Prof. Dr. Ing. Menwer Attarakih - Profile on Academia.edu (original) (raw)

Papers by Prof. Dr. Ing. Menwer Attarakih

E3S Web of Conferences, 2021

Adsorption cooling is a promising technology to recover low-temperature waste heat from a diesel ... more Adsorption cooling is a promising technology to recover low-temperature waste heat from a diesel genset. In this paper, an advanced adsorption chiller working in variable mode is proposed for the combined cooling and power cycle (CCP) to recover waste heat from the water jacket in the diesel genset. The chiller works on three modes based on the ambient temperature for better heat utilization. In this study, three modes were investigated: single-stage cycle mode, short-duration, and medium-duration mass recovery modes. The results show that the energy and exergy efficiency for a single-stage cycle mode is higher at an ambient temperature lower than 35 °C . In comparison, the mass recovery mode has a higher energy and exergy efficiency at an ambient temperature higher than 35 °C. The annual energy and exergy efficiency for the CCP was investigated when the chiller works with variable modes based on the ambient temperature under DUBAI weather conditions as a case study. The results sho...

Energies, 2021

Adsorption cooling can recover waste heat at low temperature levels, thereby saving energy and re... more Adsorption cooling can recover waste heat at low temperature levels, thereby saving energy and reducing greenhouse gas emissions. An air-cooled adsorption cooling system reduces water consumption and the technical problems associated with wet-cooling systems; however, it is difficult to maintain a constant recooling water temperature using such a system. To overcome this limitation, a variable mode adsorption chiller concept was introduced and investigated in this study. A prototype adsorption chiller was designed and tested experimentally and numerically using the lumped model. Experimental and numerical results showed good agreement and a similar trend. The adsorbent pairs investigated in this chiller consisted of silicoaluminophosphate (SAPO-34)/water. The experimental isotherm data were fitted to the Dubinin–Astakhov (D–A), Freundlich, Hill, and Sun and Chakraborty (S–C) models. The fitted data exhibited satisfactory agreement with the experimental data except with the Freundlic...

Energies, 2021

We conducted energy and exergy analyses of an adsorption chiller to investigate the effect of rec... more We conducted energy and exergy analyses of an adsorption chiller to investigate the effect of recooling-water temperatures on the cooling capacity and Coefficient of Performance (COP) with variable cycle modes. We investigated both the effect of the recooling-water temperature and the dead state temperature on the exergy destruction in the chiller components. Our results show that there is an optimum reheat cycle mode for each recooling-water temperature range. For the basic single stage cycle, the exergy destruction is mainly accrued in the desorber (49%), followed by the adsorber (27%), evaporator (13%), condenser (9%), and expansion valve (2%). The exergy destruction for the preheating process is approximately 35% of the total exergy destruction in the desorber. By contrast, the precooling process is almost 58% of the total exergy destruction in the adsorber. The exergy destruction decreases when increasing the recooling-water and the dead state temperatures, while the exergy eff...

This work reports the numerical performance of the Normalized Quadrature Method of Moments (NQMOM... more This work reports the numerical performance of the Normalized Quadrature Method of Moments (NQMOM) involving more than one quadrature node (secondary particle) for dispersed phase flows coupled with the Finite Pointset Method (FPM). At first, the model used for the dispersed phase acting in a continuous environment is discussed briefly, followed by a theoretical discussion of NQMOM and FPM. Further sections report the numerical performance for test problems with increasing difficulty.

Computer Aided Chemical Engineering, 2005

In this work, the advantages of the generalized fixed pivot technique as extended to mass transfe... more In this work, the advantages of the generalized fixed pivot technique as extended to mass transfer and the quadrature method of moments are utilized to reduce the bivariate spatially distributed population balance equation describing the coupled hydrodynamics and mass transfer in liquid-liquid extraction columns. The proposed reduction technique is found to reduce the discrete system of partial equations from 2M x +1 to M x +2, where M x is the number of pivots or classes. The spatial variable is discretized in a conservative form using a couple of recently published central difference schemes. The numerical predictions of the detailed and reduced models are found almost identical accompanied by a substantial reduction of the CPU time as a characteristic of the reduced model.

