2014
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Investigation of shell and tube heat exchangers by using a design of experiment
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Heat exchangers are one of the most important devices of mechanical systems in modernsociety. Most industrial processes involve the transfer of heat and more often they requirethe heat transfer process to be controlled. A heat exchanger is the heat exchanged betweentwo media, one being cold and the other being hot. There are different types of heatexchanger, but the type which is widely used in industrial application is the shell and tube.In this study, experiments conducted based on fully replicable fivefactor, fivelevel centralcomposite design. Regression modelsare developed to analyse the effects of shell and tubeheat exchange process parameter such as inlet temperature of hot fluid and flow rates ofcold and hot fluid. The output parameters of a heat exchanger are used for analysing thedirect and interactive effects of heat exchange process parameters.
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59
66


S.
Balamurugan
Department of Mechanical Engineering, Coimbatore Institute of Technology, Coimbatore – 641 014, Tamilnadu, INDIA.
Department of Mechanical Engineering, Coimbatore
India


D.P.
Samsoloman
Department of Mechanical Engineering, Coimbatore Institute of Technology, Coimbatore – 641 014, Tamilnadu, INDIA.
Department of Mechanical Engineering, Coimbatore
India
Shell and Tube Heat
Exchanger
DOE
Experiment
[[1]. Y. Ozcelik, Exergetic optimization of shell and tube heat exchangers using genetic based algorithm, Appl. Therm. Eng., vol. 27, pp. 1849 1856, (2007). ##[2]. P. Vijaysai, M.D. Osborn, S.S. Au, K. Ravi Chandra Reddy, Prediction of performance assessment of heat exchangers for proactive remediation, IEEE trans, 30553060,(2006) ##[3]. Q. Wang, G. Xie, M. Zeng and L. Luo, Prediction of heat transfer rates for shell and tube heat exchangers by artificial neural networks approach, J. Therm. Sci., vol.15, no.3, pp. 257262,(2006).##]
Magnetohydrodynamic mixed convection effects on the removal process of fluid particles from an open cavity in a horizontal channel
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2
This paper presents the results of a numerical study on the heat transfer performance and the removal process of fluid particles under the influence of magnetohydrodynamic mixed convection in a horizontal channel with an open cavity. The bottom wall of the cavity is heated at a constant temperature (Th) while the top wall of the channel is maintained at a relatively low temperature (Tc). Air with a uniform velocity (u0) and temperature (Tc) is introduced to the channel. The analysis is carried out for a range of values of the Grashof number (103≤Gr≤106), the Reynolds number (1≤Re≤100), and the Hartmann number (0≤Ha≤100).The results show that the heat transfer rate increases as the Grashof number increases and decreases as the Reynolds and Hartmann numbers increase. It is also shown that the removal process accelerates as the Grashof number increases and, however, decelerates as the Reynolds and Hartmann numbers increase.
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67
74


Rouhollah Yadollahi
Farsani
Associate Lecturer, Ardal Center, Shahrekord branch, Islamic Azad University, Shahrekord, Iran
Associate Lecturer, Ardal Center, Shahrekord
Iran(Islamic Republic of Iran)


Behzad
Ghasemi
Chemical Engineering Professor, Engineering Faculty, Shahrekord University, Shahrekord, Iran
Chemical Engineering Professor, Engineering
Iran(Islamic Republic of Iran)
behzadgh@yahoo.com


