Sharif University of TechnologyScientia Iranica1026-309832620250301Experimental investigation and multi-objective optimization of FDM process parameters for mechanical strength, dimensional accuracy, and cost using a hybrid algorithm2327210.24200/sci.2023.60960.7090ENMohammad AliZonoobiTehran International Campus, Sharif University of Technology, Tehran, Iran.HamidHaghshenas GorganiEngineering Skills Education Center, Sharif University of Technology, Tehran, Iran.DorinJavaherneshanDepartment of Mechanical Engineering, Aalto University, Espoo, Finland.Journal Article20220818Considering many advantages of 3D printing of polymers using Fused Deposition Modeling (FDM) technique and its service nature, achieving maximum customer satisfaction is very important. The satisfaction of each particular customer may be obtained by providing one or more different outputs of this process, which may not have the same weights. This paper concentrates on multi-objective optimization of three response variables, including tensile strength, dimensional accuracy, and production cost. Eight FDM process parameters containing orientation, layer thickness, infill density, nozzle temperature, print speed, number of shells, infill pattern, and print position have been selected. For carrying out experimental studies, specimens were designed based on Taguchi L27 and manufactured according to ASTM D368-(I) using Polylactic Acid (PLA). Then the signal-to-noise ratio is calculated, and the mathematical regression model of all outputs is obtained. Finally, an intuitive optimal Pareto front is presented to the customer rather than a single point. By repeating the proposed algorithm for eight other customers, the average satisfaction number of 88.56% indicates the efficiency of this method.https://scientiairanica.sharif.edu/article_23272_ec875c219fb592c5c647dac89c9ea555.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Analysis of Natural Convective Flow of Casson Fluid around an Inclined Rectangular Cylinder2332810.24200/sci.2023.60747.6968ENOlalekan AdebayoOlayemi- Department of Aeronautics and Astronautics, Kwara State University, P.M.B. 1530, Malete, Kwara State, Nigeria.
- School of Engineering, Cranfield University, Cranfield, MK43 0AL, United Kingdom.Tomisin FavourAjideDepartment of Aeronautics and Astronautics, Kwara State University, P.M.B. 1530, Malete, Kwara State, NigeriaAdebowale MartinsObalaluDepartment of Physics, Augustine University, Ilara-Epe, Lagos State, Nigeria.Muneer AbduljaleelIsmael- Department of Mechanical Engineering, Engineering College, University of Basrah, Basrah, Iraq.
- College of Engineering, University of Warith Al-Anbiyaa, Karbala, Iraq.Journal Article20220707This paper presents the natural convection around a tilted hot cylinder immersed in Casson fluid and enclosed by a square container. The parameters of Casson fluid are set to be (0.1≤η ≤ 1.0), aspect ratio (0.1≤AR ≤ 0.7), tilt angle (0^°≤γ ≤ 90^° ) and Rayleigh number (10^3≤Ra ≤ 10^6) are inspected to reveal their influences on Casson fluid flow and heat transfer. The governing equations were solved with COMSOL Multiphysics 5.6 software. The walls of the enclosure and the cylinder are fixed as T_c and T_h. Findings are delineated as stream functions, isothermal contours, and average Nusselt numbers. The study reveals that for the range of η, AR and Ra investigated, the rate of heat transfer of the enclosure wall increases with increasing η, AR and Ra; while for the heated rectangular obstacle, the rate of heat transfer decreases with AR growth but improves with increasing η and Ra. At Ra=106, γ increment results in heat transfer enhancement for the enclosure and cylinder walls. For Ra in the interval of 10^3≤Ra ≤ 10^5, the response of the thermal profiles of both the rectangular cylinder and enclosure walls to cylinder orientation depends on the value of Ra and γ considered.https://scientiairanica.sharif.edu/article_23328_b87b4cb32132c42b8823d85e6723a4a3.