A New Method for Extracting an Optimal Sliding Surface and Its Application to Control of a Quarter Car Active Suspension System
Seyyed A.
Zahiripour
Tehran- narmak- iran university of science & technology
author
A. A.
Jalali
استاد، دانشگاه علم و صنعت ایران
author
text
article
2015
per
In this paper, a new method for extracting sliding surface has been presented about a linear system with parametric uncertainties with known bound. In the proposed method, common signal of first order sliding mode control has been applied to the system and then the sliding surface is extracted as a virtual controller with the aim of minimizing a cost function. The main advantage of the proposed method is the possibility of setting the distance of the state trajectory from the sliding surface setting one of the design parameters. Thus, It is possible to near the ultimate goal of sliding mode control, i.e. staying the state trajectory on the sliding surface, without increasing the degree of sliding mode control, while the amount of used energy will be controlled, too. In order to show the efficiency of the method, a quarter car active suspension system has been chosen and the proposed method in the selection of position subsystem sliding surface is used.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
1
15
http://jsfm.shahroodut.ac.ir/article_504_32a224d544a3d645336aca174a38000c.pdf
dx.doi.org/10.22044/jsfm.2015.504
Adaptive Fuzzy Control of a Mobile Manipulator Robot
M. M.
Fateh
Shahrood University of Technology
author
M.
Abedinzadeh Shahri
کارشناس ارشد رباتیک،دانشکده مهندسی برق، دانشگاه شاهرود، شاهرود
author
text
article
2015
per
A mobile manipulator robot is known as a complex system due to some properties such as coupling between the manipulator and mobile chassis, holonomic and nonholonomic constraints, multivariable and nonlinear dynamics. The control of robot faces the external disturbance, parametric uncertainty and unmodeled dynamics. Therefore, the use of an adaptive fuzzy system is suggested for its capability in overcoming uncertainties and approximating of nonlinear functions based on the universal approximation theorem. However, the tracking error does not converge asymptotically to zero due to the approximation error of the fuzzy system. This paper presents a novel adaptive fuzzy control for a mobile manipulator robot. The novelty of paper is compensating the approximation error of fuzzy system for asymptotic convergence in tracking the desired trajectory in the presence of uncertainties. For this purpose, the closed loop system in the error space converges to a linear system with poles having negative real parts. The control design consists of two parts; the kinematic control and dynamic control in which the novelty is for the dynamic control. The dynamic modeling and motion control of the nonholonomic wheeled mobile manipulator robot is considered in this paper. Advantages of the proposed design are the simplicity and very good performance in tracking of the desired trajectory in the presence of uncertainties. The stability of control system and convergence to the desired trajectory are proven by the Lyapunov method. The simulation results show the superiority of the proposed control over a robust adaptive control.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
17
27
http://jsfm.shahroodut.ac.ir/article_413_a5588846a881fcc4c4f256efa9f59511.pdf
dx.doi.org/10.22044/jsfm.2015.413
Solution of Nonlinear Incompressible Hyperelastic Problems by Isogeometric Analysis Method
B.
Hassani
استاد، دانشکده مکانیک، دانشگاه فردوسی مشهد
author
Seyed M.
Tavakkoli
استادیار،دانشکده عمران،دانشگاه صنعتی شاهرود،شاهرود
author
M
Ardiani
دانش آموخته کارشناسی ارشد،دانشکده عمران،دانشگاه صنعتی شاهرود،شاهرود
author
text
article
2015
per
This article is devoted to the derivation of formulation and isogeometric solution of nonlinear incompressible elastic problems, known as incompressible hyperelasticity. After problem definition, the governing equations are linearized for employing the Newton-Raphson iteration method. Then, the problem is discretized by using concepts of isogeometric analysis method and its solution algorithm is devised. To demonstrate the performance of the proposed approach, the obtained results are compared with finite elements. Due to large deformations in this kind of problems, the finite element method requires a relatively large number of elements, as well as the need for remeshings in some problems, that results in a large system of equations with a high computational cost. In the isogeometric analysis method, using B-Spline and NURBS (Non-Uniform Rational B-Spline) basis functions provides us with a good flexibility in modeling of geometry without any need for further remeshings. The examples studied in this article indicate that by using the isogeometric approach good quality results are obtained with a smaller system of equations and less computational cost. Also, influence of Gauss integration points for the incompressible materials are investigated.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
29
41
http://jsfm.shahroodut.ac.ir/article_429_f8c15014ac45534a11db1dade59c8ff7.pdf
dx.doi.org/10.22044/jsfm.2015.429
Experimental investigation of repeated low velocity impact on GLARE
with various energy levels
S.M.R.
