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mass-transfer
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Simulation of Mass Transfer from Droplet in a Two Phase Liquid-liquid Extraction System
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Firoozabadi, Bahar (Co-Advisor)
Abstract
Mass transfer of a drop moving in a bulk fluid is an interesting subject which has attracted a lot of attention. Understanding effective parameters in this process would be helpful in order to increase the efficiency of the industrial processes related to mass transfer. In this research, the deformation and mas transfer of a moving drop was studied numerically. Navier-Stokes equations and concentration equation were solved separately with a VOF method in an axisymmetric domain using Fluent software. Comparision between numerical results and former experimental results proves the accuracy of the modelling in both fields of deformation and mass transfer. Moreover, effects of the physical...
Drying in Spouted Beds with Draft Tube
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Simulation runs have been conducted to predict the evolution of sand drying in conical spouted beds with a non-porous draft tube. In the simulation runs, the moisture content of the solid phase was assumed to be 7 % (kg water/kg sand). The simulation results were validated against experimental results reported by Olazar et al. and good agreement was obtained.Influences of various physical and geometrical parameters such as superficial gas velocity, inlet temperature, length and diameter of draft tube and initial moisture content on the sand drying were investigated. Temperature and gas velocity are the most important parameters for improving the drying process and reduce the drying time of...
Multi-Scale Lattice Boltzmann Simulation of Carbonate Rock Dissolution in Acidizing Process
, Ph.D. Dissertation Sharif University of Technology ; Ayatollahi, Shahabodin (Supervisor) ; Jamshidi, Saeed (Supervisor) ; Raoof, Amir (Co-Supervisor)
Abstract
During the Acidizing process in oil and gas reservoirs, the injected acid reacts with the rock grains, changes the rock pore structure and affects the flow conditions. Due to the presence of a large concentration gradient at the vicinity of the rock grains and the continuous changes in rock-fluid interfaces of the porous medium, the continuum assumption has been remained debatable for the effective local mass transport and effective molecular diffusion coefficients and the porosity-permeability relation in the continuum scale modeling of this process. Therefore, the need for pore scale modelling is evident. The novelty of this study relies in adapting the grid refinement method on the...
Heat and Mass Transfer in a Finite Channel
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
The need for cooling and creating thermal comfort conditions for human life is one of today's severe challenges. Therefore, development and innovation to enhance the efficiency of these systems are of great importance. Among the new ideas proposed in this domain, we can mention the M-cycle, which can greatly improve the energy consumption for cooling systems in this sector. In this cycle, the desired cooling is produced by utilizing the latent heat of water evaporation, which is considered a kind of renewable energy. The systems based on this cycle are still under development, and for this reason, there is a necessity to better investigate the heat and mass transfer in the aforementioned...
Geometrically nonlinear rectangular simply supported plates subjected to a moving mass
, Article Acta Mechanica ; Vol. 225, issue. 2 , February , 2014 , pp. 595-608 ; ISSN: 00015970 ; Rofooei, F. R ; Sharif University of Technology
Abstract
The dynamic deformation of a geometrically nonlinear rectangular simply supported plate under a moving lumped mass is evaluated using mode expansion method. The governing differential equations of motion for a largely deformable rectangular plate are derived using Lagrange method based on appropriate in and out-of-plane spatial functions which satisfy the proposed boundary conditions. Although the proposed procedure is applicable for any arbitrary edge boundary conditions, only the simply supported plates are addressed in the present work. On the other hand, all inertial components of the moving mass are included in the derivation of the equations of motion. A numerical example is used to...
Experimental investigation of effects of mach number on the flow instability in a supersonic inlet
, Article Experimental Techniques ; Volume 37, Issue 3 , 2013 , Pages 46-54 ; 07328818 (ISSN) ; Farahani, M ; Sharif University of Technology
2013
Abstract
An extensive wind tunnel tests were conducted on an axisymmetric supersonic inlet at Mach numbers from 1.8 to 2.2 and at different values of mass flow rates. Frequencies of the buzz were achieved from the pressure data as well as the high speed shadowgraph pictures. For each Mach number, two main frequencies for the buzz were obtained. The inlet at its design condition was stable, but when the mass flow rate was reduced, at first the shock wave started to oscillate with a small amplitude which is matched the Ferri criterion (little buzz). In this situation, both high- and low-frequency oscillations occurred; however, the high frequency one was dominant, but the oscillations seemed to be...
