1.2, 2.2, 2.8 and 3.2. The results showed that torque changes are dependent on changes in dimensionless parameters such as jet velocity ratio, chord position and longitudinal position. The aerodynamic effects of double, triple and quadruple jets were compared with single jets and the increase in torque was observed due to the improvement of the flow pattern due to the reconnection of the current separated from the blade surface, especially at the blade tip. Exterior jets were more effective in increasing torque, and at best, the torque produced by the T1 jet increased by 132%, or more than double, and was reported as the peak of torque increase.https://jsfm.shahroodut.ac.ir/article_2650_e3eb458dfcc93b5b6286f3b6385db935.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Numerical simulation of electroosmotic flow in two micropumps with series connection to evaluate the increase in performance of integrated micropumpNumerical simulation of electroosmotic flow in two micropumps with series connection to evaluate the increase in performance of integrated micropump237251264010.22044/jsfm.2022.11412.3586FAHojjatShabgardDepartment of Mechanic Engineering University of BirjandSeyed AliMirbozorgiDepartment of mechanical engineering
University of BirjandHamidNiazmandDepartment of Mechanical Engineering, Faculty of Engineering, Ferdowsi university of Mashhad, Mashhad, IranJournal Article19700101Electrosmotic micropumps are a group of microfluidic devices in which the movement of a fluid stream is formed by the application of an external electric field. This field is generally applied to the micropump by means of two electrodes immersed in the electrolyte. How to install the current-carrying electrode plates in the electrolyte fluid and their placement on the passage of the fluid flow is an issue that can have adverse effects on the quality of operation of the micropump. In this article, a method can be used to overcome this problem. In this method, the electrode plates, instead of being placed in the path of the fluid flow, are connected to the wall of the micropump with the help of T-shaped connections and while affecting the fluid mass, they do not obstruct the flow of the fluid flow. Such a connection, in addition to solving the previous problem, has another advantage, which is the possibility of serializing the pumps and increasing their pressure head. All simulations performed in this paper are performed in a two-dimensional geometry between two parallel plates and the flow conditions are assumed to be steady state, laminar and incompressible. The finite volume method is used to solve the equations governing the fluid flow field, internal and external electric fields, and the distribution of positive and negative ion concentrations called Nernst-Planck. According to the results, serialization of two micropumps in comparison with micropumps of the same length increases the outlet pressure head by up to 80%.Electrosmotic micropumps are a group of microfluidic devices in which the movement of a fluid stream is formed by the application of an external electric field. This field is generally applied to the micropump by means of two electrodes immersed in the electrolyte. How to install the current-carrying electrode plates in the electrolyte fluid and their placement on the passage of the fluid flow is an issue that can have adverse effects on the quality of operation of the micropump. In this article, a method can be used to overcome this problem. In this method, the electrode plates, instead of being placed in the path of the fluid flow, are connected to the wall of the micropump with the help of T-shaped connections and while affecting the fluid mass, they do not obstruct the flow of the fluid flow. Such a connection, in addition to solving the previous problem, has another advantage, which is the possibility of serializing the pumps and increasing their pressure head. All simulations performed in this paper are performed in a two-dimensional geometry between two parallel plates and the flow conditions are assumed to be steady state, laminar and incompressible. The finite volume method is used to solve the equations governing the fluid flow field, internal and external electric fields, and the distribution of positive and negative ion concentrations called Nernst-Planck. According to the results, serialization of two micropumps in comparison with micropumps of the same length increases the outlet pressure head by up to 80%.https://jsfm.shahroodut.ac.ir/article_2640_c57ef088f030dd5ba5d7dcebbb0751fb.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Effect of inclination angle on convection heat transfer inside porous enclosure exposed to non uniform magnetic fieldEffect of inclination angle on convection heat transfer inside porous enclosure exposed to non uniform magnetic field253265265110.22044/jsfm.2022.8849.3002FAMohsenIzadiMechanical Engineering Department, Faculty of Engineering, Lorestan University, Khorramabad, IranJournal Article13980601Here, the effect of rotating cavity filled by porous materials exposed to two variable magnetic fields on the heat transfer natural convection is investigated. The two hot semicylinder are cooled by the heat transfer through the porous medium. The two magnetic fields affect the nanofluid flow and the heat transfer of the natural convection inside the porous cavity. The characteristic equations related to the fluid flow including the continuum equation, momentum and two nano-fluid and the solid-state matrix energy equations of the porous medium have been solved to predict the problem behavior. The influence of the cavity rotation angle on the streamlines and temperature field is investigated. The results show that increasing the rotation angle has oscillatory effects on the magnitude of the streamlines. For the rotation angles = 20 and = 100 the heat transfer via both phases is intensified. The rotation of the cavity depends on how the magnetic field-induced Lorentz and Kelvin forces amplify or weaken the heat transfer, thereby altering the Nusselt number of both phases of porous medium.Here, the effect of rotating cavity filled by porous materials exposed to two variable magnetic fields on the heat transfer natural convection is investigated. The two hot semicylinder are cooled by the heat transfer through the porous medium. The two magnetic fields affect the nanofluid flow and the heat transfer of the natural convection inside the porous cavity. The characteristic equations related to the fluid flow including the continuum equation, momentum and two nano-fluid and the solid-state matrix energy equations of the porous medium have been solved to predict the problem behavior. The influence of the cavity rotation angle on the streamlines and temperature field is investigated. The results show that increasing the rotation angle has oscillatory effects on the magnitude of the streamlines. For the rotation angles = 20 and = 100 the heat transfer via both phases is intensified. The rotation of the cavity depends on how the magnetic field-induced Lorentz and Kelvin forces amplify or weaken the heat transfer, thereby altering the Nusselt number of both phases of porous medium.https://jsfm.shahroodut.ac.ir/article_2651_b543ad94d33d0777535e55a85151c70d.