Khalili
استاد، مرکز عالی تحقیقات مواد و سازههای پیشرفته و هوشمند دانشکده مهندسی مکانیک، دانشگاه صنعتی خواجه نصیر، تهران
author
R.
Ghajar
استاد، آزمایشگاه خواص مکانیکی دانشکده مهندسی مکانیک، دانشگاه صنعتی خواجه نصیر، تهران
author
M.
Yarmohammad Tooski
PhD Student, Mech. Eng., K.N.ToosiUniv. of Tech., Tehran, Iran
author
R.
Alderliesten
دانشیار، دانشکده مهندسی هوافضا، دانشگاه پلی تکنیک دلفت، دلفت
author
text
article
2015
per
In this study, an experimental investigation of repeated low velocity impact is performed on GLARE using drop weight testing machine. After the first impact on the plate, the second impact energy decreases and stays constant until the last impact. Damage due to repeated impact is investigated using visual inspection and C-scan. Three categories namely, no damage, small damage and serious damage are happened as a result of the first impact on the plate. The number of impacts required for the penetration is increased with decrease of the second impact energy. The threshold limit energy is defined as the maximum impact energy in repeated impact after the first impact which causes no damage on the specimen. For the successive impact energy larger than the threshold limit energy, the number of impacts becomes important, while for the successive impacts energies smaller than threshold limit energy, the number of impact has inconsiderable effect on damage occurrence.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
43
56
http://jsfm.shahroodut.ac.ir/article_505_34727724586d96e1e73b560751df7ce0.pdf
dx.doi.org/10.22044/jsfm.2015.505
Free and Force Vibration Analysis of Cracked Euler-Bernoulli Beam with Spectral Finite Element Method
V.
Sarvestan
MSc/Isfahan University of Technology
author
H. R.
Mirdamadi
Associate professor of department of mechanical engineering of Isfahan University of Technology
author
M.
Ghayour
Professor/Isfahan University of Technology
author
text
article
2015
per
In this article, a spectral finite element (SFE) formulation and its solution are described for free and force vibrations of cracked Euler-Bernoulli beam. The formulation based on SFE algorithm includes deriving partial differential equations of motion, spectral displacement field, dynamic shape functions, and dynamic stiffness matrix. Frequency-domain dynamic shape functions are derived from an exact solution of governing wave equations. The cracked beam with an open crack is modeled as two segments connected by a massless rotational spring at the crack position and frequency-domain dynamic stiffness matrix for cracked Euler-Bernoulli beam is extracted. By considering free vibration of the cracked beam, its natural frequencies are derived for different boundary conditions. In the SFE model, It is possible to represent the whole length of beam only by two spectral elements, while it may not be possible to do that in finite element (FE) model, for reaching the same order of accuracy. The accuracy of results obtained from SFE formulation is compared with that of either FE method or analytical formulations. The SFE results display remarkable superiority with respect to those of FE, for reducing the number of elements as well as increasing numerical accuracy.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
57
70
http://jsfm.shahroodut.ac.ir/article_506_640e28beabe1d6726630a9c9ec40132d.pdf
dx.doi.org/10.22044/jsfm.2015.506
Development of MAFVRO to Randomly Excited Vibration Systems to Derive the Natural Frequencies and Mode Shapes
M.
Rezaee
Assoc. Prof, Mech. Eng., University of Tabriz., Tabriz, Iran
author
Gh.
Fattahi
Msc of Mech. Eng., University of Tabriz., Tabriz, Iran
author
text
article
2015
per
MAFVRO is one of the out-put only modal analysis methods which is able to determine the modal parameters of a vibration system through the free vibration responses. It is worth to note that most of the vibration systems are subjected to random excitations. Therefore, in such cases, the traditional MAFVRO cannot extract the modal parameters. In this study, the mentioned method is developed to randomly excited vibration systems. Then, the modified MAFVRO is applied to a randomly excited vibration system. The random excitation has been considered as a set of white noises which are applied to all masses of a discrete system. Then by employing the developed method, the estimated results have been compared with those obtained through the structural eigenvalue problem. Comparing the results reveals that the developed method can give the natural frequencies and mode shapes of a randomly excited system with a good accuracy, but it estimates the damping ratios lower than their exact values. In addition, the effect of the noise on the accuracy of the estimated modal parameters have been investigated.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
71
81
http://jsfm.shahroodut.ac.ir/article_437_3a35e00bfc3f25b51bf0f1aeebee7902.pdf
dx.doi.org/10.22044/jsfm.2015.437
Damage Diagnosis of the Beam-Like Structures Using Recued Model Updating and Iterative Method
M.
Ettefagh
استادیار، دانشکده فنی مهندسی مکانیک دانشگاه تبریز
author
H.
