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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.

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.

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.

The developed model was validated against previous literature data as well as real plant data. The analysis shows good agreement between model prediction and data.

This work is the first in the literature to simulate the MSF demister using CFD modeling. 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.

This paper aims to shows the ability of the EDC model with a global reaction mechanism to describe reactions in the Eulerian simulation of a circulating fluidized bed (CFB).

The eddy dissipation concept (EDC) model is embedded in an Eulerian-Eulerian approach to simulate homogeneous reactions.

EDC_G is better than ED_FR in describing chemical reactions. The reaction of CH₄ with O₂ is faster than that of CO with O₂, and NH₃ is more liable to be converted than HCN. The combustion rate is higher than the Boudouard reaction rate of coal particles.N₂O is mainly reduced by carbon, and NO is mainly converted by carbon into N₂ and CO₂.

The EDC model with a global reaction mechanism is embedded in a multi-fluid Eulerian approach to simulate the homogeneous reactions in the coal combustion in a CFB, including combustion of volatile gases, desulfurizing reactions and NO_x reactions.

The purpose of the present investigation is to compute the circulation flow of a liquid in a closed chamber when the liquid is fired by a gas jet through number of nozzles.

The conservation equations for mass and momentum have been solved in a closed container along with the conservation of volume fraction of the secondary phase in order to take into account the gas phase present in the liquid. The drag force created by the gas on the liquid has been incorporated in the momentum equation as a source term and the resulting equations have been solved numerically using a finite volume technique in an unstructured grid employing a phase coupled pressure linked velocity solver for the pressure correction equation, which is usually known as the Eulerian Scheme for two phase flow solution. An eddy viscosity based k‐ε turbulence model for the mixture was considered to update the fluid viscosity with iterations and capture the turbulence in the overall mixture rather than computing the individual turbulence in both the phases, which was found to be extremely time‐consuming and computationally unstable to some extent.

The model thus developed was tried to predict the circulation flow rate in an experimental setup where air was injected to drive the water in a long U tube setup. The computed circulation flow rate was found to be within 15 percent deviation from the experimentally observed values. The circulation flow rate of water was found to be increasing with the injected airflow rate. After this model validation, circulation flow rate of steel in an industrial size Ruhrstal‐Haraeus (RH)‐degasser was computed by injecting argon into the liquid steel through the up‐leg of the RH vessel. It was found that the circulation flow rate of steel in the RH degasser was increasing when the argon flow was being varied from 800 to 1,600 NL/min, which confirms the industrial findings.

The present computation could not use the energy equation to compute the swelling of the gas bubbles inside the chamber due to huge computing time requirement.

The present computation could compute realistically the circulation flow rate of water in a U tube when fired by a gas jet by using a two‐phase Eulerian model and hence this model can be effectively used for industrial applications where two‐phase flow comes into picture.

The original contribution of the paper is in the use of the state‐of the‐art Eulerian two‐phase flow model to predict circulation flow in an industrial size RH degasser.

Large strain model can be formulated in terms of the Lagrangian or the Eulerian frame. In this paper, the Eulerian type large strain models are studied. Numerical examples on the Lagrangian and Eulerian types large strain models are investigated and compared. It is found that the differences in the choice of large strain model under large strain and rotation problems are noticeable but not significant if small load step is used for analysis. Furthermore, we have also found that unsymmetrical formulation instead of symmetrical formulation should be adopted for Eulerian type large strain models.

The purpose of this paper is to compute the pressure drop through sudden expansions and contractions for two‐phase flow of oil/water emulsions.

Two‐phase computational fluid dynamics (CFD) calculations, using Eulerian–Eulerian model, are employed to calculate the velocity profiles and pressure drops across sudden expansions and contractions. The pressure losses are determined by extrapolating the computed pressure profiles upstream and downstream of the expansion/contraction. The oil concentration is varied over a wide range of 0‐97.3 percent by volume. The flow field is assumed to be axisymmetric and solved in two dimensions. The two‐dimensional equations of mass, momentum, volume fraction and turbulent quantities along with the boundary conditions have been integrated over a control volume and the subsequent equations have been discretized over the control volume using a finite volume technique to yield algebraic equations which are solved in an iterative manner for each time step. The realizable per phase k‐ ε turbulent model is considered to update the fluid viscosity with iterations and capture the individual turbulence in both the phases.

