The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Zhaoping Zhong - One of the best experts on this subject based on the ideXlab platform.
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study of the separation efficiency of a Demister vane with response surface methodology
Journal of Hazardous Materials, 2007Co-Authors: Jianzhi Zhao, Zhaoping ZhongAbstract:Numerical simulations of a Demister vane with various geometries and operating conditions were performed to study the separation efficiency. The numerical solutions were carried out using commercial CFD code Fluent 6.1. A prediction model of the separation efficiency was obtained based on response surface methodology by means of the statistical software program Minitab V14. The results show that not only the vane spacing and flue gas velocity, but also vane height (including height of curve and upright region) and vane turning angles, play an important role in influencing the separation efficiency. Compared with some experimental and simulative conclusions, the results indicate that present prediction model can estimate the effects of different geometries and operation conditions on the separation efficiency, and can direct the optimum design of Demisters.
Hisham Ettouney - One of the best experts on this subject based on the ideXlab platform.
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eulerian lagrangian modeling and computational fluid dynamics simulation of wire mesh Demisters in msf plants
Desalination, 2016Co-Authors: Hala Alfulaij, Hisham Ettouney, Andrea Cipollina, Giorgio Micale, David BogleAbstract:Abstract This study focuses on computational fluid dynamics model (CFD) for simulation of Demisters in multistage flash desalination (MSF). The Eulerian–Lagrangian model (steady-state and two-dimensional) was developed to simulate the Demister. The model was used to simulate the flow of water vapor and brine droplets in the Demister. The computational domain includes the following three zones: the vapor space above the Demister, the vapor space below the Demister, and the Demister. The Demister zone was modeled as tube banks. A sensitivity analysis of the model revealed that vapor velocity is the main parameter that affects Demister performance. Additionally, the analysis indicated that vapor temperature had no effect on the pressure drop across the Demister. The developed model was validated using data from both the literature and real MSF plants. Analysis indicated that model predictions and experimental data were consistent. This work gives extensive details for CFD modeling of the MSF Demister. The work is based on a previous study by Al-Fulaij et al. (2014). This work is part of a group effort to develop a comprehensive CFD simulation for the entire flashing stage of the MSF process, which would provide an extremely efficient and inexpensive design and simulation tool to the desalination community.
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Eulerian–Lagrangian modeling and computational fluid dynamics simulation of wire mesh Demisters in MSF plants
Desalination, 2016Co-Authors: Hala Al-fulaij, Hisham Ettouney, Andrea Cipollina, Giorgio Micale, David BogleAbstract:Abstract This study focuses on computational fluid dynamics model (CFD) for simulation of Demisters in multistage flash desalination (MSF). The Eulerian–Lagrangian model (steady-state and two-dimensional) was developed to simulate the Demister. The model was used to simulate the flow of water vapor and brine droplets in the Demister. The computational domain includes the following three zones: the vapor space above the Demister, the vapor space below the Demister, and the Demister. The Demister zone was modeled as tube banks. A sensitivity analysis of the model revealed that vapor velocity is the main parameter that affects Demister performance. Additionally, the analysis indicated that vapor temperature had no effect on the pressure drop across the Demister. The developed model was validated using data from both the literature and real MSF plants. Analysis indicated that model predictions and experimental data were consistent. This work gives extensive details for CFD modeling of the MSF Demister. The work is based on a previous study by Al-Fulaij et al. (2014). This work is part of a group effort to develop a comprehensive CFD simulation for the entire flashing stage of the MSF process, which would provide an extremely efficient and inexpensive design and simulation tool to the desalination community.
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Pressure drop across wire mesh Demister in desalination plants using Eulerian–Eulerian modeling and computational fluid dynamics simulation
Desalination and Water Treatment, 2015Co-Authors: Danah Al-rabiah, Hala Al-fulaij, Hisham EttouneyAbstract:AbstractThis study focuses on the development of design correlation for pressure drop in wire mesh Demisters, used in the multistage flash desalination process (MSF) as well as similar evaporation and flashing units found in other industrial processes. Development of the correlation is based on numerical simulation of the Demister using steady-state and two-dimensional model for the flow of vapor and brine droplets through the Demister. An Eulerian model was used to model the system and the resulting model equations were solved using a commercial computational fluid dynamics software (FLUENT). The system model was formed of three zones, which include the vapor space above and below the Demister and the Demister. In addition, the Demister was approximated as a porous media. A sensitivity analysis of the model revealed that vapor velocity, Demister packing density and height, and the inlet flashed-off vapor composition are the main parameters that affect Demister performance. Consequently, numerical data we...