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Functionally graded nanobeams subjected to large deflection by considering surface effects2333910.24200/sci.2023.60997.7113ENYasserTaghipourDepartment of Mechanical Engineering, Sirjan University of Technology, Sirjan, Iran.MoslemZeinaliDepartment of Mechanical Engineering, Sirjan University of Technology, Sirjan, Iran.Journal Article20220913In the current study, structurally graded nanobeams with distributed load are subjected to a large deflection analysis that takes surface effects into account. The nanobeams Young's elasticity modulus changes with thickness under a power-law function. The displacement elements are presented, generalization of the Young-Laplace formula is employed to account for the surface effects, and the total Lagrangian finite element formulation is utilized to get the outcomes by cracking the system of nonlinear differential equations founded on the Timoshenko beams theory. The reliability and correctness of the findings are confirmed by comparison with previously published publications. The investigation is done into how various characteristics, including length-to-thickness ratio, material gradient index, boundary conditions, and surface effects, affect the outcomes. The findings demonstrate that, in the presence of surface effects, residual surface tension plays a significant influence on the deflection of nanobeams. Additionally, a comparison of the power-law and exponential kinds of Functionally Graded (FG) distribution is conducted in this study, and it is discovered that the FG materials with the power-law distribution are more applicable since they are less susceptible to surface effects than the exponential type.https://scientiairanica.sharif.edu/article_23339_d93533f93d20d0593923fa42a5b22696.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Assessment of energy consumption in a building considering combined ventilation method across four different climate zones in Iran2343610.24200/sci.2023.60805.7034ENNeginMoallemi KhiaviDepartment of Mechanical Engineering, Plastic Technology Institute Chief Researcher, Roozwin Industrial Complex, Ardabil, Iran.AsgarMinaeiDepartment of Mechanical Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.Journal Article20220731Natural ventilation is considered as a passive energy-efficient strategy that could provide desired thermal comfort conditions for residents and improve the indoor space conditions. However, the aim of the present study is to analyze the potential of natural ventilation in reducing energy consumption for cooling of the building in summer. Therefore, the amount of energy consumption for ventilation and cooling of a single-story building in the four different climate zones in Iran has been evaluated by Energy Plus. Afterwards, to evaluate the amount of the energy saving using natural ventilation, energy analysis has been performed for the reference building using a combined mode including natural ventilation and a mechanical cooling system. The considered climate zones include Tehran, Tabriz, Isfahan and Bandar-Abbas which are the most popular climate zones in Iran. The results show that the reduction percentage in energy consumption applying natural ventilation for Tabriz, Isfahan, Tehran and Bandar-Abbas are 18, 12, 10 and 3%, respectively. The highest percentage of energy saving is for Tabriz with a cold and dry climate and the lowest one is for Bandar-Abbas with hot and humid climate.https://scientiairanica.sharif.edu/article_23436_14cd882a94047118df70efde60ac9ba3.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Practical bifurcation analysis for the vibration’s proficiency and their influences on gas turbine operations: Towards the digitization of their monitoring2353010.24200/sci.2024.60787.6990ENYoucefMahrougLaboratory of Mechanics, Physics and Mathematical Modelling, University of Medea, 26000, Medea, Algeria.AhmedHafaifa- Applied Automation and Industrial Diagnostics Laboratory, Faculty of Science and Technology, University of Djelfa 17000 DZ, Algeria.
- Department of Electrical and Electronics Engineering, Faculty of Engineering and Natural Science, Istinye University, İstanbul, Turkey.AbdelhamidIratniFaculty of Science and Technology, University of Bordj Bou Arreridj, 34030 DZ, Algeria.MouloudGuemana- Applied Automation and Industrial Diagnostics Laboratory, Faculty of Science and Technology, University of Djelfa 17000 DZ, Algeria.
