Iranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401Dynamic Simulation and Control of Microbial Cell Population in Continuous Bioreactors31610199ENA.R.EhsaniSchool of Chemical Engineering, Iran University of Science and Technology, Tehran, IranA.GhaemiSchool of Chemical Engineering, Iran University of Science and Technology, Tehran, Iran0000-0003-0390-4083Journal Article20150727Continuous bioreactors are critical unit operations in a wide variety of biotechnological processes. Due to the level of detail built in their mathematical formulation, cell population balance models represent the most accurate way of describing the microbial population heterogeneity in continuous bioreactor. In this work,the equation set of the model was solved numerically using rigorous'space–time conservation element and solution element' CE/SE method.MATLAB/Simulink pre-existing blocks are used for modeling and control of the different moments of cell mass distribution in a continuous bioreactor. For investigating the efficiency of automatic controller, 10% increase in maximum specific growth rate in Ks, was considered. The set point for zeroth, first and second moments of distribution were taken to be; M0,sp =0.6706 , M1,sp =0.1541 , M2,sp =0.0505, which correspond to a dilution rate of 0.953 h -1 and 0.6 h -1 . In the first case the controller response after 10 hours was (0.92 h -1 ± .05), (0.87 h -1 ± 0.4) and (0.92 h -1 ± 0.2). For the second case the controller response was close to set point(0.6 h -1 ± .001) after 20 hours.https://www.ijche.com/article_10199_0237a65a5396a6e4a6da6e1308ccc4e0.pdfIranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401Determination of Nusselt Number of Herschel Bulkley Nanofluids by Using CMA-ES Algorithm172810200ENM.Esmaeilizadeh DavaniDepartment of Chemical Engineering, Faculty of Engineering, Quchan University of
Advanced Technology, Quchan, IranJ.Mohebbi Najm AbadDepartment of Computer Engineering, Quchan Branch, Islamic Azad University, Quchan, IranR.MollaabbasiDepartment of Chemical Engineering, Faculty of Engineering, Quchan University of
Advanced Technology, Quchan, IranJournal Article20150727Drilling muds are the most applicable fluids in drilling. Two basic types of drilling fluids are used, water based muds (WBM) and oil based muds (OBM). Water based muds are more applicable than oil based muds. One of the most important applications of this fluid is cooling a bit. Chemical engineers try to change drilling mud‘s rheological property in order to increase heat transfer to the bit. Rheological properties of drilling muds are well described by the Herschel Bulkley model. Adding polyacrylic acid to water changes its rheological property to Herschel Bulkley fluid. Standard<br />equations like Shah and London and Hausen correlations were not able to predict local Nusselt number of non-Newtonian fluids.This study concerns estimating parameters of a local Nusselt number of Herschel Bulkley fluids with CuO nanoparticles in four concentrations of 0.1, 0.3, 0.6 and 0.05% in constant heat flux and laminar region. A<br />nonlinear optimization algorithm (CMA-ES) was used to estimate local Nusselt number. There is good agreement between experimental data and those predicted by proposed correlations withܴ ଶ greater than 0.99.https://www.ijche.com/article_10200_c1c6fff1643a3af5bd167488ff19012d.pdfIranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401Reduction of Parasitic Currents in Simulation of Droplet Secondary Breakup with Density Ratio Higher than 60 by InterDyMFoam294210201ENS.TavangarCFD Research Laboratory, School of Chemical Engineering, Iran University of Science
And Technology, Tehran, IranS.H.HashemabadiCFD Research Laboratory, School of Chemical Engineering, Iran University of Science
And Technology, Tehran, IranA.SaberimoghadamCFD Research Laboratory, School of Chemical Engineering, Iran University of Science
And Technology, Tehran, IranJournal Article20150727Secondary breakup of Newtonian droplet into continuous air jet was numerically studied. A coupled Large Eddy Simulation (LES)/ Volume of Fluid (VOF) technique was used in this investigation. Dynamic adaptive mesh was also employed. To this end, the open source CFD package, OpenFOAM, was used to perform the numerical study and was modified to meet the needs of the problem. In order to reduce the error, resulting from the spurious currents, Laplacian smoothing filter was used, which transforms the volume fraction into a smoother volume fraction. This filtering process also helped to obtain a sharp fluid interface. The smoothing has qualitatively and quantitatively improved the simulation results in bag breakup regime. Comparing the results of the RNG k-ε turbulence model and LES model showed the great influence of LES model to improve results. The detailed physics of two different breakup regimes, i.e. bag and multimode (streamer) were investigated. The numerical drop breakup regimes showed appropriate agreement with experimental observation. According to the analogy between the secondary and primary atomization, the outcomes can be used for development of the atomization models.https://www.ijche.com/article_10201_7fd3b80fb1884e2927df46a7139bb8bf.pdfIranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401Convective Heat Transfer Enhancement of CNT-Water Nanofluids in Plain Tube Fitted with Wire Coil Inserts435510202ENM.FallahiyektaDepartment of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IranM.R.Jafari NasrNanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran, IranA.RashidiNanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), Tehran, IranM.ArjmandDepartment of Chemical Engineering, South Tehran Branch, Islamic Azad University, Tehran, IranJournal Article20150727The turbulent convective heat transfer and pressure drop characteristics of CNT-water nanofluid in a horizontal tube fitted with wire coil inserts are studied experimentally. CNTs were synthesized by chemical vapor deposition (CVD) method with purity of more than 99%, functionalized by acid treatment and dispersed in distilled water