Lecture Notes in Computational Science and Engineering

In this paper we present the liquid-liquid two-phase flow simulations of a stirred extraction col... more In this paper we present the liquid-liquid two-phase flow simulations of a stirred extraction column with the help of our own developed meshfree method called the Finite Pointset Method (FPM). The primary (continuous) phase is modeled by the incompressible Navier-Stokes equations. The motion of the secondary (dispersed) phase is simulated by solving the equation of motion in which inertia, drag and buoyancy forces are taken into account. The size of the droplets is obtained by solving the droplet population balance equation (DPBE). The DPBE is solved by the Sectional Quadrature Method of Moments (SQMOM). The coupling between both phases is performed by considering the momentum transfer from each phase. In this work, some simulations in two and three dimensional cases with constant breakage and aggregation kernels are presented.

CFD-population balance modeling and simulation of coupled hydrodynamics and mass transfer in liquid extraction columns

Applied Mathematical Modelling, 2015

ABSTRACT Abstract A hierarchical approach for modelling and simulation of coupled hydrodynamics a... more ABSTRACT Abstract A hierarchical approach for modelling and simulation of coupled hydrodynamics and mass transfer in liquid extraction columns using detailed and reduced bivariate population balance models is presented. The hierarchical concept utilizes a one-dimensional CFD model with detailed bivariate population balances. This population balance model is implemented in the PPBLAB software, which is used to optimize the column hydrodynamics. The optimized droplet model parameters (droplet breakage and coalescence) are then used by a two-dimensional CFD reduced population balance model. As a reduced bivariate population balance model, OPOSPM (One Primary and One Secondary Particle Method) is implemented in the commercial FLUENT software to predict the coupled hydrodynamics and mass transfer of an RDC extraction column with 88 compartments. The simulation results show that the coupled two-dimensional-OPOSPM model produces results that are very close to that of the one-dimensional PPBLAB detailed population balance model. The advantages of PPBLAB are the ease of model setup, implementation and the reduced simulation time (order of minutes), when compared to the computational time (order of weeks) and computational resources using FLUENT software. The advantages of the two-dimensional CFD model is the direct estimation of the turbulent energy dissipation using the k-ε model and the local resolution of continuous phase back mixing.

A CFD-Population Balance Model for the Simulation of Kühni Extraction Column

Computer Aided Chemical Engineering, 2011

In this work, computational fluid dynamics (CFD) calculations coupled with DPBM are compared to L... more In this work, computational fluid dynamics (CFD) calculations coupled with DPBM are compared to LLECMOD (Liquid-Liquid Extraction Column MODule) simulations and to Laser Induced Fluorescence (LIF) measurement of the phase fraction using an iso-optical system of calcium chloride/water and butyl acetate. The results show a good agreement between the simulations and experimental data. The CFD requires a high computational load

Computer Aided Chemical Engineering, 2011

A comprehensive bivariate population balance model for the dynamic and steady state simulation of... more A comprehensive bivariate population balance model for the dynamic and steady state simulation of extraction columns is developed. The model is programmed using visual digital FORTRAN and then integrated into the whole LLECMOD program [23]. As a case study, the simulation tool LLECMOD is used to simulate the steady state performance of pulsed packed and sieve plate columns. Two chemical test systems recommended by the EFCE are used in the simulation. Model predictions are successfully validated against steady state and dynamic experimental data, where good agreements are achieved.

Procedia Engineering, 2012

This work presents a new windows-based MATLAB program, which is called PPBLAB (Particulate Popula... more This work presents a new windows-based MATLAB program, which is called PPBLAB (Particulate Population Balance Laboratory) for modelling and numerical simulation of particulate systems. As a first step, liquid-liquid extraction columns are modelled using the population balance equation as a mathematical framework. Up to date population balance models and solvers are incorporated. The discretization of the spatial domain is based on the finite volume method with flux vector splitting. A strongly stable semi-implicit first order time integration scheme is used to resolve such a large and stiff ODE system. The MATLAB GUI is used to make PPBLAB a user friendly program, which allows the user to define and simulate liquid extraction columns. A thermodynamics package TEA-COCO, which obtained from CAPE-OPEN, is linked to PPBLAB. Therefore, a special interface is designed for the purpose of data exchange between PPBLAB and CAPE-OPEN TEA tool. The solute distribution coefficient in ternary systems is predicted using the UNIQUAQ model with a special optimization tool to estimate the binary interaction parameters based on infinite conditions. A pilot plant Kühni extraction column is simulated and tested. Full analysis and performance of the PPBLAB are carried out and validated against experimental data.