Saiied Mostafa
Aminossadati
Senior Lecturer, School of Mechanical and Mining Engineering, the University of Queensland, QLD 4072, Australia
Senior Lecturer, School of Mechanical and
Iran(Islamic Republic of Iran)
uqsamino@uq.edu.au
Magnetohydrodynamic
Mixed convection
Channel
Fluid particles
Removal process
[[1]. L. C.Fang, "Effect of mixed convection on transient hydrodynamic removal of a contaminant from a cavity," International Journal of Heat and Mass Transfer, 46(11) 20392049, (2003). ##[2]. L. C.Fang, "Effect of duct velocity profile and buoyancyinduced flow on efficiency of transient hydrodynamic removal of a contaminant from a cavity," International Journal for Numerical Methods in Fluids, 44(12),13891404, (2004). ##[3]. N. M.Brown, and F. C.Lai, "Correlations for combined heat and mass transfer from an open cavity in a horizontal channel," International Communications in Heat and Mass Transfer, 32(8),10001008, (2005). ##[4]. B. Premachandran, and C.Balaji, "Mixed convection heat transfer from a horizontal channel with protruding heat sources," Heat and Mass Transfer/Waerme und Stoffuebertragung, 41(6), 510518, (2005). ##[5]. I. A.Ermolaev, and A. I.Zhbanov, "Mixed convection in a horizontal channel with local heating from below," Fluid Dynamics, 39(1) 2935,(2004). ##[6]. J. C.Leong, N. M.Brown, and F. C.Lai, "Mixed convection from an open cavity in a horizontal channel," International Communications in Heat and Mass Transfer, 32(5), 583592, (2005). ##[7]. S. M. Aminossadati, and B. Ghasemi, "A numerical study of mixed convection in a horizontal channel with a discrete heat source in an open cavity," European Journal of Mechanics, B/Fluids, 28(4), 590598,(2009). ##[8]. J. P.Garandet, T.Alboussiere, and R.Moreau, "Buoyancy driven convection in a rectangular enclosure with a transverse magnetic field," International Journal of Heat and Mass Transfer, 35(4), 741748,(1992). ##[9]. S. Alchaar, P.Vasseur, and E.Bilgen, "Natural convection heat transfer in a rectangular enclosure with a transverse magnetic field," Journal of Heat Transfer, 117(3), 668673,(1995). ##[10]. N.Rudraiah, R. M. Barron, M.Venkatachalappa, and C. K.Subbaraya, "Effect of a magnetic field on free convection in a rectangular enclosure," International Journal of Engineering Science, 33(8), 10751084, (1995). ##[11]. B.Ghasemi, S. M.Aminossadati, and A.Raisi, "Magnetic field effect on natural convection in a nanofluidfilled square enclosure," International Journal of Thermal Sciences, 50(9), 17481756,(2011). ##[12]. R.Siegel, "Effect of magnetic field on forced convection heat transfer in a parallel plate channel," Journal of Applied Mechanics, 25, 41516, (1987). ##[13]. L. H. Back, "Laminar heat transfer in electrically conducting fluids flowing in parallel plate channels," International Journal of Heat and Mass Transfer, 11(11), 16211636,(1968). ##[14]. R. A. Alpher, "Heat transfer in magnetohydrodynamic flow between parallel