Detail study on improving micro/nano gas mixer performances in slip and transitional flow regimes
, Article Sensors and Actuators, B: Chemical ; Volume 218 , October , 2015 , Pages 78-88 ; 09254005 (ISSN) ; Sabouri, M ; Sharif University of Technology
Elsevier
2015
Abstract
The mixer geometry has substantial effect on mixing performance of different micro/nanomixers. Despite past numerous studies dedicated to mixing of liquid flow streams, there are less efforts to investigate the geometry effects on gas mixing performances. In this work, we focus on gas-gas mixing through different micro/nanoscale mixers under slip and transitional flow regimes. We use the direct simulation Monte Carlo (DSMC) method to provide accurate and reliable results in such flow regimes. To extend our study, we implement different geometrical parameters in our consideration including the mixer size, the impact angle between two incoming gas streams, and the contraction height located in...
An applicable method for efficiency estimation of operating tray distillation columns and its comparison with the methods utilized in HYSYS and Aspen Plus
, Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 51, Issue 10 , October , 2015 , Pages 1393-1402 ; 09477411 (ISSN) ; Sharif University of Technology
Springer Verlag
2015
Abstract
Developing general methods that rely on column data for the efficiency estimation of operating (existing) distillation columns has been overlooked in the literature. Most of the available methods are based on empirical mass transfer and hydraulic relations correlated to laboratory data. Therefore, these methods may not be sufficiently accurate when applied to industrial columns. In this paper, an applicable and accurate method was developed for the efficiency estimation of distillation columns filled with trays. This method can calculate efficiency as well as mass and heat transfer coefficients without using any empirical mass transfer or hydraulic correlations and without the need to...
Optimal design of the volute for a turbocharger radial flow compressor
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 229, Issue 6 , July , 2015 , Pages 993-1002 ; 09544100 (ISSN) ; Hajilouy Benisi, A ; Movahhedy, M. R ; Sharif University of Technology
SAGE Publications Ltd
2015
Abstract
In this research, design methods of radial flow compressor volutes are reviewed; the main criteria in volute primary designs are recognized and the most effective ones are selected. The effective parameters, i.e., spiral cross-section area, circumferential area distribution, exit cone, and tongue area of the compressor volute are parametrically studied to identify the optimum values. A numerical model has been prepared and verified through experimental data which are obtained from the designed turbocharger test rig. Different volutes are modeled and numerically evaluated using the same impeller and vane-less diffuser. For each model, the volute total pressure ratio, static pressure recovery...
Effects of boundary-layer bleed parameters on supersonic intake performance
, Article Journal of Propulsion and Power ; Volume 31, Issue 3 , March , 2015 , Pages 826-836 ; 07484658 (ISSN) ; Younsi, J. S ; Farahani, M ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2015
Abstract
The performance and the buzz onset of a supersonic mixed-compression axisymmetric intake are experimentally investigated. Effectsof the slot bleed position, angle, and width onthe intake performance and onthe buzz initiation at three different Mach numbers of 1.8, 2.0, and 2.2 and at a zero degree angle of attack are studied. The intake performance is assessed using the total pressure recovery, mass flow ratio, flow distortion, and bleed mass flow ratio. The results show that applying the bleed at a position near the intake entrance and reducing the bleed entrance slant angle and width all improve the intake performance considerably. Moreover, these parameters postpone the buzz onset. In...