Procedia Engineering, 2012

The present work highlights the powerful combination of SIMULINK/MATLAB software as an effective ... more The present work highlights the powerful combination of SIMULINK/MATLAB software as an effective flowsheeting tool which was used to simulate steady state and closed loop dyanmics of a sieve tray gas absorption column. A complete mathematical model, which consists of a system of differential and algebraic equations was developed. As a case study, the dynamic behaviour and control of a sieve tray column to absorb ethanol from CO 2 stream in a fermentation process were analyzed. The nonlinearity increased along the column height and was maximum at the top tray. The controlled variable was found to exhibit fairly large overshoots due to step change in the inlet gas flow rate, while the PID controller performance was satisfactory for step change in the inlet gas composition. The closed-loop dynamic analysis showed that the controlled variable (outlet gas phase composition) had a fairly linear dynamics due to step changes in the set point.

The hydrodynamic and mass transfer behavior of a Rotating Disk Contactor (RDC) extraction column ... more The hydrodynamic and mass transfer behavior of a Rotating Disk Contactor (RDC) extraction column is investigated for two different liquid-liquid systems recommended by the European Federation of Chemical Engineering (EFCE). An inverse problems method is applied to estimate the coalescence parameters in a RDC extraction column. Single-droplet studies in a small lab scale RDC is used to evaluate the coalescence parameters necessary for column simulations, which were obtained by an inverse solution of the population balance model using the generalized fixed-pivot technique for the discretization of the droplet internal coordinate. The coalescence parameters resulted from solving the inverse problem are dependent on the chemical test system used for the simulation. Then the resulted coalescence parameters values were used in LLECMOD to study the hydrodynamic and mass transfer behavior of pilot plant of RDC extraction column. The simulated Sauter mean droplet diameter, holdup values and concentration profiles for organic and aqueous phase were found to be well predicted compared to the experimental data.

Industrial & Engineering Chemistry Research, 2010

In this work, a one-group reduced population balance model based on the one primary and one secon... more In this work, a one-group reduced population balance model based on the one primary and one secondary particle method (OPOSPM) developed recently by Attarakih et al. (In

Chemie Ingenieur Technik, 2011

Moderne Methoden auf Basis von Tropfenpopulationsbilanzen erlauben eine schnelle und präzise Bere... more Moderne Methoden auf Basis von Tropfenpopulationsbilanzen erlauben eine schnelle und präzise Berechnung von wichtigen Größen in der Extraktionskolonne. Die Ansätze zeigen eine gute Übereinstimmung der Experimente mit Simulationen und Abweichungen im Sauter-Durchmesser d 32 von unter 5 % (Rührkessel 450 mm) und 7-12 % (Kolonne 450 mm). Mit Hilfe optischer Messtechnik werden Tropfenschwärme transient untersucht. Die Grenze der optischen Durchlichtmesstechnik liegt bei einer Konzentration von 16-20 %, im Auflicht ist eine Konzentration von > 30 % möglich. Die Analyse der Tropfenabbildungen erfolgt mit Hilfe der Bildalgorithmen Distanztransformation und Wasserscheiden-Segmentierung.