plates," International Journal of Heat and Mass Transfer, 3(2),108112,(1961). ##[15]. T.Sawada, T.Tanahashi, and T.Ando, "Twodimensional flow of magnetic fluid between two parallel plates," Journal of Magnetism and Magnetic Materials, 65(2), 327329,(1987) ##[16]. H. A.Attia, "Transient MHD flow and heat transfer between two parallel plates with temperature dependent viscosity," Mechanics Research Communications, 26(1), 115121,(1999). ##[17]. S.Mahmud, S. H.Tasnim, and M. A. H. Mamun, "Thermodynamic analysis of mixed convection in a channel with transverse hydromagnetic effect," International Journal of Thermal Sciences, 42(8), 731740, (2003). ##[18]. P.R. Nath, P. M. V.Prasad, and D. R. V.PrasadaRao, "Computational hydromagnetic mixed convective heat and mass transfer through a porous medium in a nonuniformly heated vertical channel with heat sources and dissipation," Computers and Mathematics with Applications, 59(2), 803811, (2010). ##[19]. M. M.Rahman, S.Parvin, R.Saidur, and N. A.Rahim, "Magnetohydrodynamic mixed convection in a horizontal channel with an open cavity," International Communications in Heat and Mass Transfer, 38(2), 184193, (2011). ##[20]. S. V. Patankar, "Numerical heat transfer and fluid flow," Hemisphere Publishing Corporation, Taylor and Francis Group, New York, 113137, (1980). ##[21]. S. McKee, M. F.Tome, V. G. Ferreira, J. A.Cuminato, A.Castelo, F. S.Sousa, and N.Mangiavacchi, "THE MAC method," Computers and Fluids, 37, 907930, (2008). ##F. H. Harlow, and J. E.Welch, "Numerical calculation of timedependent viscous incompressible flow of fluid with free surface," Physics of Fluids, 8(12), 21822189, (1965).##]
The effect of Geometrical parameters on heat transfer coefficient in helical double tube exchangers
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Helical coil heat exchangers are widely used in industrial applications ranging fromcryogenic processes, airconditioning, and nuclear reactors to waste heat recovery due totheir compact size and high heat transfer coefficient. In this kind of heat exchangers, flowand heat transfer are complicated. This paper reports a numerical investigation of theinfluence of different parameters such as coil radius, coil pitch and diameter of tubeon the characteristics of heat transfer in helical double tube heat exchangers usingthe wellknown Fluent CFD software. Modeling of the study was implemented based onprinciples of heat transfer, fluid mechanics, and thermodynamics. By imposing boundaryconditions and selecting of an appropriate grid, whereby the results are independent ofmeshing, the obtained results were compared and validated with existing experimentalresults in the open literature. The results indicate that heat transfer augments by increasingof the inner Dean number, inner tube diameter, curvature ratio, and by the reduction of thepitch of the heat exchanger coil.
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82