Akbari
فارغ التحصیل مقطع کارشناسی ارشد، مهندسی مکانیک دانشگاه تبریز
author
text
article
2015
per
Nowadays, damage diagnosis of the engineering structures, applying vibration signal for early damage identifying during normal operation of the structure or after some disasters such as earthquake are very important from academic and technology viewpoints. Among different methods, proposed for damage diagnosis of the structures, the methods, based on FE model updating using modal analysis features are very important because of its practicability such that there are many researches in this field. Also because of node measurement limitations in real structures, model reduction is accompanied with damage detection methods. In addition for on-line applications of the mentioned methods for structural health monitoring with complex and intensive FE modeling, speed and accuracy increasing has attracted many researchers’ attentions. In this paper one of new model updating methods, which is lately proposed and proved to be accurate and fast, are applied for designing a damage diagnosis method. A beam, modeled with FE, has been considered with artificial damage on it is simulated in MATLAB for studying the proposed methods’ abilities and the noise effects on the method was studied exactly. Additionally, for studying the capability of the method in practice, the proposed method was applied on laboratory beam and the results were studied.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
83
97
http://jsfm.shahroodut.ac.ir/article_507_cb1585ed8e9f954ae52c169e8b18aadc.pdf
dx.doi.org/10.22044/jsfm.2015.507
Thermo-Mechanical Buckling Analysis of FGM Plates with Circular Cut Out
A.R.
Shaterzadeh
Assistant Prof., Mech. Eng., Shahrood Univ., Shahrood, Iran
author
text
article
2015
per
In this paper, thermo mechanical buckling of functionally graded plates (FG Plates) with circular cutout and subjected to combined thermal and mechanical loads are investigated by Finite Element Method (FEM). Unlike other studies in which the plate is subjected to only one type of loading at once, in present study it was assumed that mechanical and thermal loads are applied simultaneously. The material properties are assumed to vary across plate thickness according to power law distribution of the volume fraction of constituents. The plate formulation is based on first order shear deformation theory (FSDT) and element stiffness matrices are derived based on principle of minimum potential energy. A flexible mesh generation algorithm is prepared in which the mesh density around the hole can be controlled easily. After validating the results of developed finite element code with those available in the literature the effect of boundary conditions in edges of plate and cut out, plate aspect ratio and cut out size on thermo mechanical buckling behavior of FG plates are studied thoroughly and stability boundary graphs are presented. Finally useful conclusions are presented.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
99
109
http://jsfm.shahroodut.ac.ir/article_431_2284237d551775661f2a97c0215897d4.pdf
dx.doi.org/10.22044/jsfm.2015.431
Improving the Accuracy of Crack Length Measurement in Clay Brick Using Machine Vision
Kh.
Khalili
Ph.D. President University of Birjand, Birjand, Iran
author
M.
Vahidnia
MS, Mech. Eng, University of Birjand, Birjand, Iran
author
S.
Khishe
Ph.D. Student, Mech. Eng, University of Birjand, Birjand, Iran
author
text
article
2015
per
In the current paper a new method is introduced to analyze and measure the cracks dimensions in solid materials such as mechanical tools and bricks. Since the cracks do not have a regular or predictable shape, in order to achieve the exact dimensions of such cracks, the conventional mathematical formulas are by no means applicable. Hence, while studying different crack analyzing methods, we argue on their faults and limits and propose our method which aims to measure the crack dimensions in a solid object by utilizing machine vision, image capturing and image processing techniques. We define new algorithms and perform picture scaling in real dimensions and analyze the acquired data to obtain the most precise results. This optimal machine vision technique is performed in two different ways. The first method is based on the measurement of the length of the image skeleton, while the second technique is based on measuring the half of the perimeter of the crack’s image. After obtaining the measurements, we optimize the results with the help of some pre-defined algorithms. It is shown that our proposed algorithms provide a reliable method which can be used to measure any crack dimensions. Also, we apply these techniques on a sample brick with some random cracks on it. After gaining the binary images, filters are applied to gain the best results among all images.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
111
122
http://jsfm.shahroodut.ac.ir/article_435_fd9862c61b3a56d26e01e6221186b47a.pdf
dx.doi.org/10.22044/jsfm.2015.435
Modeling of Mixed Mode Fracture Tests Using Extended Finite Element Method
A.
