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text
article
2010
per
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Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
2
2
https://sjme.journals.sharif.edu/article_6428_bcbd087e7623ee5c12626c0797293566.pdf
THERMAL COMFORT DESIGN OF A RESIDENTIAL ROOM USING THE INVERSE METHID
G.
Imani
Faculty of Engineering, Dept. of Mechanical Tarbiat Modares University
author
Mehdi
maerefat
Faculty of Engineering, Department of Mechanical Engineering, Tarbiat Modarres University
author
F.
Kowsary
Faculty of Engineering, Dept.of Mechanical \\nUniversity of Tehran
author
A.
Zolfaghari
Faculty of Engineering, Dept. of Mechanical Tarbiat Modares University
author
text
article
2010
per
A new method to design the human thermal environment is presented in this study. The principle aim of this work is to find thermal comfort conditions for a sited person in a residential room by an inverse method of determination of the air and wall temperatures. The equation set obtained from the inverse modeling is ill-posed so, the first-order Tikhonov regularization method has been employed to well pose the mentioned equation set. The method leads to suitable solutions that satisfy the thermal comfort conditions within an acceptable accuracy and uniformity level without having any problems related to asymmetric radiation discomfort.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
3
10
https://sjme.journals.sharif.edu/article_5646_08557daab5afeb6f1b1fbea147de7161.pdf
IMPROVEMENT OF CONTRACTION PRESSURE DISTRIBUTION TO REDUCE WIND TUNNEL TURBULANCE INTENSITY
Mohammad Reza
soltani
Dept. of Aerospace Engineering Sharif University of Technology
author
K.
Ghorbanian
Dept. of Aerospace Engineering Sharif University of Technology
author
M.
Mirzaei
Dept. of Aerospace Engineering Sharif University of Technology
author
M.D.
Manshadi
Dept. of Mechanic and Aerospace Engineering\nMalek-ashtar University of Technology
author
text
article
2010
per
One of the main applications of wind tunnels is to produce a controllable and steady flow with minimum turbulence intensity in its working section. Instabilities and separation of flow in the inlet and outlet of the contraction are the main factors in increasing turbulence intensity in the test section. Forced transition using a trip strip is a suitable method for turbulence reduction in wind tunnels. In this investigation, subsonic wind tunnel experiments were conducted to study the effect of a tripped boundary layer on pressure distribution in the contraction region of the tunnel. Measurements were performed by installing a trip strip at four different positions in the convex portion of the contraction. The results show that installation of the trip strips has a significant effect on both turbulence and pressure distribution. The reduction in free stream turbulence and wall static pressure distribution was significantly affected with the location of the trip strip. For example, at X/L=0.79, the unfavorable pressure gradient is weaker and the instabilities are less than at other positions. Consequently, for this position, the lowest amount of turbulence intensity in the test section is obtained.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
11
19
https://sjme.journals.sharif.edu/article_5647_387bbe4b66c6249df68b21a526a71174.pdf
THE EFFECT OF FERRITE GRAIN SIZE ON MECHANICAL PROPERTIES OF DUAL PHASE (FERRITE-BAINITE) STEELS
Tayebeh
izadyar
Dept. of Materials Science and Engineering\nSharif University of Technology
author
A.A.
Ekrami
Dept. of Materials Science and Engineering\nSharif University of Technology
author
text
article
2010
per
In this research, the effect of ferrite grain size on mechanical properties of dual phase (ferrite-bainite) steels was investigated. Dual phase microstructures with different ferrite grain size were produced by heat treatment of AISI 4340 steel. The ferrite volume fraction was approximately constant and about 34\% in all produced dual phase microstructures.Tensile test results showed that both tensile and yield strengths decreased with increasing ferrite grain size, according to a Hall-Pech type relationship. Total elongation was also decreased by increasing ferrite grain size, while uniform elongation increased.Impact energy was also increased with decreasing ferrite grain size.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
21
25
https://sjme.journals.sharif.edu/article_5648_eda2e38f4a3ae1103d71a4c59c9d3eb4.pdf
FLEXIBILITY AND STRESS CONCENTRATION FACTORS IN PIPE BENDS UNDER COMBINED LOADINGS
K.
Naderan Than
Faculty of Engineerin, Dept. of Mechanical Engineering Shahid Chamran University of Ahvaz
author
M.
Shishehsaz
Faculty of Engineerin, Dept. of Mechanical Engineering Shahid Chamran University of Ahvaz
author
M.