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Wind Energy potential evaluation and customizing a H-rotor Turbine based on Tehran, Zahedan and Manjil climateWind Energy potential evaluation and customizing a H-rotor Turbine based on Tehran, Zahedan and Manjil climate267281264310.22044/jsfm.2022.11306.3486FASaeedKarimianTarbiat Modares universitySeyed SamSahamTarbiat Modares universityJournal Article14000803Using some small wind turbines which is both simple in fabrication and efficient in wind energy extraction is very attractive. In this research wind energy potential has been assessed for 3 distinct locations in Iran composing Tehran, Zahedan and Manjil. Consequently, a typical H-rotor wind turbine is being localized based on these locations climate. A baseline design has been introduced and a semi-analytical 3D method has been developed for design improvement and geometric modifications. The DMST algorithm has been embedded in the code and the validation analysis is being presented. Parametric study and the corresponding results have been investigated including the effect of wind velocity, number of blades, chord length and blade dimension. The performance issues are power coefficient and force coefficient. based on the results presented it has been revealed that changing geometric variables can improve the turbine characteristics by 20-40 percent. Therefore, it is possible to propose some localized layouts based on the spatial wind profile and wind power study. one may start with the presented framework and utilize the Genetic algorithm in order to achieve an optimized design in continuation.Using some small wind turbines which is both simple in fabrication and efficient in wind energy extraction is very attractive. In this research wind energy potential has been assessed for 3 distinct locations in Iran composing Tehran, Zahedan and Manjil. Consequently, a typical H-rotor wind turbine is being localized based on these locations climate. A baseline design has been introduced and a semi-analytical 3D method has been developed for design improvement and geometric modifications. The DMST algorithm has been embedded in the code and the validation analysis is being presented. Parametric study and the corresponding results have been investigated including the effect of wind velocity, number of blades, chord length and blade dimension. The performance issues are power coefficient and force coefficient. based on the results presented it has been revealed that changing geometric variables can improve the turbine characteristics by 20-40 percent. Therefore, it is possible to propose some localized layouts based on the spatial wind profile and wind power study. one may start with the presented framework and utilize the Genetic algorithm in order to achieve an optimized design in continuation.https://jsfm.shahroodut.ac.ir/article_2643_71284ef0ef88fa40605eb8da5b760ce0.pdfShahrood University of TechnologyJournal of Solid and Fluid Mechanics2251-947512520221122Experimental study of solar collector with helical coilExperimental study of solar collector with helical coil283292264910.22044/jsfm.2022.10757.3387FAMohammedAlmultashiFerdowsi UniversityMohammedMoghimandepartment of Mechanical Engineering/ College of Engineering/ Ferdowsi University of MashhadSabahAbdul A MeerAhlAlbayt University, Karbala, IraqJournal Article14000206The solar parabolic trough concentrator (PTC) is superior to all other solar collectors owing to its concentration ratio. Various methods are being employed to enhance the efficiency of the PTC system, the most common of which are enhancing the reflectivity of the collector surface, increasing the absorptive capacity of the absorber tube, using high thermal capacity fluid in the absorber tube, and using inserts in the flow of fluid in the absorber tube. In the present study, the parabolic trough is constructed of a mild steel sheet with a receiver made of copper positioned at the focal point, and water was used as the working fluid. Using a bare tube helical receiver with a 2-cm pitch and a black-coated helical receiver, we measured the temperature variations. The results showed that the maximum absorber temperature occurred on the 21st of June at 13.17 PM after maximum solar radiation, which was 148°C. The higher temperature at this time is due to higher instantaneous solar radiation. Also, the minimum collector receiver temperature recorded was on the 21st of December at 13.12 PM, after maximum solar radiation, which was 91°C.The solar parabolic trough concentrator (PTC) is superior to all other solar collectors owing to its concentration ratio. Various methods are being employed to enhance the efficiency of the PTC system, the most common of which are enhancing the reflectivity of the collector surface, increasing the absorptive capacity of the absorber tube, using high thermal capacity fluid in the absorber tube, and using inserts in the flow of fluid in the absorber tube. In the present study, the parabolic trough is constructed of a mild steel sheet with a receiver made of copper positioned at the focal point, and water was used as the working fluid. Using a bare tube helical receiver with a 2-cm pitch and a black-coated helical receiver, we measured the temperature variations. The results showed that the maximum absorber temperature occurred on the 21st of June at 13.17 PM after maximum solar radiation, which was 148°C. The higher temperature at this time is due to higher instantaneous solar radiation. Also, the minimum collector receiver temperature recorded was on the 21st of December at 13.12 PM, after maximum solar radiation, which was 91°C.https://jsfm.shahroodut.ac.ir/article_2649_49cc4b5fafa7298087d854075046dafc.pdf