Abbaszadeh Bidokhti
PhD Student, Mech. Eng., K.N. Toosi Univ of Tech., Tehran, Iran
author
A. R.
Shahani
Prof., Mech. Eng., K.N. Toosi Univ of Tech., Tehran, Iran
author
text
article
2015
per
In the present study, a mixed mode fracture specimen was simulated by the extended finite element method. For this, a specimen called "Diagonally loaded square plate" was selected. For this specimen, experimental test results are available. The loading process including the fracture and crack growth is simulated. Displacement control loading is considered. The crack growth increment and direction are determined using the fracture criteria. Various test specimens are simulated using a model with the fixed mesh. Therefore, computation costs has decreased dramatically. Furthermore, numerical integration in the enriched elements is studied and the optimum number of gauss points in these elements are determinrd. Comparing the results of the extended finite element method with the experimental data show that the critical fracture load and the stress intensity factors at the fracture moment differ less than 10%. Furthermore, there is a convincing agreement between the crack growth path in the experimental test results and numerical analysis by the extended finite element method.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
123
137
http://jsfm.shahroodut.ac.ir/article_508_2046a08c2e937e7d9969ac7f87597786.pdf
dx.doi.org/10.22044/jsfm.2015.508
A New Approach to Identify the Ductile Damage Constants of Seamed Metallic Tube Using Hydro-Bulging Process
H.
Ghaforian Nosrati
دانشجوی کارشناسی ارشد، مهندسی مکانیک، دانشگاه شاهرود
author
M.
Gerdooei
استادیار، دانشکدهی مهندسی مکانیک، دانشگاه شاهرود
author
M.
Falahati Naghibi
دانشجوی کارشناسی ارشد، مهندسی مکانیک، دانشگاه شاهرود
author
text
article
2015
per
In present research, the numerical and experimental investigation of progressive ductile damage has been conducted in free bulging of 304 stainless steel seamed tube using oil pressure. In the numerical section, using the Lagrangian finite element method with ABAQUS/Explicit solver, the seam weld simulated as a thin strip, contains non-homogeneity factors of strength and formability. Forming Limit Diagram (FLD) criterion was used as a measure of damage initiation, as well as effective plastic displacement factor with linear approach in order to model damage evolution. In the experimental section, tensile test of tube has been conducted to attain mechanical properties and also tube free bulging has been perform. Maximum bulging diameter of tube and critical pressure were recorded at the moment of bursting. In numerical analysis, the effect of material non-homogeneity factor on critical pressure, also the outcome of effective plastic displacement on the maximum bulging diameter investigated and compared with experiments. Finally, the optimum values of non-homogeneity factor and effective plastic displacement obtained respectively equal to 0.9 and 0.05 Using these factors, the accuracy of numerical prediction for tube diameter and oil pressure at bursing moment were more than 99%.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
139
151
http://jsfm.shahroodut.ac.ir/article_509_412b0c7022262acf43ff1e7dc9e66811.pdf
dx.doi.org/10.22044/jsfm.2015.509
Elastic-Plastic Modeling of the Residual Stresses Caused by Laser Beam Welding in Aerospace Structures
V.
Nategh
M. Sc., Mech. Eng. Dept., Urmia Univ., Urmia, Iran
author
S.
Rash Ahmadi
Assoc. Prof., Mech. Eng. Dept., Urmia Univ., Urmia, Iran
author
K.
Karimi
M. Sc., Mech. Eng. Dept., Urmia Univ., Urmia, Iran
author
text
article
2015
per
An appropriate joining technology is the laser beam welding process, because of its low localized energy input leading to low distortion, high strength of the joint and high processing speeds. The growing of aircraft industry in reducing the weight of aerospace structure has led the introduction of laser beam welding into the fabrication of aerospace structure with stiffeners, instead of riveted joints. In the present paper an analytical model for calculation of the residual stresses induced by laser welding is proposed and numerically validated. The aim of this work is to study the transverse residual stress distribution of plates made of an aluminum alloy 6061-T6, which is used for fabrication of fuselage panels. The results show that, if the maximum stress amount induced in the workpiece does not exceed the material yield stress, no plastic penetration will occur and there will be no residual stress. It was found that high stresses are developing close to the plate surface while these stresses decrease rapidly to almost zero values at the lower surface. An ideal elastic-plastic material curve was assumed. Good accordance is found between the calculated and numerical results.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
153
162
http://jsfm.shahroodut.ac.ir/article_510_4b57cb9aea39cba4efca44a6e59a034a.pdf
dx.doi.org/10.22044/jsfm.2015.510
Designing Optimal PID Controller Using Modified Particle Swarm Optimization
M.