Minaeefar
Faculty of Engineerin, Dept. of Mechanical Engineering Shahid Chamran University of Ahvaz
author
text
article
2010
per
The structural behavior of smooth pipe bends as a curved tube under in-plane and out-of plane bending moments with and without internal pressure, is investigated. Flexibility and stress concentration factors under such loadings are considered as characteristic parameters. These parameters are evaluated under variations of geometrical parameters and loading conditions using the finite element method; results are presented by diagrams. Also, the results obtained in the present study are compared with theoretical and approximate relations that exist in other references, and agreements or differences are indicated.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
27
37
https://sjme.journals.sharif.edu/article_5649_82086ba57207303d64ac1732fea48307.pdf
NUMERICAL SIMULATION OF 3D HYDROCARBON RESERVOIRS USING BLACKOIL MODEL AND AN IMPLICIT FINITE DIFFERENCE METHOD
R.M.H.
Khorasani
Islamic Azad University (Behbahan)
author
S.M.
Seid-Nasrolah
Research Institute of Petroleum Industry
author
M.T.
Manzari
School of Mechanical Engineering Sharif University of Technology
author
S.K.
Hannani
School of Mechanical Engineering Sharif University of Technology
author
text
article
2010
per
In this paper, a numerical method has been presented for hydrocarbon reservoir simulation in three-dimensions using a black-oil model. Here, it is assumed that reservoir fluid contains three-components (oil, gas and water), which can be present in three phases (Oil, Vapor and Aqua). Temperature effects are neglected, but rock compressibility and capillary pressure are included in the physical model. Governing equations for both saturated and under-saturated cases are presented. A finite difference numerical algorithm is devised to solve the problem. The equations are discretized using a cell-centered difference scheme in space and a backward Euler scheme in time. The linearization technique and details of the solution algorithm are presented. Two SPE comparative study problems, i.e. SPE-1 and SPE-8, are solved to verify the accuracy of the proposed method using existing scientific data. The numerical results obtained in this work are in good agreement with results obtained by some other commercial software.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
29
49
https://sjme.journals.sharif.edu/article_5650_22426a138565343903946f2374f22892.pdf
UTILIZATION OF VOF INTERFACE RECONSTRUCTION METHOD TO DEVELOP THE PPM METHOD FOR MULTIMATERIAL PROBLEMS
K.
Mazaheri
Faculty of Engineering, Dept. of Mechanical Tarbiat Modares University
author
k.
Mazaheri
Faculty of Engineering, Dept. of Mechanical Tarbiat Modares University
author
text
article
2010
per
Careless attention to interfaces may causes rigorous errors in the numerical simulation of multimaterial flows, even in high resolution numerical methods such as the PPM.To avoid this problem, interface tracking methods are used. In these methods, the position and geometry of interfaces are determined in each time step. Then the properties of mixed cells are calculated by specific relations that are named mixture model.In the present work, the PPM Godunov type method of Colella is implemented to solve a compressible flowfiled composed of two different fluids. Among several proposed interface tracking methods, the VOF method is selected.Two mixture models; the isobar-isoenergy and the constant volume fraction, are used, and the results of their implemetation are compared. The results indicate the importance of using a tracking method for multimaterial flow filed simulation. Current study shows that the isobar-isoenergy model have a better performance, with respect to the constant volume fraction method.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
39
49
https://sjme.journals.sharif.edu/article_5651_c795304d85bd1926c75dd5da34c9724c.pdf
INVESTIGATION EFFECT OF CO-ORDINATED AGENT ON MAGNETIC PROPERTIES OF HEXAGONAL BARIUM FERRITE NANO POWDER PRODUCED BY SOL-GEL COMBUSTION METHOD
A.
Shanaghi
Faculty of Engineering, Dept. of Materials \nTarbiat Modares University
author
A.R.
S.Rouhaghdam
Faculty of Engineering, Dept. of Materials \nTarbiat Modares University
author
M.K.
Besharati Givi
Faculty of Engineering, Dept. of Mechanical University of Tehran
author
text
article
2010
per
In the sol-gel combustion method, the types of precursor used to manufacture magnetic nano powder, are so important. Among these, the coordinated agent has affected particle size, calcination temperature and the magnetic properties of hexagonal barium ferrite nano powder. By considering the role of coordinating agents on the magnetic properties of particles produced by the sol-gel combustion method, in this paper, the effects of coordinated agents, such as citric acid and glycine during the sol-gel combustion step, on the structural, phase and magnetic properties of produced ferrite powders, were studied. The resultant powders were investigated by XRD, SEM and VSM measurement. The single domain size of BaFe$_{12}$O$_{19}$ powder with crystallite sizes less than 31nm was produced using a glycine precursor and 900$^\circ$C as the sintering temperature.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
61
67
https://sjme.journals.sharif.edu/article_5652_475869cb46467e84951a07e509139300.pdf
PREDICTION OF THE BLANK SHAPE AND FORMING SEVERITY IN GENERAL STAMPING PARTS BY USING THE INVERSE FINITE ELEMENT METHOD
A.