Seyed Faramarz
Ranjbar
Mechanical Engineering Faculty, University of Tabriz, Tabriz, Iran
Mechanical Engineering Faculty, University
Iran(Islamic Republic of Iran)


Mir Hatef
Seyyedvalilu
Mechanical Engineering Faculty, University of Tabriz, Tabriz, Iran
Mechanical Engineering Faculty, University
Iran(Islamic Republic of Iran)
s.hatef90@ms.tabrizu.ac.ir
Helical double tube
Heat exchanger
Curvature ratio
Dean number
Overall heat transfer coefficient
[[1]. Rennie T.J, Raghavan G.S.V. Laminar parallel flow in a tubeintube helical heat exchange; AIC2002 Meeting CSAE/SCGR Program, Saskatchwan.1417; 2002. ##[2]. Yadav Y.P. and Tiwari G.N. Transient analysis of doublepipe heat exchanger coupled to flatplate solar collector; Energy conversion and management volume 27, 1519, 1987. ##[3]. Rennie T.J, Raghavan G.S.V. Experimental studies of a double pipe helical heat exchanger; Experimental Thermal and Fluid Science, 919924, 2005. ##[4]. Rennie T.J, Raghavan G.S.V. Effect of fluid thermal properties on the heat transfer characteristics in a doublepipe helical heat exchanger; I.J. of Thermal Sciences, volume 45, 11581165, 2006. ##[5]. Han J. T, Lin C. X, Ebadian M. A. Condensation heat transfer and pressure drop characteristics of R134a in an annular helical pipe; International communications in heat and mass transfer, volume 32, 13071316, 2005. ##[6]. Kumar V, Saini S, Sharma M, Nigam K. D. P. Pressure drop and heat transfer study in tubeintube helical heat exchanger; Chemical Engineering Science, volume61, 44034416, 2006. ##[7]. Lin C. X, Ebadian M. A. Condensation heat transfer and pressure drop of R134a in annular helicoidal pipe at different orientations; International Journal of Heat and Mass Transfer, Volume50, 42564264, 2007. ##[8]. Kumar V, Faizee B, Mridha M, Nigam K. D. P. Numerical studies of a tubeintube helically coiled heat exchanger; Chemical Engineering and Processing, volume 47,22872295, 2008. ##[9]. Garrido D. C, Castelazo E. S, Hernandez J.A, Valladares O. G. Siqueiros J. Romero D.J. Heat transfer of a helical doublepipe a vertical evaporator; Theoretical Analysis &Experimental validation, App. Energy, 2008. ##[10]. Xiaowen Yi, Lee W.L. The use of helical heat exchanger for heat recovery domestic watercooled airconditioner; Energy conversion and management, volume50, 240246, 2009. ##[11]. Xin RC, Awwad A, Dong Z.F, Ebadian M. A. An Experimental study of singlephase and twophase flow pressure drops in annular helicoidal pipes; International Journal of Heat and Fluid Flow, Volume18, 482488, 1997. ##[12]. Petrakis M. A., Karahalios G. T. Exponentially decaying flow in a gently curved annular pipe; International Journal of Nonelinear Mechanics, 823835, 1997. ##[13]. Petrakis M. A., Karahalios G. T. Fluid flow behavior in a curved annular conduit; International Journal of Nonelinear Mechanics, Volume 34, 1325, 1999. ##[14]. Han J. T, Lin C.X, Ebadian M. A. Condensation heat transfer and pressure drop characteristics of R134a in an annular helical pipe; International Communications in Heat & Mass