Moradi Zirkohi
استادیار کنترل، دانشکده فنی و مهندسی، دانشگاه صنعتی خاتم الانبیاء بهبهان، بهبهان، ایران
author
text
article
2015
per
In this paper, designing optimal PID controller using modified particle swarm optimization is presented. The advantage of this new method compared to conventional methods of controller design is that it is not limited to a certain class of systems. In designing phase, sum of rising time, settling time, overshoot and integral of squared-error are minimized. There kind of particle swarm optimization algorithms such as ePSO, mPSO and sPSO are compared with other methods of optimization including Ant Colony. The results clearly show how superior the new proposed method is to the other methods. The proposed method differs from the other optimization algorithms in such a way that, the proposed algorithm does not need a velocity equation. The position of the particle is updated directly by extrapolating the current particle position with the global best particle position obtained so far.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
163
168
http://jsfm.shahroodut.ac.ir/article_424_04cbec867aac9011c3b4287c4465ca59.pdf
dx.doi.org/10.22044/jsfm.2015.424
Airfoil Profile Reformation of Bladeless Fan and Investigation of Flow Increase Curve
M.
Jafari
کارشناس ارشد، دانشکده مهندسی مکانیک، دانشگاه صنعتی شریف
author
H.
Afshin
استادیار، دانشکده مهندسی مکانیک، دانشگاه صنعتی شریف
author
B.
Farhanieh
Professor Prof., Mech. Eng., Sharif University of Technology, Tehran, Iran
author
text
article
2015
per
In the present investigation, in spite ofintroducing the effective parameters in the Bladeless fan performance,the profile of fan cross section was studied precisely because it is the most important sectionof designing this kind of fan. In order to modify the fan cross section and by considering the similarity of bladeless fans to airfoils, five profiles were chosen among the standard airfoil profiles by considering the important geometric parameters such asradius of leading edge, maximum thickness of airfoil compatible with the original airfoil. In addition, five profile were designed to create uniform airflow in front of fan and to prevent the separation of flow as well as the manufacturing criteria. By solving the momentum and continuity equations for incompressible fluid, the flow was analyzed numerically in 3D form. The aerodynamic characteristics of the designed airfoils and the original airfoil of the Bladeless fan wereindicated and compared to eachother.The fan was located in the centerof a 4×2×2m room and Eppler473 airfoil profile was used as the cross section of this fan.Accoring tothe obtainednumerical results, the flow increase curve of the fan versus different inlet flowrate was depicted. The flow increase curve shows that the outlet flow rate increasedlinearely by increasing the inlet flow rate.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
169
179
http://jsfm.shahroodut.ac.ir/article_427_7056fc09c14f54b5e6bec1d1ab9f4adb.pdf
dx.doi.org/10.22044/jsfm.2015.427
Thermodynamic Simulation of Ejector-Expansion Refrigerator Cooler
M.
Tahani
Assist. Prof., Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
author
S.
Shamsodini
کارشناسی ارشد، دانشگاه سیستان وبلوچستان
author
S.
Farahat
دانشیار، دانشگاه سیستان و بلوچستان
author
A.
Rabani
M.Sc. Student, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
author
text
article
2015
per
On hot days, due to the high power consumption of the compressor, using the refrigeration cycles cause to increase in energy consumption. According to lack of fossil fuels, refrigeration consumption reduction is very valuable. In this paper, simulation and design of a refrigeration cycle are presented that ejector and separator added to a conventional compression cycle. These changes, can reduce the power consumption of refrigerator. Comparison results show with the addition of ejector to conventional compression cycle, depending on the type of fluid and the temperature of the condenser and evaporator, lead to energy saving up to 35%. Also, whatever temperature difference between evaporator and condenser increases, or at the same temperature difference between the condenser and the evaporator, as lower evaporator temperature, coefficient performance of ejection-compression cooler is better than conventional refrigerant. In comparision between working fluids, Ammonia has the minimum coefficient of performance improvement and one reason for increased compression ratio is that this fluid has the lowest increasing compression ratio. The result show that R290 and R134a have the highest improvement coefficient of performance because the operation of these fluids associated with the highest increasing compression ratio.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
181
189
http://jsfm.shahroodut.ac.ir/article_511_a92a70c1b3a1eb5e6b586a42647b95f4.pdf
dx.doi.org/10.22044/jsfm.2015.511
Experimental Investigation on Low Swirl Premixed Combustion and Effects of Geometrical Parameters on Its Performance
Seyyed I.
Pishbin
استادیار، گروه مهندسی مکانیک، دانشگاه خیام، مشهد، ایران (رئیس پژوهش وفناوری، شرکت گاز استان خراسان رضوی)
author
M.
Ghazikhani
استاد، گروه مهندسی مکانیک، دانشگاه فردوسی مشهد، مشهد، ایران
author
Seyyed M. R.