Asempour
School of Mechanical Engineering Sharif University of Technology
author
S.
Dormohammadi
School of Mechanical Engineering Sharif University of Technology
author
M.
Hajian
School of Mechanical Engineering Sharif University of Technology
author
text
article
2010
per
The purpose of this work is to introduce a quick tool for prediction of the blank geometry and forming severity in the stamping of general sheet metal parts. In this method, formability is evaluated by the prediction of wrinkles and splitting at the stage of design. In other words, having the 3D part geometry, the mechanical properties of the material and the physical conditions, all the mentioned goals can be achieved. To achieve this goal, the total deformation theory of plasticity has been employed. As the original position of the blank is on the horizontal plane, the vertical movement of each node during the deformation is known. Therefore the problem can be evaluated as a 2D problem. Also, to find an appropriate guess at the early stages of computation, a special unfolding technique has been used. The solution provides not only the optimum blank shape geometry, but, also, all the components of the strain. The results of the analyses for some industrial parts have been compared with some published experimental data and results obtained by other commercial software.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
69
75
https://sjme.journals.sharif.edu/article_5653_683645a593c50dec2f10f11270c24558.pdf
A SINGLE PHASE APPROACH TO DESIGN, TEST AND COMPARE THE PERFORMANCE OF AN INDUCTION TWO-FLUID NOZZLE
M.R.
Jahannama
Research Affairs Department, Engineering Research Institute Ministry of Jahad-Agriculture
author
S.
Shakhesi
Research Affairs Department, Engineering Research Institute Ministry of Jahad-Agriculture
author
text
article
2010
per
An induction internal-mixing two-fluid nozzle has been investigated. The nozzle design takes account of a single phase fluid mechanics viewpoint, in conjunction with the performance characteristics of a benchmark nozzle, which provides an approximate approach to the liquid conduit and the air throat parameters. The approach has been evaluated using an experimental setup capable of a simultaneous and steady supply of compressed air, liquid feed and high voltage to the nozzle. The compressed air plays a crucial role as a dielectric layer on the charging electrode, while the charging voltage improves the induction charging mechanism through strengthening the electric field intensity. At a constant voltage, there exists an optimum air pressure leading to a maximum spray specific charge, beyond which the charging efficiency declines. Although an increase in the liquid flowrate degrades charging efficiency, due to electrode wetting, it would be postponed to greater flowrates by applying higher air pressure. The nozzle performance, in addition to comparing well with the benchmark nozzle, shows a larger spray specific charge at higher pressures and voltages, as well as having the lower consumption of compressed air under all similar conditions.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
77
91
https://sjme.journals.sharif.edu/article_5654_6a798673b812c5c393628227666dda91.pdf
MODELING IMPACT ENERGY OF FUNCTIONALLY GRADED STEELS WITH CRACK DIVIDER CONFIGURATION
J.
Aghazadeh
Dept. of Mining and metallurgical Engineering\nAmirkabir University of Technology
author
A.
Nazari
A. Nazari\address{Faculty of Engineering\nIslamic Azad University Saveh Branch
author
text
article
2010
per
Functionally graded steels were produced via an electroslag remelting process using plain carbon and austenitic stainless steels as electrodes. The charpy impact resistance of functionally graded steel specimens in the form of a crack divider was investigated. The results obtained show that the impact energy of specimens depends on the type and volume fraction of the containing phases. According to the hardness profile and the area under the stress-strain curve obtained from the tensile test, two mathematical models have been presented for predicting the impact energy of specimens using the rule of mixtures. There is good agreement between experimental results and those acquired from two models.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
93
102
https://sjme.journals.sharif.edu/article_5655_fb65e8f81fafff15eaf9efdd12b8ed8c.pdf
HYDRODYNAMIC PERFORMANCE OF THE SURFACE PIERCING PROPELLERS (SPP) USING BOUNDARY ELEMENT METHO
h.
Ghasemi
Faculty of Marine Technology Amirkabir University of Technology
author
A.
Nazari
Marine Research Center, NEDSA
author
M.