Transfer, volume 32, 13071316, 2005. ##[15]. Reza Beigzadeh, Masoud Rahimi. Prediction of heat transfer and flow characteristics in helically coiled tubes using artificial neural networks; International Communications in Heat and Mass Transfer, volume 32, 1279–1285, 2012. ##[16]. Massimiliano Di Liberto, Michele Ciofalo. A study of turbulent heat transfer in curved pipes by numerical simulation; International Journal of Heat and Mass Transfer, 112–125, 2013. ##[17]. Gabriela Huminic, Angel Huminic. Heat transfer characteristics in double tube helical heat exchangers using nanofluids; International Journal of Heat and Mass Transfer, 4280–4287, 2011. ##[18]. P.S. Srinivasan. Pressure drop and heat transfer in coils; Chemical Engineering, 113119, 1968. ##[19]. B. Xavier, T. Xavier, P. philippe, B. Philippe. Comparison of tetrahedral and hexahedral meshe for organ finite element modeling: an application to kidney impact. ##[20]. Jayakumar J. S, Mahajani S. M, Mandal J. C, Vijayan P. K, Bhoi R. Experimental and CFD estimation of heat transfer in helically coiled heat exchangers. Chemical Engineering Research and Design; 86:221232, 2008. ##]
Numerical modelling of doublediffusive natural convection within an arc shaped enclosure filled with a porous medium
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Numerical study of doublediffusive natural convective heat transfer in a curved cavity filledwith a porous medium has been carried out in the current study. Polar system has beenselected as coordinate system. As a result, all equations have been discredited in r and θdirections. Brinkmann extended Darcy model has been utilized to express fluid flow inporous matrix in the enclosure. Smaller and larger curved walls are supposed to be hot andcold sources, respectively. Other two walls are insulated. The numerical solution has beenobtained based on the finite volume methodology via staggered grid system, which will beexplained in detail in its respective section. Finally, at the result section the effects of allpertinent parameters i.e. Grashof number, Lewis number, Darcy number, and Buoyancy ratioon the fluid motion and medium thermal behavior have been illustratively discussed. Resultsreveal that an increasing in Lewis number has a negative effect on heat transfer, while it hasa positive impact on mass transfer. It is also seen that the flow intensity is increased bydecreasing Lewis number. In addition, it is observed that for the aiding flow case, averageNu and Sh numbers decrease with increasing buoyancy ratio, while for opposing flow casesNu and Sh augment with decreasing buoyancy ratio.
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83
91


Ariyan
Zare Ghadi
Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
Faculty of Mechanical Engineering, Semnan
Iran(Islamic Republic of Iran)
azghadi@semnan.ac.ir


Ali
Haghighi Asl
Faculty of Chemical Engineering, Semnan University, Semnan, Iran
Faculty of Chemical Engineering, Semnan University
Iran(Islamic Republic of Iran)
ahaghighi@semnan.ac.ir