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Eulerian-Eulerian modelling and computational fluid dynamics simulation of wire mesh Demisters in MSF plants
Engineering Computations, 2014Co-Authors: Hala Al-fulaij, Hisham Ettouney, Andrea Cipollina, Giorgio Micale, David BogleAbstract:Purpose – The purpose of this study is to focus on simulation of wire mesh Demisters in multistage flash desalination (MSF) plants. The simulation is made by the use of computational fluid dynamics (CFD) software. Design/methodology/approach – A steady state and two-dimensional (2D) model was developed to simulate the Demister. The model employs an Eulerian-Eulerian approach to simulate the flow of water vapor and brine droplets in the Demister. The computational domain included three zones, which are the vapor space above and below the Demister and the Demister. The Demister zone was modeled as a tube bank arrange or as a porous media. Findings – Sensitivity analysis of the model showed the main parameters that affect Demister performance are the vapor velocity and the Demister permeability. On the other hand, the analysis showed that the vapor temperature has no effect on the pressure drop across the Demister. Research limitations/implications – The developed model was validated against previous literat...
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CFD Modelling of the Demister in the Multi Stage Flash Desalination plant
Computer-aided chemical engineering, 2011Co-Authors: Hala Al-fulaij, Andrea Cipollina, Giorgio Micale, David Bogle, Hisham EttouneyAbstract:Abstract Demisters are used to remove entrained brine droplets from flashed off vapor within the flashing stages of the multi stage flash desalination process (MSF). This is necessary to prevent accumulation of brine droplets on the outside surface of the condenser tubes and contamination of the desalinated water. The aim of this work is to design a new Demister with lower pressure drop and unaffected separation efficiency which can be later installed in the flashing stages of the MSF plant and causes reduction in the required heat transfer area. In this work the Demister performance is predicted as a function of design (wire diameter), and operating parameters (stage temperature). This objective was pursued through the use of commercial computational fluid dynamics (CFD) software. The wire mesh Demister was modeled as a tube bank. The model was time dependent and was validated against experimental and field data obtained from large scale MSF units. This manuscript includes model development and computer solution using the FLUENT code. The model predictions for both experimental and large scale units show good agreement of measured pressure drop and separation efficiency against data from existing MSF plants.
Jianzhi Zhao - One of the best experts on this subject based on the ideXlab platform.
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study of the separation efficiency of a Demister vane with response surface methodology
Journal of Hazardous Materials, 2007Co-Authors: Jianzhi Zhao, Zhaoping ZhongAbstract:Numerical simulations of a Demister vane with various geometries and operating conditions were performed to study the separation efficiency. The numerical solutions were carried out using commercial CFD code Fluent 6.1. A prediction model of the separation efficiency was obtained based on response surface methodology by means of the statistical software program Minitab V14. The results show that not only the vane spacing and flue gas velocity, but also vane height (including height of curve and upright region) and vane turning angles, play an important role in influencing the separation efficiency. Compared with some experimental and simulative conclusions, the results indicate that present prediction model can estimate the effects of different geometries and operation conditions on the separation efficiency, and can direct the optimum design of Demisters.
Hassan E.s. Fath - One of the best experts on this subject based on the ideXlab platform.
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CFD analysis of vapor flow and design improvement in MED evaporation chamber
Desalination and Water Treatment, 2014Co-Authors: M. Khamis Mansour, M.a. Qassem, Hassan E.s. FathAbstract:AbstractThis paper presents the Computational Fluid Dynamics (CFD) analysis of the vapor flow inside the Evaporation Chamber (EC) of a two-effect Multi-Effect Distillation (MED) unit. The study is part of the EU–Egypt funded project Multipurpose Applications by Thermodynamics Solar. The numerical analysis investigates the effect of velocity variations on the EC’s carryover factor and Demister pressure drop for different separation baffle configurations. The trajectory of liquid droplets was calculated using Lagrange approach. The computational model was verified by comparing the predicated results (vapor pressure drop through the Demister and separation efficiency) with those obtained from published data, with good agreement. At the design inlet vapor velocity of 3.3 m/s, a new baffle configuration is presented and is characterized by the best performance among the other configurations. This new baffle configuration shows a minimum carryover factor of 0.097 with a reasonable Demister pressure drop less th...