Ghassabzadeh
Faculty of Marine Technology Amirkabir University of Technology
author
text
article
2010
per
Nowadays, SPP (surface piercing propellers) are employed for many high speed planing crafts with high efficiency and excellent maneuverability. These types of the propeller are working at two interface physical conditions (air and water) and hirgh RPM, so, calculation of the hydrodynamic performance of the SPP are very complicated job. There are some geometrical and physical parameters that are affected to the hydrodynamics performance. The important parameters which effect to the performance are defined, such as; number of blades, pitch, immersion ratio and shaft inclinations, etc. We applied the boundary element method (BEM) and especial boundary conditions taken from experimental data by Ferrando et al.$^{[1-5]}$ for solving the hydrodynamic performance of the SPP. Two propellers, SPP-101 and SPP-102, are selected for calculation of hydrodynamic performance at various conditions. The predicted numerical results show that the present method is a good computational tool for computations of the hydrodynamic characteristics of SPP.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
103
109
https://sjme.journals.sharif.edu/article_5656_ea39dce9f8de1c2f8de9f19887aac2aa.pdf
NUMERICAL MODELING OF AIRLIFT PUMP TO OPTIMIZE ITS PERFORMANCE
H.
Shams
Department of Mechanical Engineering, Sharif University
author
P.
Hanafizadeh
Department of Mechanical Engineering, Sharif University
author
M.H.
Saeedi
Department of Mechanical Engineering, Sharif University
author
text
article
2010
per
In this paper, the influence of performance parameters of airlift pumps, such as: pipe diameter, submergence ratio, flow regimes and pipe length, has been numerically investigated, and the design criteria of the airlift pump have been optimized. The results are compared with the experimental data and show that the present model is in good agreement with other models. The model is used to carry out parametric studies and to optimize the maximum efficiency under various operating conditions. The results show that there is an optimum diameter for a given set of pump operating conditions. The results are discussed for different submergence ratios and tube lengths, in order to increase the efficiency of an airlift pump.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
111
118
https://sjme.journals.sharif.edu/article_5657_5a2513aaf6ff6f4032f5bca27d0b6166.pdf
BEHAVIOR MODELS RECONSTRUCTION OF SCARF JOINT OF BIMETAL CAUSED BY BLAST PRESSURE
J.
Zamani
Dept. of Mechanical Engineering K.N. Toosi University of Technology
author
S.M.
Bagheri
Dept. of Mechanical Engineering K.N. Toosi University of Technology
author
A.M.
Amrani
Dept. of Material Engineering Malek-ashtar University of Technology
author
text
article
2010
per
In this paper, the bonding ability of copper and aluminum with explosion welding was experimentally investigated using different ratio metal thicknesses.First of all, the scarf joint is described, then, all parameters of a table, named the weld ability window, were calculated. Experimental studies showed that aluminum and copper plates were explosively welded; employing appropriate equations for the explosive loading ratio. The bond strength was investigated using special shear strength tests.According to shear test results, when the calculated values of minimum plate velocities along the interface were related to the locations in which separation appears, a proper relationship between the explosive loading ratio and the minimum plate velocity is obtained with a correlation factor.Consequently, the scarf joint not only provides a method of making a bond between dissimilar materials, but, also, is able to evaluate the main equations in the explosive welding process.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
119
127
https://sjme.journals.sharif.edu/article_5658_21ac59006c27c9d4f588a1cc2a3a81f3.pdf
EFFECT OF VEHICLE SUSPENSION PARAMETERS ON SUVS ROLLING STABILITY INVESTIGATION
R.
kazemi
Dept. of Mechanical Engineering K.N. Toosi University of Technology
author
S.
Badeleh
Dept. of Mechanical Engineering K.N. Toosi University of Technology
author
text
article
2010
per
One of the most serious accidents is rollover. The goal of this research is to investigate the effect of vehicle suspension parameters on a SUVs rolling stability in rollover conditions.For this purpose, dynamic modeling is determined by consideration of a semi static rollover vehicle in rigid conditions and with suspension systems. After that, the dynamic stability index (DSI) is specified. To have a comprehensive result, a full vehicle model with 105 degrees of freedom in ADAMS was simulated.Finally, with the validating model, the dynamic parameters of a suspension system were changed in their specific range, and the effect of those parameters in a rollover critical condition, during a J-turn and fishhook maneuver, has been determined.For the purpose of the rollover behavior investigation, the Static Stability Factor (SSF) and the Dynamic Stability Factor (DSF) were recorded, and it was determined which parameters were useful for changes in the process of vehicle design, in order to obtain roll stability and a safer vehicle.
Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
129
139
https://sjme.journals.sharif.edu/article_5660_f797cf7702e3eb5eb7e09861a4dd6147.pdf
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text
article
2010
per
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Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
142
146
https://sjme.journals.sharif.edu/article_6427_d1892ef3f99be4e02672a6f3cf6461da.pdf
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text
article
2010
per
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Sharif Journal of Mechanical Engineering
Sharif University of Technology
2676-4725
26.3
v.
1
no.
2010
147
148
https://sjme.journals.sharif.edu/article_6429_91e641fc144efdedd2a44c03525faad9.pdf