Modarres Razavi
استاد، گروه مهندسی مکانیک، دانشگاه فردوسی مشهد، مشهد، ایران
author
text
article
2015
per
Low swirl burner provides an effective and low cost solution for stable lean premixed combustion. Several studies have been conducted on the performance of these burners in different pressures, temperatures, capacities, mixture velocities and equivalence ratios. The main design parameters of low swirl burners are the swirl number and the recess length. The objective of this paper is the investigation of recess length effects on the burner performance. A rig test has been established and utilized to study the effects of different equivalence ratios and recess lengths on the temperature distribution and flame regime of low swirl burners. Results revealed that increasing the recess length causes the increase in axial bulk velocity and hence the lifted flame would be stable in wider range of equivalence ratios. Observations also show the significant effect of the specific divergent flame regime of low swirl burners on result in uniform temperature distribution inside the combustion chamber and lower NOx production
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
191
204
http://jsfm.shahroodut.ac.ir/article_419_495fe2389b096ba64380b99a6126b8d0.pdf
dx.doi.org/10.22044/jsfm.2015.419
The Modeling of Cement Rotary Kiln Based on Spang Model for Investigation of CO2 Emission in Cement Production Process
Habibollah
Fateh Nobandegani
Msc. student of Mechanical engineering/Tarbiat modares university
author
Kiumars
Mazaheri
Professor in Mechanical engineering/Tarbiat modares university
author
text
article
2015
per
Cement rotary kilns are extensively used to change raw material into clinker. Complex phenomenon is observed in cement rotary kilns resulting from conduction, convection and radiation heat transfer, interactions between bed materials and hot gas flow and kiln rotation. Therefore, the modeling of cement rotary kiln have difficulty due to non-linear and stiff set of equations. Regards to over prediction of the maximum inner temperature of the kiln in Spang model; a one dimensional, steady state model is developed based on Spang model to investigate the operation of a cement kiln. In the present work, temperature distribution of hot gases is predicted using two-step methane kinetic to calculate the heat of combustion. Since the amount of CO2 emission in cement kiln processes is very important, CO2 emission generated by both bed material reactions and combustion process are calculated and compared. Modeling results showed that approximately half of CO2 emission is in result of combustion process and other one is from bed material reactions.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
205
216
http://jsfm.shahroodut.ac.ir/article_516_89d9cba8bca09d2a30a100de29d0d21d.pdf
dx.doi.org/10.22044/jsfm.2015.516
Numerical Investigation of Conjugate Natural Convection Heat Transfer in Porous Enclosure with Lattice Boltzmann Method
mohammadreza
rezaie
Department of Mechanical Engineering, Ferdowsi University, Mashhad, Iran
author
mohammad javad
maghrebi
استاد، دانشکده مهندسی مکانیک، دانشگاه فردوسی مشهد، مشهد
author
text
article
2015
per
In this study, the laminar conjugate natural convection inside a porous enclosure with two solid walls is studied numerically using the lattice Boltzmann method. The Porous media is simulated at the representative elementary volume scale. The Darcy–Brinkman–Forchheimer model is used to model the porous media in the range of 10-4
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
217
231
http://jsfm.shahroodut.ac.ir/article_525_a10fb03b4fb5303b38b0f5378f22631c.pdf
dx.doi.org/10.22044/jsfm.2015.525
Numerical Investigation of the Electric Field Effects on the Flow and Forced Convection Heat Transfer over a Backward-acing Step
Kamran
Mostajiri Abid
Mech. Eng., University of Guilan, Rasht, Iran
author
Nima
Amanifard
Dep. Mech. Eng., University of Guilan, Rasht, Iran
author
Hamed
Mohaddes Deylami
Faculty of Technology and Engineering, East of Guilan, University of Guilan, Rudsar, Iran
author
Farid
Dolati
Mech. Eng., University of Guilan, Rasht, Iran
author
text
article
2015
per
In this paper, the flow and temperature fields affected by electric field applied to the fine wire are numerically investigated for the incompressible, turbulent, and steady flow over a backward-facing step. The numerical modeling is based for solving electric, flow, and energy equations with the finite volume approach. The computed results are firstly compared with the experimental data in case of flat plate and the results agree very well. Then, the effect of different parameters such as the applied voltage, Reynolds number, and the emitting electrode position on the heat transfer coefficient and preesure drop is evaluated. The numerical results show that the heat transfer coefficient with the presence of electric field increases with the applied voltage but decreases when the Reynolds number are augmented. Moreover, reduction of distance between the emitting electrode and the step edge can significantly effect on the heat transfer enhancement and variations in pressure drop.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
233
248