Mohammad Sadegh
Valipour
Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
Faculty of Mechanical Engineering, Semnan
Iran(Islamic Republic of Iran)
msvalipour@semnan.ac.ir
FVM method
Doublediffusive convection
Arcshaped cavity
Porous media
[[1]. C.Y. Hu, M.M. ELWakil, Simultaneous heat and mass transfer in a rectangular cavity, Proceeding of International Heat Transfer Conference 5 (1974) 2428. ##[2]. S. Ostrach, Natural convection with combined driving forces, Physico Chemical Hydrodynamics 1 (1980) 233247. ##[3]. S.Ostrach, Natural convection heat transfer in cavities and cells, 7th International Heat Transfer Conference 1 (1983) 365379. ##[4]. S. Ostrach, Fluid mechanics in crystal growththe 1982 freeman scholar lecture, Journal of Fluid Engineering 105 (1983) 520. ##[5]. T.S. Lee, P.G. Parikh, A. Acrivos, D. Bershader, Natural convection in a vertical channel with opposing buoyancy forces, International Journal of Heat and Mass Transfer 25 (1982) 499511. ##[6]. P. Nithiarasu, T. Sundararajan, K.N. Seetharamu, Doublediffusive natural convection in a fluid saturated porous cavity with a freely convecting wall, International Communications in Heat and Mass Transfer 24 (8) (1997) 1121–1130. ##[7]. V.A.F. Costa,Doublediffusive natural convection in parallelogrammic enclosures filled with fluid saturated porous media, International Journal of Heat and Mass Transfer 47 (2004) 2699–2714 ##[8]. B.Goyeau, J.P. Songbe and D. Gobin, Numerical study of doublediffusive natural convection in a porous cavity using the Darcybrinkman formulation, International Journal of Heat and Mass Transfer, 39 (7) (1996), 13631378. ##[9]. A.J. Chamkha, A. AlMudhaf, Doublediffusive natural convection in inclined porous cavities with various aspect ratios and temperaturedependent heat source or sink, Heat and Mass Transfer/Waerme und Stoffuebertragung 44 (6) (2008) 679–693. ##[10]. J.T. Vander Der Eyden, TH. H. Van Der Meer, K. Hanjalic, E. Biezen, J. Bruining, Doublediffusive natural convection in trapezoidal enclosuresm International Journal of Heat and Mass transfer, 41 (13) (1998), 18851898. ##[11]. M. Bourich, M. Hasnaoui, A. Amahmid, Doublediffusive natural convection in a porous enclosure partially heated from below and differentially salted, International Journal of Heat and Fluid Flow 25 (2004) 1034–1046. ##[12]. M.A. Teamah, M.M.Khairat Dawood, M. ElMaghlany, Doublediffusive natural convection in a square cavity with segmental heat sources, European Journal of Scientific Research, 54 (2) (2011), 287301. ##[13]. R. El Ayachi, A. Raji, M. Hasnaoui, A. Abdelbaki, M. Naimi, Resonance of doublediffusive convection in a porous medium heated with a sinusoidal exciting temperature, Journal of Applied fluid Mechanics, 3 (2) (2010), 4352. ##[14]. M. Bourich, A. Amahmid, M. Hasnaoui, Doublediffusive convection in a porous enclosure submitted to cross gradients of temperature and concentration, Energy Conversion and Management, 45 (2004), 1655–1670. ##[15]. M.A. Teamah, Doublediffusive laminar natural convection in a symmetrical trapezoidal enclosure, Alexandria Engineering Journal, 45 (3) (2006), 251263. ##[16]. A. Belazizia, S. Benissaad, S. Abboudi, Doublediffusion natural convection of binary fluid in a square enclosure with top Active vertical wall, Advances in Theoretical and Applied Mechanics, 5 (3) (2012), 119131. ##[17]. R. Nikbakhti, A. rahimi, Doublediffusive natural convection in a rectangular cavity with partially thermally active side walls, Journal of the Taiwan Institute of Chemical Engineers 43 (2012) 535–541. ##[18]. M.S.Valipour, A.Z. Ghadi, Numerical investigation of fluid flow and heat transfer around a solid circular cylinder utilizing nanofluid, International communications in heat and mass transfer, 38 (2011), 12961304. ##[19]. S.V. Patankar, Numerical Heat Transfer and Fluid Flow, Hemisphere Publishing Corporation, Washington, 1980. ##[20]. H.K. Versteeg, W. Malalasekera, An introduction to computational fluid dynamics. The finite volume method, John Wiley & Sons Inc, New York, 1995. ##[21]. R. Iwatsu, J.M. Hyun, K. Kuwahara, Mixed convection in a driven cavity with a stable vertical temperature gradient, International Journal of Heat and Mass Transfer 36 (1993) 16011608.##]
Numerical simulation of turbulent compressible flows in a CD nozzle with different divergence angles
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2
Compressible gas flow inside a convergentdivergent nozzle and its exhaust plume atdifferent nozzle pressure ratios (NPR) have been numerically studied with severalturbulence models. The numerical results reveal that, the SST k–ω model give the bestresults compared with other models in time and accuracy. The effect of changes in value ofdivergence halfangle (ε ) on the nozzle performance, thrust coefficient ( Cf ) anddischarge coefficient ( C d) has been investigated numerically. The predicted results showthat for a given divergence angle, the thrust coefficient (Cf ) increases by increasing nozzlepressure ratio. Also, for a given nozzle pressure ratio, the thrust coefficient increases as thenozzle divergence angle decreases. When the CD nozzle is chocking, the value of dischargecoefficient is independent of nozzle pressure ratio and also for a given nozzle pressure ratio,the discharge coefficient increases as the divergence nozzle angle (ε) increases.
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93
100


