Sharif University of TechnologyScientia Iranica1026-309829120220201Mechanical safety analysis of the gas lift completion string used for a high-pressure sandwich layer1122243210.24200/sci.2021.50161.1543ENW. LuoPetroleum Engineering Institute of Yangtze University, Wuhan, Hubei 430100, ChinaJ. WenLogging Technology and Engineering Research Institute of Yangtze University, Jingzhou, Hubei 434000, ChinaW. QiResearch and Development Center, Tuha Oilfield Company, CNPC, Shanshan, Xinjiang, 838202, ChinaMing Yang- Research Institute of Exploration and Development, Tuha Oileld Company, PetroChina, Hami, Xinjiang 839009, China.
- CNPC AMERICA LTD., VenezuelaJournal Article20180102This study examines the mechanical safety of a gas lift completion string in a certain oilfield, Algeria 438B block, having complex geological characteristics (a high salt and high-pressure sandwich). When an annulus is not supported within fluid column after unloading using conventional single-tube gas lift completion with positive lift oil production, inner pressure is so low that the pressure differential between the annulus and external casing is very large, which may damage the casing. Hence, a dual tube completion annulus filled with fluid that can resist pressure was used to overcome this problem, in the adjacent blocks using a gas lift production string with positive and reverse lift oil. However, this technology is complex and characterized by poor system reliability, large construction costs and maintenance difficulty. Considering the three aspects of a casing string, the squeeze strength, tensile strength and internal pressure strength, a gas lift completion string with dual concentric tubes and positive lift was preferably selected under conditions that have been verified as safe for production and a shut-in state. It was shown that this gas lift completion string design is feasible.Sharif University of TechnologyScientia Iranica1026-309829120220201Angle design of stator-rotor blades for VLH axial flow turbine using surrogate-based optimization13252233910.24200/sci.2021.53172.3099ENN. PholdeeSustainable Infrastructure Research and Department of Mechanical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen, 40002, ThailandW. NuantongDepartment of Mechatronics Engineering, Faculty of Engineering, Rajamangala University of Technology Isan, Khon Kaen Campus, Khon Kaen, 40000, ThailandS. TaechajedcadarungsriDepartment of Mechanical Engineering, Faculty of Engineering, Ubon Ratchathani University, Ubon Ratchathani, 34190, ThailandS. BureeratSustainable Infrastructure Research and Department of Mechanical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen, 40002, Thailand0000-0002-6332-1202Journal Article20190316This paper demonstrates design of a Very Low Head axial flow turbine using surrogate-based optimization. The design variables were blade angles between guide vanes and runner blades, whereas the objective function was turbine efficiency. A Latin Hypercube Sampling method was initially used to design the experiment with thirty sampling points, and a Large Eddy Simulation was modeled to analyze the flow for all sampling points. A correlation between design variables and the turbine efficiency was then evaluated using the surrogate models while the optimal design variables were identified. Also, several optimizers were used to tackle the proposed problem and their performances were investigated. The optimal design of blade angles \mathbit{\beta}_\mathbf{1}-\mathbit{\beta}_\mathbf{8} being 10o, 20o, 30o, 40o, 25o, 45o, 55o and 65o respectively, increased the turbine efficiency up to 89.87 %. The approach of using surrogate modeling was proved to be very effective and simple for optimizing a design of blade angles of stator-rotor and it can be applied for designing any other new blades.Sharif University of TechnologyScientia Iranica1026-309829120220201A quasi-3D modified strain gradient formulation for static bending of functionally graded micro beams resting on Winkler-Pasternak elastic foundation26402234510.24200/sci.2021.55000.4019ENM. GholamiSchool of Mechanical Engineering, Iran University of Science and Technology, Tehran, 16846, IranM. AlizadehSchool of Mechanical Engineering, Iran University of Science and Technology, Tehran, 16846, IranJournal Article20191209This paper presents the bending analysis of simply supported functionally graded (FG) size dependent beams based on modified strain gradient theory. The shear and normal deformations are considered in displacement field according to hyperbolic shear deformation theory. Governing equations and corresponding boundary conditions for FG micro beam are derived utilizing principle of minimum total potential energy. Mori–Tanaka homogenization scheme and the classical rule of mixture are used for prediction of material properties through the thickness. Effects of Winkler-Pasternak elastic foundation parameters are studied for different side to thickness ratios. Effects of different aspect ratios, elastic foundation parameters, power law gradient indexes and different loading conditions are investigated. The efficiency and accuracy of present model is demonstrated by comparing to the existing results in especial cases.Sharif University of TechnologyScientia Iranica1026-309829120220201Three dimensional prediction of stability lobes in end milling of thin-walled structures based on tool and workpiece dimensions41522235710.24200/sci.2021.56130.4565ENM. MahboubkhahDepartment