http://jsfm.shahroodut.ac.ir/article_524_b3fb522f255a7724a05ab42eec011d7a.pdf
dx.doi.org/10.22044/jsfm.2015.524
Numerical Study of Solid Particle Deposition on a Square Filter Using Lattice Boltzmann Method
Amir
Sadeghi pour marvi
کارشناس ارشد مهندسی شیمی– محیط زیست،دانشکده فنی مهندسی، دانشگاه شهید باهنر کرمان
author
Ataallah
Soltani Goharrizi
استاد مهندسی شیمی، دانشکده فنی مهندسی، دانشگاه شهید باهنر کرمان
author
Saeed
Jafari
استادیار مهندسی نفت و گاز، دانشکده فنی مهندسی، دانشگاه شهید باهنر کرمان
author
text
article
2015
per
In this study, the motion of solid particles and fluid flow pattern around square cylinders is simulated. Two dimension Lattice Boltzmann method (LBM) is used to solve momentum and energy equation. To achieve this aim, first, the isothermal and nonisothermal fluid flow around obstacle is simulated by LBM; then, transport of the particles are evaluated while the equation of motion is employed. In this context, Lagrangian method is applied for simulating solid particles where the effect of particles on the flow is ignored. According to the obtained results, simulating the isothermal flow around the circular cylinder shows that with increasing Reynolds number decreased frequency of the flow. Also, investigating on nonisothermal flow around obstacle shows that with increasing blockage ratio, Nusselt number was increased. The results shows that with increasing Reynolds number deposition of small particles are increased, but deposition of large particles at low Reynolds number are better. Thermophoresis force is affected on particle smaller than 1µm and capture efficiency of particles was increased. Our results are good agreement with previous theoretical predictions and experimental observation.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
249
260
http://jsfm.shahroodut.ac.ir/article_421_4f94b00dd1613fa34974c4814372336c.pdf
dx.doi.org/10.22044/jsfm.2015.421
Investigation of Internal Flow of Binary Gas in a Rotating Cylinder Using Direct Simulation Monte-Carlo (DSMC)
J.
Khadem
استادیار، دانشکده مهندسی، دانشگاه بیرجند
author
A.
Abotalebi
کارشناس ارشد، دانشکده مهندسی، دانشگاه بیرجند
author
S.
Nourazar
Assoc. Prof., Mech. Eng., Amirkabir University of Technology, Tehran, Iran
author
text
article
2015
per
In this paper a rarefied binary gas mixture flow of Argon and Helium inside a rotating cylinder with constant angular velocity and constant wall temperature is investigated using the direct simulation of Monte - Carlo (DSMC) method. The number of different molecules were used, to study the dependence of the solution to number molecule model. The results show that increasing the number of molecules model is more accurate, but On the other hand increase the simulation time. Also for modeling the intermolecular collision, the variable soft sphere (VSS) and the variable hard sphere (VHS) were investigated in present work and the results were compared with each other. The results show that the variable soft sphere model (VSS) compared to the variable hard sphere model (VHS) for the temperature of the mixture near the cylinder walls more carefully. The analytical solution is also presented and compared with the current simulation results.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
261
270
http://jsfm.shahroodut.ac.ir/article_414_aa842bec718619fd9bbb83243f1f1669.pdf
dx.doi.org/10.22044/jsfm.2015.414
An Efficient Approach to Calculate the Amount of Released Gas in Branched Networks Considering Minor Loss Effects
M.
Behbahani Nezhad
university
author
A.
Azimi
استادیار، گروه مهندسی مکانیک، مرکز تحقیقات حفاری، دانشگاه شهید چمران، اهواز
author
H.
Saidian
کارشناس ارشد مکانیک، مرکز پژوهشی شبکه های گازرسانی، دانشگاه شهید چمران
author
M.
Changizian
استادیار، گروه مهندسی مکانیک،مرکز پژوهشی شبکههای گازرسانی، دانشگاه شهید چمران، اهواز
author
text
article
2015
per
In this paper, high velocity compressible flows in gas networks have been simulated in order to calculate the amount of released gas. The exact determination of the released gas in the networks needs to calculate the minor losses along with the existing compressibility effects. First, a new definition based on the physics of high velocity compressible flows has been proposed to calculate the minor losses. Then, different types of the three-dimensional flow through T-type junctions are simulated using Fluent Package. Based on the obtained results, an appropriate relation is proposed to calculate minor loss coefficients as function of junction inlet Mach number. The proposed relation has much simpler form than those proposed by the others and it can be more easily applied to develop the gas networks analysis softwares. Finally, the amount of released gas through a branched network is calculated using a new algorithm based on our proposed minor loss equation. The very good agreement between the numerical code and Fluent results shows the accuracy and efficiency of the proposed minor loss relation and applied numerical algorithm.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
271
284
http://jsfm.shahroodut.ac.ir/article_416_48c22e57c2712882e8ccd5dece08eef1.pdf
dx.doi.org/10.22044/jsfm.2015.416
Numerical Simulation of Wind Interference Effects Around a Group of Tall Buildings
M.