Mohammad Hadi
Hamedi Estakhrsar
MalekAshtar University of Technology, Tehran, Iran.
MalekAshtar University of Technology, Tehran,
Iran(Islamic Republic of Iran)
hadihamedi20@gmail.com


Mehdi
Jahromi
MalekAshtar University of Technology, Tehran, Iran
MalekAshtar University of Technology, Tehran,
Iran(Islamic Republic of Iran)
jahromi@iust.ac.ir
Numerical Simulation
convergingdiverging nozzle
Divergence angle
Thrust coefficient
Discharge coefficient
Static temperature
[[1]. K. K. Quintao, Design Optimization of Nozzle Shapes for Maximum Uniformity of Exit Flow,Florida International University,M.S. Thesis, (2012). ##[2]. A. M. Geatz, A Prediction Code for the Thrust Performance of Two Dimensional, NonAxisymmetric, Converging Diverging Nozzles,Air Force Institute of Technology,PH.D Thesis, (2005). ##[3]. Q. Xiao, H.M. Tsai , D. Papamoschou, Numerical Study of Jet Plume Instability from an Overexpanded Nozzle, 45th AIAA Aerospace Sciences Meeting and Exhibit, Nevada, AIAA, (2007). ##[4]. A.Hamed,C.Vogiatzist, Overexpanded TwoDimensional ConvergentDivergent Nozzle Performance, Effects of ThreeDimensional Flow Interactions, Journal ofPropulsion and Power,14, 234240, (1998). ##[5]. A.Hamed, C.Vogiatzist, ThreeDimensional Flow Computations and Thrust Predictions in 2DCD Overexpanded Nozzles, AIAA paper 970030, (1997). ##[6]. A. Balabel, A.M. Hegab, S. Wilson, M. Nasr, S. ElBehery, Numerical Simulation of Turbulent Gas Flow in a Solid Rocket Motor Nozzle, 13th International Conference on Aerospace Science and Aviation Technology, Egypt, (2009). ##[7]. N. J. Georgiadis, D. Papamoschou, Computational Investigation of HighSpeed Dual Stream Jets, AIAA 20033311, (2003). ##[8]. C. F.Chenault, P.Beran, Numerical Investigation of Supersonic Injection Using a ReynoldsStress Turbulence Model, AIAA Journal, 37, 12571269, (1999). ##[9]. H.Zhang, R.So, T.Gatski, C. Speziale, a NearWall SecondOrder Closure for Compressible Turbulent Flows, NearWall Turbulent Flows, edited by R. So, C. Speziale, and B. Launder, Elsevier, New York, 209218,(1993). ##[10]. M.A. Dembowski, N.J. Georgiadis, an Evaluation of Parameters Influencing Jet Mixing Using the WIND NavierStokes Codes, NASA/TM211727,(2002). ##[11]. K. A. Park, Y. M. Choi, H. M. Choi, T. S. Cha, B.H. Yoon,The Evaluation of Critical Pressure Ratios of Sonic Nozzles at Low Reynolds Numbers. Flow Measure, Instrum,12, 37–41, (2001). ##[12]. J. S. Paik, K. A. Park, J. T. Park, InterLaboratory Comparison of Sonic Nozzles atKRISS,Flow Measure, Instrum, 11, 339–344, (2000). ##[13]. R. A. Ahmad, Discharge Coefficients and Heat Transfer for Axisymmetric Supersonic Nozzles. Heat Transfer Eng, 22, 40–61, (2001). ##[14]. H. D. Kim, J. H. Kim, K. A. Park, T.Setoguchi, S. Matsuo, Computational Study of the Gas Flow Through a Critical Nozzle. Proc. Instn. Mech. Engrs, 217, 1179–1189, (2003). ##[15]. A. Balabel, A.M. Hegab, M. Nasr, Samy M. ElBehery, Assessment of Turbulence Modeling for Gas Flow in TwoDimensional Convergent–Divergent Rocket Nozzle, Applied Mathematical Modelling, 35, 3408–3422, (2011). ##[16]. V.S,Krishnamurty, W.Shyy, Effect of Wall Roughness on the Flow through ConvergingDiverging Nozzles, Journal of Propulsion and Power, 13, 753762, (1997). ##[17]. M.L. Mason, L.E. Putnam,J.R. Richard, The Effect of Throat Contouring on Two Dimensional ConvergingDiverging Nozzles at Static Condition, NASA Technical Paper 1704, (1980). ##[18]. Fluent, User’s Guide Fluent 6.3.26, Fluent Incorporated, Lebanon, NH, (2006). ##[19]. B. E. Launder, G. J. Reece, and W. Rodi, Progress in the Development of aReynoldsStress Turbulence Closure, J. Fluid Mech., 68, 537566, (1975). ##[20]. B. E. Launder, D. B. Spalding, Mathematical Models of Turbulence, AcademicLondon, 169189, (1972). ##[21]. F. R.Menter, TwoEquation EddyViscosity Turbulence Models for Engineering Applications, AIAA journal, 32, 15981605, (1994).##]
Removal of copper ions from aqueous solutions using polypyrrole and its nanocomposites
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2
In this article, preparation of polypyrrole and its nanocomposites as adsorbents werediscussed and the capability of separation of copper ions from aqueous solution were studied.Polypyrrole was prepared by chemical oxidative polymerization method of pyrrole usingFeCl3 as an oxidant. The removal of Cu (II) was investigated using PPy, PPy/TiO2 andPPy/TiO2/DHSNa nanocomposites. The products were investigated in terms of morphologyand chemical structure with scanning electron microscopy (SEM) and Fouriertransforminfrared spectroscopy (FTIR). Batch studies were performed to evaluate the influence ofvarious experimental parameters such as pH, ion dosage and contact time. Optimumconditions for copper ions removal were found to be pH 3, ion dosage of 50 mg L1 and theequilibrium time equals to 30 minutes. It was also found that the equilibrium adsorptionisotherm was better described by Freundlich adsorption isotherm model.
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101
106