of Mechanical Engineering, University of Tabriz, Tabriz, P.O. Box 51666{16471, IranM. R. MovahhedyDepartment of Mechanical Engineering, Sharif University of Technology, Tehran, IranA. Jodeiri FeiziDepartment of Mechanical Engineering, University of Tabriz, Tabriz, P.O. Box 51666{16471, IranJournal Article20200606Nowadays, researchers are very interested to investigate the dynamic behavior of the thin-walled structures during the machining process due to their broad application in aerospace, automotive industries and etc. One of the main problems in machining of thin-walled structures is unstable chatter vibrations, which causes the poor machined surface quality and decreases the system life span. In this regard, the main aim of this paper is to propose a practical method to solve the chatter instability problem during the milling process of thin-walled components. To this end, first the effects of geometrical parameters like workpiece height, thickness, and tool overhang, diameter and their ratios on the chatter stability are investigated. Then three dimensional stability lobe diagrams (SLDs) base on the mentioned parameters are presented for the first time. In which one can implement the mentioned diagrams to switch the unstable machining process to stable one by changing the value of the system parameters. Finally, the results obtained by the experimental test show that the presented three dimensional diagrams can be utilized to avoid chatter instability in the milling process.Sharif University of TechnologyScientia Iranica1026-309829120220201Minimizing the casting defects in high-pressure die casting using Taguchi analysis53692235910.24200/sci.2021.56545.4779ENS. TariqDepartment of Mechanical Engineering, Wah Engineering College, University of Wah, Wah Cantt, 47040, PakistanA. TariqDepartment of Mechanical Engineering, Wah Engineering College, University of Wah, Wah Cantt, 47040, Pakistan0000-0003-2333-2908M. MasudDepartment of Mechanical Engineering, Capital University of Science and Technology, Islamabad, 44000, PakistanZ. RehmanDepartment of Mechanical Engineering, Air University Islamabad, Aerospace and Aviation Campus, Kamra 43570, Pakistan0000-0002-7007-1387Journal Article20200804High-Pressure Die Casting (HPDC) is one of the major production processes of automotive industry, widely used to manufacture geometrically complex nonferrous castings. The mechanical strength and microstructure of HPDC-manufactured products changes with variation in several process control parameters such as injection pressure, molten temperature, 1st and 2nd stage plunger velocity, cooling temperature, etc. Since these process parameters directly affect casting quality, their optimum combination is needed to maximize the productivity of process and minimize casting defects such as porosity, pinholes, blowholes, inclusions, etc. Hence, to tackle this problem, an approach is presented in this paper that minimizes the major casting defect, i.e., porosity, in the HPDC process by optimizing controlling parameters through Design of Experiments (DOE) in combination with a Taguchi Analysis. The results obtained showed that cooling time, injection pressure, and 2nd stage plunger velocity have a major influence on the response factor (density of the cast part). It was also concluded that, by using a 178 bar injection pressure, 665 °C molten temperature, 5 second cooling time, 210 °C mold temperature, 0.20 m·s−1 1st stage plunger velocity, and 6.0 m·s−1 2nd stage plunger velocity, the rejection rate of the selected part due to porosity was reduced by 61%.Sharif University of TechnologyScientia Iranica1026-309829120220201A combined approximation method for nonlinear foam drainage equation70782236010.24200/sci.2021.56571.4792ENM. IzadiDepartment of Applied Mathematics, Faculty of Mathematics and Computer, Shahid Bahonar University of Kerman, Kerman, Iran0000-0002-6116-4928Journal Article20200808The aim of this study is to develop a combined approximative technique to find a numerical solution to the foam drainage equation arising in various absorption and distillation processes. In this approach, first, the discretization of time is performed with the aid of the Taylor expansion series. Hence, a collocation method based on novel Bessel polynomials is utilized for the space variable. Thus the solution is found by solving a linear system of algebraic equations at each time step in contrast to solving a nonlinear system. Numerical simulations are provided to check the accuracy<br />and efficiency of the presented algorithm. The numerical results are compared with exact<br />solutions as well as with the outcomes of other existing available numerical methods.Sharif University of TechnologyScientia Iranica1026-309829120220201Taguchi optimization of fused deposition modeling process parameters on mechanical characteristics of PLA + filament material79892236210.24200/sci.2021.57012.5020ENM. KamDepartment of Mechanical and Metal Technologies, Cumayeri Vocational School, Duzce University, 81700 Duzce, Turkey0000-0002-9813-559XA. IpekciDepartment of Mechanical and Metal Technologies, Cumayeri Vocational School, Duzce University, 81700 Duzce, Turkey0000-0001-9525-0536O. SengulDepartment of Mechanical Engineering, Duzce University, 81620, Duzce, TurkeyJournal Article20201019This study was realized to determine effects of Fused Deposition Modeling (FDM) process parameters on mechanical characteristics with Taguchi optimization method. Three different