Chemical Engineering Science, 2004

In liquid-liquid contacting equipment such as completely mixed and di erential contactors, drople... more In liquid-liquid contacting equipment such as completely mixed and di erential contactors, droplet population balance based modeling is now being used to describe the complex hydrodynamic behavior of the dispersed phase. For the hydrodynamics of these interacting dispersions this model accounts for droplet breakage, droplet coalescence, axial dispersion, exit and entry events. The resulting population balance equations are integro-partial di erential equations (IPDE) that rarely have an analytical solution, especially when they show spatial dependency, and hence numerical solutions are sought in general. To do this, these IPDEs are projected onto a system of convective dominant partial di erential equations by discretizing the droplet diameter (internal coordinate). This is accomplished by generalizing the ÿxed-pivot (GFP) technique of Kumar and Ramkrishna (Chem. Eng. Sci. 51 (1996a) 1311) handling any two integral properties of the population number density for continuous ow systems by treating the inlet feed distribution as a source term. Moreover, the GFD technique has the advantage of being free of repeated or double integral evaluation resulting from the weighted residual approaches such as the Galerkin's method. This allows the time-dependent breakage and coalescence functions to be easily handled without appreciable increase in the computational time. The resulting system of PDEs is spatially discretized in conservative form using a simpliÿed ÿrst order upwind scheme as well as ÿrst-and second-order non-oscillatory central di erencing schemes. This spatial discretization avoids the characteristic decomposition of the convective ux based on the approximate Riemann solvers and the operator splitting technique required by classical upwind schemes. The time variable is discretized using an implicit strongly stable approach that is formulated by careful lagging of the non-linear parts of the convective and source terms. The algorithm is tested against analytical solutions of the simpliÿed population balance equation for a di erential liquid-liquid extraction column through four case studies. In all these case studies the discrete models converge successfully to the available analytical solutions and to solutions on relatively ÿne grids when the analytical solution is not available. Realization of the algorithm is accomplished by comparing its predictions to experimental steady-state hydrodynamic data of a laboratory scale rotating disc contactor of 0:15 m diameter. Practically, the combined algorithm is found fast enough for the computation of the transient and steady-state hydrodynamic behavior of the continuously and spatially distributed interacting liquidliquid dispersions.

Chemical Engineering Science, 2003

The numerical solution of droplet population balance equations (PBEs) by discretization is known ... more The numerical solution of droplet population balance equations (PBEs) by discretization is known to su er from inherent ÿnite domain errors (FDE). Tow approaches that minimize the total FDE during the solution of discrete droplet PBEs using an approximate optimal moving (for batch) and ÿxed (for continuous systems) grids are introduced. The optimal grids are found based on the minimization of the total FDE, where analytical expressions are derived for the latter. It is found that the optimal moving grid is very e ective for tracking out steeply moving population density with a reasonable number of size intervals. This moving grid exploits all the advantages of its ÿxed counterpart by preserving any two pre-chosen integral properties of the evolving population. The moving pivot technique of Kumar and Ramkrishna (Chem. Eng. Sci. 51 (1996b) 1333) is extended for unsteady-state continuous ow systems, where it is shown that the equations of the pivots are reduced to that of the batch system for su ciently ÿne discretization. It is also shown that for a su ciently ÿne grid, the di erential equations of the pivots could be decoupled from that of the discrete number density allowing a sequential solution in time. An optimal ÿxed grid is also developed for continuous systems based on minimizing the time-averaged total FDE. The two grids are tested using several cases, where analytical solutions are available, for batch and continuous droplet breakage in stirred vessels. Signiÿcant improvements are achieved in predicting the number densities, zero and ÿrst moments of the population.

Chemical Engineering Science, 2012

We modeled a high-pressure oil splitting reactor using reduced population balances. c Simultaneou... more We modeled a high-pressure oil splitting reactor using reduced population balances. c Simultaneous first-order chemical reaction and extraction are included. c Hyperbolicity of the model is analyzed to develop a finite volume method with flux vector splitting. c Reaction is found as controlling mechanism at low operating temperature (225 1C). c Mean droplet size affects both reactor hydrodynamics and mass transfer performance.

Coupling of CFD with DPBM for an RDC extractor

Chemical Engineering Science, 2009

For the design of counter-current liquid–liquid extraction columns, there is a strong industrial ... more For the design of counter-current liquid–liquid extraction columns, there is a strong industrial demand for more straightforward, faster and money-saving simulation methods. One possibility in this direction that has a great potential is the coupling of computational fluid dynamics (CFD) with population balance models (PBM). Therefore, a combination of CFD and droplet population balance modelling (DPBM) is applied to simulate

Modeling and dynamic analysis of a rotating disc contactor (RDC) extraction column using one primary and one secondary particle method (OPOSPM)