Somayeh
Nobahar
School of Chemical, Petroleum, and Gas Engineering, Semnan University,Semnan, Iran.
School of Chemical, Petroleum, and Gas Engineering
Iran(Islamic Republic of Iran)
somayenobahar@yahoo.com


Mehdi
Parvini
School of Chemical, Petroleum, and Gas Engineering, Semnan University,Semnan, Iran.
School of Chemical, Petroleum, and Gas Engineering
Iran(Islamic Republic of Iran)
m.parvini@sun.semnan.ac.ir


Hossein
Eisazadeh
Chemical Engineering Department, Shomal University, Amol, Iran.
Chemical Engineering Department, Shomal University
Iran(Islamic Republic of Iran)
eisazadeh@hotmail.com
Polypyrrole
Nanocomposite
Morphology
Cu (II) removal
[[1]. D. Klassen, Casarett and Doull's toxicology, The Basic Science of Poisons, 6th ed, McGrawHill, New York,(1996). ##[2]. Z.Zulfadhly, M.D.Mashitah, S. Bhatia, Heavy metals removal in fixedbed column by the macro fungus Pycnoporussanguineus, Environmental Pollution, 112(3), 463470, (2001). ##[3]. D.C.K. Ko,J.F. Porter, G. McKay,Optimised correlations for the fixedbed adsorption of metal ions on bone char,Chemical engineering science, 55(23), 5819–5829, (2000). ##[4]. S.Hena, Removal of chromium hexavalent ion from aqueous solutions using biopolymer chitosancoated with poly 3methyl thiophene polymer, Journal of Hazardous Materials, 181, 474–479, (2010). ##[5]. B. Scrosati, Conducting polymers: advanced materials for new design, rechargeable lithium batteries, Polymer International, 47, 5055, (1998). ##[6]. H. Eisazadeh, G. Spinks,G.G. Wallace,Conductive electroactive paint containing polypyrrole colloids,Mater. Forum, 17, 241245, (1993). ##[7]. V. Misoska, J. Ding, J.M. Davey, W.E. Price, S.F. Ralph, G. G. Wallace, Polypyrrole membranes containing chelating ligands: synthesis, characterisation and transport studies, Polymer 42 (21), 85718579, (2001). ##[8]. E.H.L. Falcao, W.M. de Azevedo, Polyanilinepolyvinyl alcohol composite as an optical recording material,Synthetic Metals, 128, 149154, (2002). ##[9]. N. Guernion,R.J. Ewen,K. Pihlainen, N.M. Ratcliffe,G. C. Teare, The fabrication and characterization of a highly sensitive polypyrrole sensors and its electrical responses to amines of differing basicity at high humidities Synthetic Metals, 126, 301310, (2002). ##[10]. H. Yamato, T.Koshiba, M.Ohwa, W. Wernet, M. Matsumura, A new method for dispersing palladium microparticles in conducting polymer films and its application to biosensors,Synthetic Metals, 87, 231236, (1997). ##[11]. S.K. Dhawan, N. Singh, S.Venkatachalam,Shielding effectiveness of conducting polyaniline coated fabrics at 101 GHz. Synthetic Metals, 125, 389393, (2002). ##[12]. S. Benabderrahmane, S. Bousalem, C. Mangeney, A. Azioune, M. J.Vaulay, M. M. Chehimi,Interfacial physicochemical properties of functionalized conducting polypyrrole particles, Polymer, 46, 13391346, (2005). ##[13]. H. Eisazadeh, Removal of chromium from waste water using polyaniline, Journal of applied polymers, 104, 19641967, (2007). ##[14]. H. Eisazadeh, Removal of Arsenic in Water Using Polypyrrole and Its Composites, Applied Science Journal, 3 (1), 1013, (2008). ##[15]. H. Eisazadeh, B.G. Bistouni, J. Korean,Preparation and characterization of aniline/acrylonitrile nanocomposites using various surfactants in aqueous media, Korean Journal of Chemical Engineering, 28(1), 287292, (2011). ##[16]. Y.D. Kim, I.C. Song, Electrorheological and dielectric properties of polypyrrole dispersions,Journal of Materials Science . 37, 50515055, (2002). ##[17]. M. Ferenets, A. 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Investigation of the thermohydraulic behavior of the fluid flow over a square ribbed channel
2
2
The thermohydraulic behavior of the air flow over a two dimensional ribbed channel wasnumerically investigated in various ribwidth ratio configurations (B/H=0.51.75) atdifferent Reynolds numbers, ranging from 6000 to 18000. The capability of differentturbulence models, including standard kε, RNG kε, standard kω, and SST kω, inpredicting the heat transfer rate was compared with the experimental results and it wasshowed that the kε turbulent models best adapt with the measured data. Four mainparameters, namely, the Nusselt number, friction factor, skin friction factor, and the thermalenhancement factor were examined through the simulations. Results indicate that anincrease in the Reynolds number caused the Nusselt number to increase and the frictionfactor to drop. It was found that the thermal enhancement factor augmented by an increasein the Reynolds number, and also, for a wider rib, i.e. at the higher the B/H ratio, a lowerthermal enhancement factor was obtained.
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Ali
Sarreshtedari
School of Mechanical
Engineering, University of Shahrood, Shahrood, Semnan, Iran.
School of Mechanical
Engineering, University
Iran(Islamic Republic of Iran)
sarreshtehdari@gmail.com


Alireza
Zamani Aghaee
School of Mechanical
Engineering, University of Shahrood, Shahrood, Semnan, Iran.
School of Mechanical
Engineering, University
Iran(Islamic Republic of Iran)
Turbulent flow
Ribbed channel
Heat transfer
pressure drop
Thermalenhancement
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