FDM process parameters used for modified Polylactic Acid (PLA+) filament material; filling structures (Rectilinear, Triangular, and Full Honeycomb), occupancy rates (10, 30, and 50 %) and table orientation (0, 60, and - 45°) was specified as variable parameters for experiments. Other parameters kept fixed for each tensile and izod impact test samples were printed according to the ISO 527 – Type IV and ISO 180-Type I standards. The results found tensile strength values and izod impact values directly proportionate with occupancy rate. The difference between the estimation model and the results of experiments did not exceed the maximum value of 1.8 %. Thus, using the equations derived from this optimization, printing parameters can be determined for the desired tensile strength and izod impact values. By improving the material properties using modified PLA+ filament material as observed in the results, it will be possible to provide support for researchers, design engineers and manufacturer to optimize raw-material usage and margin.Sharif University of TechnologyScientia Iranica1026-309829120220201Effects of chemical reactions, radiation, and activation energy on MHD buoyancy induced nano fluidflow past a vertical surface901002227310.24200/sci.2021.56835.4934ENG. Lakshmi DeviDepartment of Mathematics, School of Advanced Sciences, Vellore Institute of Technology, Vellore-632014, IndiaH. NiranjanDepartment of Mathematics, School of Advanced Sciences, Vellore Institute of Technology, Vellore-632014, India0000-0002-6024-1987S. SivasankaranDepartment of Mathematics, King Abdulaziz University, Jeddah 21589, Saudi ArabiaJournal Article20201028This paper explores the effects of thermal radiation, buoyancy force, chemical reaction, and activation energy on magnetohydrodynamic (MHD) nanofluid flow past a stretching vertical surface. The resulting nonlinear momentum, energy, solute, and nanoparticle concentration boundary layer equations are simplified by the transformation of similarity. The transformed equations solved numerically by using the shooting technique. For various related parameters, the corresponding results to the dimensionless velocity, temperature, solute, nanoparticle concentration profiles, Skin friction, local Nusselt number, local Sherwood number, and local nanoparticle Sherwood number are illustrated graphically. It is found that the temperature and nanoparticle concentration profiles increase on increasing thermal radiation and temperature difference parameters. With the increase of the regular buoyancy parameters, the local Nusselt number decreases on increasing the fitting rate constant, Biot number, and thermal radiation parameters.Sharif University of TechnologyScientia Iranica1026-309829120220201A CFD study of a flanged shrouded wind turbine: Effects of different flange surface types on output power1011082229710.24200/sci.2021.57513.5278ENN. MaftouniDepartment of Mechanical Engineering, Faculty of Engineering, Alzahra University, Tehran, IranM. TaghaddosiDepartment of Mechanical Engineering, Faculty of Engineering, Alzahra University, Tehran, IranJournal Article20210111There is a global trend to optimize energy harvesting from all energy resources including renewable energy. In this study, the focus is on improving the surface of flanges in flanged shrouded wind turbines to obtain more efficient systems. A CFD approach is utilized for this purpose. All models are identical in the entrance diameter, exit diameter, length of the diffuser, and the height of the flange, but each model is of a different flange surface type. Different surfaces are studied, including a simple surface and some furrowed surfaces. The validation reports that there is a strong correlation between the present study's outcomes and that of previously experimental results. The results show that the models with furrowed surface flange type lead to an increase in the wind velocity when approaching the wind turbine blades. This leads to about 5-7% more output power. Also, the results indicate that the maximum velocity occurs at about 5cm after the shroud entrance. Consequently, it is suggested that the wind turbine should be installed at that location inside the shroud, to obtain the optimum energy harvest.Sharif University of TechnologyScientia Iranica1026-309829120220201Experimental and statistical investigations of surface roughness, vibration, and energy consumption values of titanium alloy during machining using response surface method and grey relational analysis1091192238510.24200/sci.2021.57548.5296ENH. AkkusAutomotive Technology Program, Nigde Vocational School of Technical Sciences, Nigde Omer Halisdemir University, Nigde, P.O.
Box 51200, Turkey0000-0002-9033-309XJournal Article20210116This study aims to explain the interaction between the results measured in the turning operation. For this purpose, Ti 6Al-4V alloy workpiece was machined on CNC lathe. Surface roughness (Ra), vibration and energy consumption values were determined by turning. Experimental results were analyzed statistically. Response surface method (RSM) and grey relational analysis were used statistical analysis. In RSM analysis, regression equations, ANOVA, contour graphs, pertubation graphs, real and prediction graphs, % contribution graphs, most significant factor, optimum parameters, it is determined that the effective parameter in surface roughness, vibration and energy consumption is feed rate. Grey relational analysis steps and results are examined.