- Gas Turbine Joint Research Team, University of Djelfa, Djelfa 17000 DZ, Algeria.IlhamiColakDepartment of Electrical and Electronics Engineering, Faculty of Engineering and Natural Science, Istinye University, İstanbul, Turkey.Journal Article20220713The emergence of modern technology in the oil and gas sectors presents an opportunity to enhance productivity, minimize environmental impact and optimize the energy efficiency of these facilities, leading to increased economic benefits. In pursuit of sustainable development in gas-turbine operations, this study develops a mathematical model that is validated through experimental tests for monitoring the vibrations of an MS5002B gas turbine located in a gas compressor station. The primary objective is to determine the bifurcation indices, ensuring the continuous stability of the studied turbine's operating state while monitoring its vibrations in real-time. A comparison between the experimental and numerical results of the developed model is validated against real operating data, enabling predictions of the complex dynamic behaviors within the bearing-rotor system of the examined turbine. Robustness tests, based on real-time operating data, are conducted to analyze the impacts of undesirable effects that may disrupt the turbine system, as depicted in the bifurcation diagram. This approach facilitates the monitoring of the dynamic behavior of vibratory phenomena in the examined turbine, allowing for the establishment of reliable diagnostic elements to ensure component stability and prevent unscheduled production shutdowns. Ultimately, this approach enhances energy efficiency while delivering environmental and economic improvements.https://scientiairanica.sharif.edu/article_23530_e3f5722df3a539e66efc801194e752e4.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Impact of chemical reaction on magnetohydrodynamics non-Darcian mixed convective nanofluid flow past over a stretching sheet with non-uniform heat source/sink2364910.24200/sci.2024.60844.7017ENArindamSarkarDepartment of Mathematics, National Institute of Technology Jamshedpur, Jamshedpur, 831014, India.HiranmoyMondalDepartment of Applied Mathematics, Maulana Abul Kalam Azad University of Technology, West Bengal, Kolkata-700064, India.RajNandkeolyarDepartment of Mathematics, National Institute of Technology Jamshedpur, Jamshedpur, 831014, India.Journal Article20220725In the current perusal, we have discussed the impacts of free-forced convective heat-mass transportation on Magneto-Hydro-Dynamic (MHD), incompressible, non-Darcy nanofluid flow passing through a porous surface in the presence of an electrical field and a constant magnetic field with chemical reaction. A suitable similarity transformation is being used to non–dimensionalize the system of governing equations along with boundary conditions. The converted system has been solved numerically by operating the Spectral Quasi-Linearization Method (SQLM). The effect of various key parameters has been discussed graphically. Velocity seems to be decreasing with the Schmidt number, chemical reaction parameter, Brownian motion parameter, and Hartman number. The Hartman number and the Brinkman number decline the Bejan number in the neighborhood of the stretching sheet. Nevertheless, far from the stretching sheet, impacts of both Brinkman as well as Hartman number on the Bejan number is negligible. On the other hand, thermal layouts, concentration layouts, and entropy generation are enhanced with the increment in the Hartman number. For the physical interest the coefficients of the skin-friction, heat transfer coefficient, and local Sherwood number also has been determined numerically.https://scientiairanica.sharif.edu/article_23649_1f2841a6326c2154af2b5251b2378fde.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Numerical simulation of laminar flow and free convection heat transfer from an isothermal vertical flat plate2332910.24200/sci.2023.61098.7139ENAliBelhocineDepartment of Mechanical Engineering, University of Sciences and the Technology of Oran, L.P 1505 El-MNAOUER, USTO 31000 Oran, Algeria.NadicaStojanovicDepartment of Motor Vehicles and Motors, Faculty of Engineering, University of Kragujevac, 6 SestreJanjić STR., 34000 Kragujevac, Serbia.Oday IbraheemAbdullahDepartment of System Technologies and Mechanical Design Methodology, Hamburg University of Technology, Hamburg, Germany.Journal Article20220910In this modest work, we present a numerical study of the phenomenon of laminar natural convection in a vertical plate, whose wall was maintained at a constant temperature. It was assumed that the boundary layer problem was initially given in a two-dimensional flow even though the physical properties of the fluid were considered to be constant except for the density change with the temperature. The governing equations of the model have been transformed and simplified into a non-linear system of Ordinary Differential Equations (ODE) through the use of similarity variables which we were able to solve numerically using the Runge-Kutta method. This method has better opted for the numerical resolution of this system which was developed in FORTRAN code on the computer. The numerical results of the model were presented in tabular form and the velocity and temperature profiles for various Prandtl numbers were analyzed and depicted graphically. Also, the expressions of the mean heat transfer rate and the average Nusselt number for the whole plate were obtained in the analysis. The results were compared at the end with the numerical results obtained in the literature, showing that they were in good