Chemical Engineering Science, 2013

ABSTRACT Modeling and dynamic analysis of liquid extraction columns are essential for the design,... more ABSTRACT Modeling and dynamic analysis of liquid extraction columns are essential for the design, control strategies and understanding of column behavior during start up and shutdown. Because of the discrete character of the dispersed phase, the population balance modeling framework is needed. Due to the mathematical complexity of the full population balance model, it is still not feasible for dynamic and online control purposes. In this work, a reduced mathematical model is developed by applying the concept of the primary and secondary particle method (Attarakih et al., 2009b, Solution of the population balance equation using the one primary and one secondary particle method (OPOSPM), Computer Aided Chemical Engineering, vol. 26, pp. 1333–1338). The method is extended to solve the nonhomogenous bivariate population balance equation, which describes the coupled hydrodynamics and mass transfer in an RDC extraction column. The model uses only one primary and one secondary particles, which can be considered as Lagrangian fluid particles carrying information about the distribution as it evolves in space and time. This information includes averaged quantities such as total number, volume and solute concentrations, which are tracked directly through a system of coupled hyperbolic conservation laws with nonlinear source terms. The model describes droplet breakage, coalescence and interphase solute transfer. Rigorous hyperbolic analysis of OPOSPM uncovered the existence of four waves traveling along the column height. Three of these are contact waves, which carry volume and solute concentration information. The dynamic analysis in this paper reveals that the dominant time constant is due to solute concentration in the continuous phase. On the other hand, the response of the dispersed phase mean properties is relatively faster than the solute concentration in the continuous phase. Special shock capturing method based on the upwind scheme with flux vector splitting is used, with explicit wave speeds, as a time–space solver. The model shows a good match between analytical and numerical results for special steady state and dynamic cases as well as the published steady state experimental data.

Chemical Engineering Science, 2006

A comprehensive model for predicting the interacting hydrodynamics and mass transfer is formulate... more A comprehensive model for predicting the interacting hydrodynamics and mass transfer is formulated on the basis of a spatially distributed population balance equation in terms of the bivariate number density function with respect to droplet diameter and solute concentration. The two macro-(droplet breakage and coalescence) and micro-(interphase mass transfer) droplet phenomena are allowed to interact through the dispersion interfacial tension. The resulting model equations are composed of a system of partial and algebraic equations that are dominated by convection, and hence it calls for a specialized discretization approach. The model equations are applied to a laboratory segment of an RDC column using an experimentally validated droplet transport and interaction functions. Aside from the model spatial discretization, two methods for the discretization of the droplet diameter are extended to include the droplet solute concentration. These methods are the generalized fixed-pivot technique (GFP) and the quadrature method of moments (QMOM). The numerical results obtained from the two extended methods are almost identical, and the CPU time of both methods is found acceptable so that the two methods are being extended to simulate a full-scale liquid-liquid extraction column.

E3S Web of Conferences, 2021

Energies, 2021

Computer Aided Chemical Engineering, 2005

Lecture Notes in Computational Science and Engineering

CFD-population balance modeling and simulation of coupled hydrodynamics and mass transfer in liquid extraction columns

Applied Mathematical Modelling, 2015

A CFD-Population Balance Model for the Simulation of Kühni Extraction Column

Computer Aided Chemical Engineering, 2011

Procedia Engineering, 2012

Industrial & Engineering Chemistry Research, 2010

Chemie Ingenieur Technik, 2011

Chemical Engineering Science, 2004

Chemical Engineering Science, 2003

Chemical Engineering Science, 2012

Coupling of CFD with DPBM for an RDC extractor

Chemical Engineering Science, 2009

Modeling and dynamic analysis of a rotating disc contactor (RDC) extraction column using one primary and one secondary particle method (OPOSPM)

Chemical Engineering Science, 2013

Chemical Engineering Science, 2006

1. To understand the importance of numerical methods in engineering. 2. To understand different n... more 1. To understand the importance of numerical methods in engineering. 2. To understand different numerical algorithms (such as computer arithmetic, solving algebraic and differential equations etc.) and implement them on a computer. 3. How to deal with programmed numerical techniques using high-level languages such as MATLAB.

Lab4

First Term 2014/2015 Mid Exam, Short & Full Reports Mean: 33.00 STD: 6.00 Number of Students... more First Term 2014/2015
Mid Exam, Short & Full Reports
Mean: 33.00
STD: 6.00
Number of Students: 23

Plant Design

First Term 2014/2015 Mid Exams, Project & Presentation Mean: 27.16 STD: 6.10 Number of Stud... more First Term 2014/2015
Mid Exams, Project & Presentation
Mean: 27.16
STD: 6.10
Number of Students: 25

Process design

First Term 2014/2015 Mid Exams, Project & Presentation Mean: 25.58 STD: 7.70 Number of Stude... more First Term 2014/2015
Mid Exams, Project & Presentation
Mean: 25.58
STD: 7.70
Number of Students: 50