Hejazi
Professor / University of Isfahan
author
M. A.
Taghizadeh
کارشناس ارشد مهندسی سازه، گروه عمران، دانشکده فنی و مهندسی، دانشگاه اصفهان، اصفهان
author
E.
Afshari
استادیار گروه مهندسی مکانیک، دانشکده فنی و مهندسی، دانشگاه اصفهان، اصفهان
author
text
article
2015
per
Unlike a single building, determining the performance of two or more buildings next to each other under the effect of wind is very complex due to the inference effect. One of the latest efforts in investigating the interference effect is determining the interference factors and pressure coefficients of a group of tall buildings using Computational Fluid Dynamics. In this paper, the pressure coefficients and interference factors of a group of tall buildings with different heights placed at different distances due to various wind directions have been studied. The effect of buildings distances and direction of wind load on two groups of four tall buildings on the average pressure coefficients of the buildings in the group has been investigated. For the selected distances, in over 50% of cases by increasing the distance between the tall buildings the average pressure coefficients on buildings increase. In order to show the wind interference effects, the interference factors, i.e. the ratio of pressure coefficients on a building in a group of tall buildings to those of a single building, are calculated and compared. Interference factors show that the maximum and minimum pressure coefficients on a building in a group of tall buildings are up to three times of those of a single building.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
285
301
http://jsfm.shahroodut.ac.ir/article_529_9a9faf1aa9c6ba4d4fdd659eaafec792.pdf
dx.doi.org/10.22044/jsfm.2015.529
Exergy, Exergoeconomic & Environmental Impact Analysis and Multi-Objective Optimization of Damavand Combined Cycle Power Plant
M.
Ameri
دانشیار، دانشکده مهندسی مکانیک و انرژی، دانشگاه شهید بهشتی، تهران
author
H.
Mokhtari
M.Sc. Student, Mech. & Energy Eng. Dept., Shahid Beheshti Univ., Tehran, Iran
author
text
article
2015
per
In this paper, a combined cycle power plant (CCPP) was optimized based on three criteria. The first criterion which is for heat recovery steam generator (HRSG) considers the increase of the whole cycle exergy efficiency as an objective function. The exergy analysis has revealed that drum is a high temperature sensitive part of HRSG with high exergy destruction. Therefore, the second optimization criterion was based on the drum saturated temperature which caused the exergy destruction reduction of this component. The third optimization criterion was based on the cost reduction, the increase of the whole cycle exergy efficiency and the decrease of CO2 emission. To validate the results, the Damavand CCPP data has been used and the results have shown that the whole cycle optimization criterion yields better results in comparison with the other optimization criteria and it causes cost reduction (capital, environmental impacts and exergy destruction costs) as well as the increase of exergy efficiency. The value of CCPP decision parameters is highly dependent on the ambient temperature. Therefore, it is not possible to apply the same value for CCPP at various temperatures. The Genetic algorithm improved the cycle optimized parameters with respect two objectives of CO2 emission and power plant costs reduction.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
303
328
http://jsfm.shahroodut.ac.ir/article_415_cb8bbd497fce9c04b81046f77f7eb460.pdf
dx.doi.org/10.22044/jsfm.2015.415
The Unsteady Behavior of the Natural Convection Heat Transfer in a Square Enclosure by 90° Rotate
R.
Rabani
Yazd university
author
Sh.
Talebi
استادیار مهندسی مکانیک، دانشگاه یزد، یزد
author
text
article
2015
per
The natural convection heat transfer in a square enclosure depends on the geometry of the enclosure, the amount and the type of heating and cooling on the hot and cold walls, the fluid proprieties and the inclination angle of the enclosure. In this paper, the natural convection in a square enclosure with two hot and cold vertical walls and two adiabatic horizontal walls is investigated. This vertical enclosure by rotating 90° changes into a horizontal enclosure. The aim of this study is to investigate the time dependent behavior of the flow and the heat transfer through it affected by the inclination angle. The lattice Boltzmann method for numerical simulation of the fluid flow and the heat transfer is used. The problem is solved by five values of rotation times for Rayleigh number 105. Streamlines, temperature distribution and the amount of heat transfer in every time obtained. The results show that by the fast rotation major changes in the temperature distribution and the heat transfer occurs after the stopping of rotation. But in the slow rotation the amount of heat transfer is very close to the steady state in any time at the same situation.
Journal of Solid and Fluid Mechanics
Shahrood University of Technology
2251-9475
5
v.
2
no.
2015
329
339
http://jsfm.shahroodut.ac.ir/article_530_282e54068231ce3cfb79c839e3ea5a74.pdf
dx.doi.org/10.22044/jsfm.2015.530