Computational investigation of graphene behavior under differential water pressure and possible mass transfer influences
, Article ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2016, 4 January 2016 through 6 January 2016 ; Volume 2 , 2016 ; 9780791849668 (ISBN) ; Darbandi, M ; Saidi, M.S ; Heat Transfer Division ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
Because of its unique properties, graphene has attracted the attentions of many academic research groups and recently, the industry. One of the promising applications of the graphene is in micro/nano-sensors, e.g. using it as a pressure sensor. To use it in mechanical-based nano-sensors, it is very important to investigate the mechanical behavior of the nano-sized graphene sheet and its sensitivity to the medium changes applied on its faces. In this work, we use the molecular dynamics MD method and simulate the behavior of graphene sheet under differential water pressure influences. In this regard, a square straight monolayer graphene sheet is placed as a separator diaphragm between two...
Numerical investigation of solidification of single droplets with and without evaporation mechanism
, Article International Journal of Refrigeration ; Volume 73 , 2017 , Pages 219-225 ; 01407007 (ISSN) ; Farhadi, F ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
According to some experimental observations, water droplet with high initial temperature freezes faster than a cold one. There are some explanations to this problem such as sub-cooling, evaporation and radiation. In this work, solidification process of single droplets with and without the effect of evaporation is numerically investigated for three different drop diameters and initial temperatures. It seems that evaporation itself is able to explain why hot water freezes faster than cold water. © 2016 Elsevier Ltd and IIR
Invariance in growth and mass transport
, Article Mathematics and Mechanics of Solids ; Volume 24, Issue 6 , 2019 , Pages 1707-1713 ; 10812865 (ISSN) ; Epstein, M ; Sharif University of Technology
SAGE Publications Inc
2019
Abstract
The equations of balance of a continuum under conditions of growth and mass diffusion are derived from a principle of invariance under general observer transformations. The resulting equations are invariant under inertial transformations. Apparent body forces stemming from the mass transport phenomenon are identified and shown to be associated with non-inertial observers
Three-dimensional compressible-incompressible turbulent flow simulation using a pressure-based algorithm
, Article Computers and Fluids ; Volume 37, Issue 6 , 2008 , Pages 747-766 ; 00457930 (ISSN) ; Darbandi, M ; Taeibi Rahni, M ; Sharif University of Technology
2008
Abstract
In this work, we extend a finite-volume pressure-based incompressible algorithm to solve three-dimensional compressible and incompressible turbulent flow regimes. To achieve a hybrid algorithm capable of solving either compressible or incompressible flows, the mass flux components instead of the primitive velocity components are chosen as the primary dependent variables in a SIMPLE-based algorithm. This choice warrants to reduce the nonlinearities arose in treating the system of conservative equations. The use of a new Favre-averaging like technique plays a key role to render this benefit. The developed formulations indicate that there is less demand to interpolate the fluxes at the cell...
Desulfurization of liquid-phase Butane by zeolite molecular sieve 13X in a fixed bed: Modeling, simulation, and comparison with commercial-scale plant data
, Article Energy and Fuels ; Volume 22, Issue 1 , 2008 , Pages 570-575 ; 08870624 (ISSN) ; Molaei Dehkordi, A ; Goodarznia, I ; Sharif University of Technology
2008
Abstract
This paper deals with the modeling and simulation of binary liquid-phase adsorption of methyl mercaptan and hydrogen sulfide from a liquid butane stream by zeolite molecular sieve 13X in a fixed bed. The model equations account for the effect of axial dispersion and the inter- and intraparticle, mass-transfer resistances at isothermal operating conditions. Orthogonal collocation and Gill's fourth-order Runge-Kutta methods were used to solve the dimensionless general forms of the 4N-eoupled ordinary differential equations for simultaneous adsorption of the solutes by the adsorbent in a fixed bed. The model predictions were compared to the commercial-scale plant data of an Iranian...
Experimental and computational investigation into the use of co-flow fluidic thrust vectoring on a small gas turbine
, Article Aeronautical Journal ; Volume 112, Issue 1127 , 2008 , Pages 17-25 ; 00019240 (ISSN) ; Saghafi, F ; Ghoreyshi, M ; Pilidis, P ; Sharif University of Technology
Royal Aeronautical Society
2008
Abstract
This paper presents the application of a relatively new technique of fluidic thrust-vectoring (FTV), named Co-flow, for a small gas-turbines. The performance is obtained via experiment and computational fluid dynamics (CFD). The effects of a few selected parameters including the engine throttle setting, the secondary air mass-flow rate and the secondary slot height upon thrust-vectoring performance are provided. Thrust vectoring performance is characterised by the ability of the system to deflect the engine thrust with respect to the delivered secondary air mass-flow rate. The experimental study was conducted under static conditions in an outdoor environment at Cranfield University workshop...