agreement.https://scientiairanica.sharif.edu/article_23329_baad44e173233446d74818684b66ec88.pdfSharif University of TechnologyScientia Iranica1026-309832620250301An investigation of mixed convection flow on a vertical flat plate of a saturated nanofluid in a porous medium near the stagnation point2341810.24200/sci.2023.60786.6991ENAliShokrgozar AbbasiDepartment of Mechanical Engineering, Payame Noor University, Tehran, Iran.Journal Article20220713In the present paper, a non-similar solution of a steady saturated nanofluid flow, heat, and mass transfer is investigated. The nanofluid flow is under dual effects of stagnation flow and natural convection heat transfer on a vertical flat plate in a porous medium. Effects of variations in thermophoresis, Brownian motion, and buoyancy force have been studied. The partial differential equations are transformed into six ordinary differential equations with appropriate non-similarity variables, which also consider the longitudinal coordinate of the x-axis. In order to solve, we have formed a set of fourteen ordinary differential equations of the first order. A complicated double method finds six unknown initial values in the boundary value problem. Variations of longitudinal velocity, shear stress, temperature, and nanoparticle volume fraction are considered as functions of transverse and longitudinal coordinates. As a result, the minimum accuracy of the first-order non-similar solution in regions very close to the stagnation point is 96%. Also, the velocity profile is observed to vary along the longitudinal x-axis near the stagnation point, which is an improvement over the existing knowledge which largely assumes a constant velocity profile throughout the stagnant flow region.https://scientiairanica.sharif.edu/article_23418_6b23ae52df0ff7af70835400b952dc4b.pdfSharif University of TechnologyScientia Iranica1026-309832620250301An efficient biogas-base tri-generation of power, heating and cooling integrating inverted Brayton and ejector transcritical CO2 cycles: Exergoeconomic evaluation2363310.24200/sci.2024.61064.7127ENAli AkbarDarabadi ZareFaculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran.FarzadMohammadkhaniDepartment of Mechanical Engineering, Engineering Faculty of Khoy, Urmia University of Technology, Urmia, Iran.MortazaYariFaculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran.Journal Article20220903In the present work, an efficient multigeneration system is proposed to meet diverse energy requirements such as power, heating, and cooling. The system consists of a biogas-fueled gas turbine cycle as the topping cycle, and a Brayton, an inverted Brayton, and also, a trans critical carbon dioxide refrigeration cycles with an ejector expansion as the bottoming cycles Using the ejector instead of compressor results in a reduction in the power consumption. Moreover, the required power of the refrigeration cycle can meet by the inverted Brayton cycle which eliminates the need for an external power source. The thermodynamic and exergoeconomic evaluations are done for the suggested system considering the energy and exergy efficiencies and total specific cost of the system as objective functions. Also, a parametric analysis is performed to specify the effects of decision variables on the system performance. The energy and exergy efficiencies and total cost rate of the system are determined as 79%, 44.4%, and 183.4 $/h, respectively. These values demonstrate that the energy and exergy efficiencies of the proposed system have been improved by 48.9% and 54%, respectively, compared to the gas turbine cycle. Also, the cost of produced electricity is calculated to be 52.84 $/MWh.https://scientiairanica.sharif.edu/article_23633_efafce25a4085c8a10dd15d3c7881887.pdfSharif University of TechnologyScientia Iranica1026-309832620250301Magnetorheological fluid: Basic principle, application, and trends2365410.24200/sci.2024.61094.7148ENS. VivekanandaSharmaDivision of Civil Engineering Karunya Institute of Technology and Sciences, IndiaG.HemalathaDivision of Civil Engineering Karunya Institute of Technology and Sciences, IndiaDanielC.Department of Civil Engineering, Hindustan Institute of Technology and Science, India0000-0002-4024-4742Journal Article20220913Magnetorheological Fluids (MRF) are used in a wide range of controlled systems. MRFs have found widespread commercial use, particularly in vibration control. MRF is a type of intelligent fluid found in oil carriers. A magnetic field raises a fluid's apparent viscosity until it becomes a viscoelastic solid. A variable magnetic field intensity controls the fluid's yield stress when it is active. Control-based applications can be created by using an electromagnet to control the fluid's ability to transmit force. In MRF, more nuanced ferrofluid particles are used. Brownian motion cannot suspend MR fluid particles in the carrier fluid due to their thickness. Brownian motion suspends nano-sized ferrofluid iron particles, which reduce sedimentation and increases the performance of the MRF. Dampers, brakes, bearings, pneumatic artificial muscles, optics finishing, fluid clutches, and aerospace all use MRF technology. The characteristics, applications, modes, and models of MRF are investigated in this paper. Understanding yielding, flow, and viscoelastic behavior in the presence of shearing fluxes are critical. Various applications of MRF in various domain of engineering is discussed with valid examples. In a concise manner, the author discusses the utility of MRF for active and semi-active vibration control systems.https://scientiairanica.sharif.edu/article_23654_ff33466056bb4f6ec2e22bbc6ba03ee2.pdf