in different concentrations. Also, the thermal conductivity and viscosity of synthesized nanofluids were measured experimentally. Convective heat transfer experiments are conducted with water and nanofluids in the range of 5000 < Re < 22000, CNT volume concentration 0 < ϕ < 0.1 % and wire coil with wire pitch of 2. The experimental results indicate that the convective heat transfer increases up to 23% in 0.05 vol% CNT-nanofluid and the heat transfer coefficient increases with CNT vol% and Reynolds number. Wire coil inserts increase the heat transfer coefficient of water and nanofluids up to 102% in Re=5700 but its performance decreases with Reynolds number. Experiments have shown that only use of wire coil inserts increases pressure drop of working fluid. Moreover, empirical correlations for Nusselt number and friction factor are proposed from nonlinear regression of the experimental data. Further, performance evaluation of enhanced tube is determined with considering opposing thermal resistance.https://www.ijche.com/article_10202_532a082cc38eaffa923d73bce41b4061.pdfIranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401Biosorption of cobalt (II) by Inta ct and Chemically Modified Brown Algae: Optimization Using Resp onse Surface Methodology and Equilibrium, Dynamics and Thermodynamics Studies567710203ENF.SoleymaniChemical Engineering Department, Tarbiat Modares University, Tehran, IranH.PahlevanzadehChemical Engineering Department, Tarbiat Modares University, Tehran, Iran0000-0001-5203-3566M.H.KhaniNuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, IranM.ManteghianChemical Engineering Department, Tarbiat Modares University, Tehran, IranJournal Article20150727By using response surface methodology, Batch shaking biosorption of cobalt (II) experiments were conducted in order to examine the combined effects of operating parameters. The results indicate that magnesium nitrate performed as an effective biosorbent surface modifier, which increases the rate of adsorption capacity. At optimal conditions (initial pH 7.0, temperature 45◦C, biosorbent concentration 0.1 g/100ml, and initial cobalt concentration 300mg/l for Mg-treated biomass) the biosorption capacity of the algae for cobalt was found to be 80.55 mg/g. The Langmuir and Freundlich isotherms were applied to the equilibrium data. The results are best fitted by the Freundlich model. Evaluation of the experimental data in terms of biosorption dynamics showed that the biosorption of cobalt (II) onto algal biomass followed the pseudo-second-order dynamics well. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the thermodynamic parameters (ΔG◦, ΔH◦ and ΔS◦) were also evaluated.https://www.ijche.com/article_10203_9af1b63534609a9c0068fef43dfb87e9.pdfIranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401Effect of Polymer Concentr ation on the Structure and Performance of Polysulf one Flat Membrane for CO 2 Absorption in Membrane Contactor789110204ENN.NabianChemical Engineering Department, Babol University of Technology, Babol, IranA.A.GhoreyshiChemical Engineering Department, Babol University of Technology, Babol, Iran0000-0002-2206-8802M.ShakeriMechanical Engineering Department, Babol University of Technology, Babol, IranJournal Article20150727In this study, polysulfone (PSF) flat membrane prepared via non-solvent phase inversion method was employed in gas-liquid membrane contactor module to absorb CO2. Two polymer concentrations of 16 wt% and 18 wt% were used in the dope solution of fabricated membranes. The membranes were characterized in terms of morphological structure and contact angle. Scanning electron microscopy (SEM) analysis demonstrated that PSF membrane with polymer concentration of 16 wt% in the dope solution has a porous layer with a combination of finger-like, sponge-like and macrovoid structures, but the other membrane has a sponge-like structure. Also, characterization results through atomic force microscopy (AFM) and contact angle measurement demonstrated that the porosity, surface roughness and hydrophobicity of the PSF membranes decreased with an increase in polymer concentration. Evaluationof mass transfer resistance displayed that the resistance of the PSF membrane with polymer concentration of 18wt% in the dope solution is higher than that of the other membrane. In addition, decreasing the polymer concentration significantly improved CO2 absorption flux. At the absorbent flow rate of 9.7 ml/min, the CO 2 absorption flux of PSF membrane with 16 wt% polymer concentration was 2.17 times higher than the absorption flux of the PSF with 18 wt% polymer concentration.https://www.ijche.com/article_10204_51ef70624ca791283ec434a52da0d4e2.pdfIranian Association of Chemical Engineering (IAChE)Iranian Journal of Chemical Engineering (IJChE)1735-539711220140401CFD Study of the Turbulent Forced Convective Heat Transfer of Non-Newtonian Nanofluid9210210205ENM.MoravejiChemical Engineering Department, Amirkabir University of Technology, Tehran, Iran0000-0003-4891-340XA.R.BeheshtiDepartment of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, IranJournal Article20150727In this study, forced convection heat transfer of non-Newtonian nanofluids in a horizontal tube with constant wall temperature under turbulent flow conditions was investigated using computational fluid dynamics tools. For this purpose, non-Newtonian nanofluids containing three types of nanoparticles (Al2O 3, TiO 2 and CuO) with carboxymethylcellulose aqueous solution as a liquid single phase with three average particle sizes of 10, 25 and 40 nm nanofluids were investigated. Effects of nanoparticle type and Peclet number on the convective heat transfer coefficient were investigated in fully turbulent region of a horizontal tube. A correlated equation was obtained for Nusselt number using the dimensionless numbers by applying the simulation results. Results showed that the correlated data were in very good agreement with the experimental ones obtained from the literature. The maximum error was 12%.https://www.ijche.com/article_10205_5d541464ac15bfb8f0a537b010d13fa1.pdf