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Comparative study for different Demister locations in multistage flash (MSF) flash chamber (FC)
Desalination and Water Treatment, 2013Co-Authors: M. Khamis Mansour, Hassan E.s. FathAbstract:ABSTRACTMultistage flash (MSF) is a widely used technology in large capacity salted water desalination plants. The enhancement in the thermal performance of this technology is still prospective and promising. In this research, vapor flow through the flash chamber (FC) was studied. Flow development in 2D simulation model of a real FC was investigated. Trajectory of liquid droplets was calculated using Lagrange approach. The continuity and Navier–Stokes equations for the continuous phase “vapor” were solved simultaneously with the particle equation using two equations k–ϵ turbulence model. The computational model was verified by comparing the predicated results (vapor pressure drop through the FC Demister and moist separation efficiency) with those obtained from the published experimental data. The comparison showed a good agreement between both results with maximum deviation of less than −19.16%, however, most of the disagreement between both results is fewer than 10%. Four different Demister locations wer...
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numerical simulation of vapor flow and pressure drop across the Demister of msf desalination plant
Energy Conversion and Management, 2013Co-Authors: Isam Janajreh, Ashraf Hasania, Hassan E.s. FathAbstract:This paper presents a numerical simulation of the water vapor flow in an MSF flash chamber along with the pressure drop across the Demister. The Demister is a simple porous blanket of metal wires mesh (usually made of stainless steel wires) which retains liquid droplets entrained by the vapor momentum to enhance the quality of the product water. Two main areas of concern in wire mesh mist eliminators are; (i) the pressure drop and (ii) the mist removal efficiency. The present simulation focuses only on the pressure drop across the Demister. The simulation is carried out considering a full scale flashing chamber of a typical operational MSF desalination plant and of a real industrial Demister dimensions. The study simulates the Demister as porous media flow. It takes into account the vapor velocity, the dimension of the Demister, its porosity and wire thickness. The obtained pressure drop was found to be within a reasonable agreement with the published literature data and it follows a trend compatible with Ergun’s equation as well as the empirical correlation of Svendsen. 2012 Published by Elsevier Ltd.
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An online cleaning system to reduce Demister fouling in MSF Sidi Krir Desalination Plant, 2 × 5000 m3/day
Desalination, 2008Co-Authors: Hassan E.s. Fath, Mohamed A. IsmailAbstract:Abstract This paper discusses the Demister scaling issue in (MSF) 2 × 5000 m3/day Sidi Krir Desalination Unit’s site, and how like this issue affects directly in the performance of this system and in production rate too, which decreases gradually till 50%, in addition the unscheduled outage costs for acid cleaning or replacement of these Demister sheets by new ones. The fixing of an online cleaning system during operation was proposed using the flow of condensate brine heater discharge pumps through two headers are fixed at the both lateral side of those stages in which the scaled Demisters were recorded. The proposed system will maintain the performance and saves the costs of chemical cleaning and the unscheduled outage of the system. The technical and economical advantages of this proposal are highlighted.
Roohollah Rafee - One of the best experts on this subject based on the ideXlab platform.
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effects of wavelength and number of bends on the performance of zigzag Demisters with drainage channels
Applied Mathematical Modelling, 2016Co-Authors: M Hamedi H Estakhrsar, Roohollah RafeeAbstract:Abstract In this paper, the effects of number of bends and bend wavelength on droplet removal efficiency and pressure drop of a zigzag Demister with drainage channels have been numerically investigated. A combination of Eulerian-Lagrangian method with eddy interaction model (EIM) has been used for the simulation of the droplet dispersion in turbulent gas flow. The droplet collection efficiency has been calculated and compared with available experimental data to show the validity of the simulation. The Reynolds stress transport model (RSTM) was applied to model the turbulent airflow. The results show that applying more bends in the Demister reduces the filtration size of the Demister but it can increase the pressure drop significantly. On the other hand, the Demisters with small dimensionless bend wavelength have more pressure losses and higher droplet removal efficiencies.
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effects of wavelength and number of bends on the performance of zigzag Demisters with drainage channels
Applied Mathematical Modelling, 2016Co-Authors: M Hamedi H Estakhrsar, Roohollah RafeeAbstract:Abstract In this paper, the effects of number of bends and bend wavelength on droplet removal efficiency and pressure drop of a zigzag Demister with drainage channels have been numerically investigated. A combination of Eulerian-Lagrangian method with eddy interaction model (EIM) has been used for the simulation of the droplet dispersion in turbulent gas flow. The droplet collection efficiency has been calculated and compared with available experimental data to show the validity of the simulation. The Reynolds stress transport model (RSTM) was applied to model the turbulent airflow. The results show that applying more bends in the Demister reduces the filtration size of the Demister but it can increase the pressure drop significantly. On the other hand, the Demisters with small dimensionless bend wavelength have more pressure losses and higher droplet removal efficiencies.