Experimental investigation of the effects of surfactants on the mass transfer in liquid-liquid extraction equipment
, Article 2007 5th Joint ASME/JSME Fluids Engineering Summer Conference, FEDSM 2007, San Diego, CA, 30 July 2007 through 2 August 2007 ; Volume 2 FORA, Issue PART A , 2007 , Pages 239-244 ; 0791842886 (ISBN); 9780791842881 (ISBN) ; Shah Alami, M ; Mansouri, H ; Sharif University of Technology
2007
Abstract
Mass transfer rates to the drops in liquid-liquid extraction equipment are often likely to be reduced by the presence of surface active contaminants. This reduction in mass transfer is said to be due to a reduction in terminal velocity, and to changes in pattern of internal circulation. A single-drop extraction apparatus was used to investigate the dependency of mass transfer coefficient on the amount of surfactant added in a system of n-butanol/succinic acid/water. Three types of surfactants, SDS, DTMAC and Triton X-100, were used to study their effects on the inhibition of mass transfer in liquid-liquid extraction. The effect of surfactants concentration on extraction percentage, overall...
Modeling of multiple noncatalytic gas-solid reactions in a moving bed of porous pellets based on finite volume method
, Article Heat and Mass Transfer/Waerme- und Stoffuebertragung ; Volume 43, Issue 9 , 2007 , Pages 881-894 ; 09477411 (ISSN) ; Saboohi, Y ; Sharif University of Technology
2007
Abstract
A mathematical model is presented to simulate the multiple heterogeneous reactions with complex set of physicochemical and thermal phenomena in a moving bed of porous pellets. This model is based on both heat and mass transfer phenomena of gaseous species in a porous medium including chemical reactions at interfaces whose areas vary during the conversion. This model accounts for both the exothermic and endothermic reactions which can be equimolar or nonequimolar. Furthermore it considers simultaneously the reactions in the nonisothermal transient condition. A powerful technique based upon finite volume fully implicit approach has been implemented to solve the complicated governing equations...
A three dimensional CFD modeling of hydrodynamics and mass transfer in a gas-liquid impeller stirred tank reactor
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Bozorgmehry Boozarjomehry, R ; Kazemeini, M ; Sharif University of Technology
2006
Abstract
Multiphase impeller stirred tank reactors enhance mixing of reacting species used in a variety of chemical industries. Gas-liquid mixing and mass transfer between these phases is an important application in reactor design. One such an example is hydrogenation reaction of aqueous NDMA (Nitroso dimethyl amine) solution in which one of the parameters having a significant effect on the reaction rate is mass transfer. This parameter in turn is a function of impeller shape and rotational speed, gas flow rate and reactor scale. Computational Fluid Dynamics (CFD) is a useful tool in the analysis, design and scale up of stirred tank reactors via investigating hydrodynamics of gas and liquid flow,...
Investigation of a two impinging-jets contacting device for liquid-liquid extraction processes
, Article Chemical Engineering Science ; Volume 61, Issue 12 , 2006 , Pages 3942-3950 ; 00092509 (ISSN) ; Ebrahimzadeh Zonouzian, S. A. R ; Molaei Dehkordi, A ; Sharif University of Technology
Elsevier Ltd
2006
Abstract
A two impinging-jets contacting device (TIJCD) for liquid-liquid extraction processes was proposed and tested through the standard test system recommended by the European Federation of Chemical Engineering (EFCE), toluene-acetone-water, as a typical example of liquid-liquid extraction processes. The results obtained for the overall volumetric mass transfer coefficient (capacity coefficient) were more than three times higher than those reported in the conventional contactors and in an air-driven two impinging-streams contactor. These experimental results clearly indicate the greater performance capability of TIJCD relative to those of conventional contactors. To have a perfect study on the...