The contraction and expansion loss coefficients are obtained from the pressure loss and velocity data for different concentrations of oil–water emulsions. The loss coefficients for the emulsions are found to be independent of the concentration and type of emulsions. The numerical results are validated against experimental data from the literature and are found to be in good agreement.

The present computation could not use the surface tension forces and the energy equation due to huge computing time requirement.

The present computation could compute realistically the two‐phase pressure drop through sudden expansions and contractions by using a two‐phase Eulerian model and hence this model can be effectively used for industrial applications where two‐phase flow comes into picture.

The original contribution of the paper is in the use of the state‐of‐the‐art Eulerian two‐phase flow model to predict the velocity profile and pressure drop through industrial piping systems.

The purpose of this paper is to assess the blast‐mitigation potential and the protection ability of an air‐vacated buffer placed in front of a target structure under realistic combat‐theatre conditions.

The blast‐mitigation efficacy of the air‐vacated buffer concept is investigated computationally using a combined Eulerian‐Lagrangian (CEL) fluid‐structure interaction (FSI) finite‐element analysis.

The two main findings resulting from the present work are: the air‐vacated buffer concept yields significant blast‐mitigation effects; and the buffer geometry and vacated‐air material‐state parameters (e.g. pressure, mass density, etc.) may significantly affect the extent of the blast‐mitigation effect.

The main contribution of the present work is a demonstration of the critical importance of timely deployment of the buffer relative to the arrival of the incident wave in order to fully exploit the air‐vacated buffer concept.

The purpose of this paper is to perform the computational fluid dynamics (CFD) simulation with experimental validation to investigate the particle segregation effect in abrupt and smooth shapes circulating fluidized bed (CFB) risers.

The experimental investigations were carried out in lab-scale CFB systems and the CFD simulations were performed by using commercial software BARRACUDA. Special attention was paid to investigate the gas-particle flow behavior at the top of the riser with three different superficial velocities, namely, 4, 6 and 7.7 m/s. Here, a CFD-based noble simulation approach called multi-phase particle in cell (MP-PIC) was used to investigate the effect of traditional drag models (Wen-Yu, Ergun, Wen-Yu-Ergun and Richardson-Davidson-Harrison) on particle flow characteristics in CFB riser.

Findings from the experimentations revealed that the increase in gas velocity leads to decrease the mixing index inside the riser. Moreover, the solid holdup found more in abrupt riser than smooth riser at the constant gas velocity. Despite the more experimental investigations, the findings with CFD simulations revealed that the MP-PIC approach, which was combined with different drag models could be more effective for the practical (industrial) design of CFB riser. Well agreement was found between the simulation and experimental outputs. The simulation work was compared with experimental data, which shows the good agreement (<4%).

The experimental and simulation study performed in this research study constitutes an easy-to-use with different drag coefficient. The proposed MP-PIC model is more effective for large particles fluidized bed, which can be helpful for further research on industrial gas-particle fluidized bed reactors. This study is expected to give throughout the analysis of CFB hydrodynamics with further exploration of overall fluidization.

This paper aims to investigate the effects of different volume fractions of Al₂O₃-water nanofluid on flow and heat transfer under chaotic convection conditions in an L-shaped channel, comparing the difference of numerical simulation results between single-phase and Eulerian–Lagrangian models.

The correctness and accuracy of the two calculation models were verified by comparing with the experimental values in literature. An experimental model of the L-shaped channel was processed, and the laser Doppler velocimeter was used to measure the velocities of special positions in the channel. The simulated values were compared with the experimental results, and the correctness and accuracy of the simulation method were verified.

The calculated results using the two models are basically consistent. Under the condition of Reynolds number is 500, when the volume fractions of nanofluid range from 1% to 4%, the heat transfer coefficients simulated by single-phase model are 1.49%–25.80% higher than that of pure water, and simulated by Eulerian–Lagrangian model are 3.19%–27.48% higher than that of pure water. Meanwhile, the friction coefficients are barely affected. Besides, there are obvious secondary flow caused by lateral oscillations on the cross sections, and the appearance of secondary flow makes the temperature distributions uniform on the cross section and takes more heat away, thus the heat transfer performance is enhanced.

The originality of this work is to reveal the differences between single-phase and two-phase numerical simulations under different flow states. The combination of chaotic convection and nanofluid indicates the direction for further improving the heat transfer threshold.

To develop a numerical methodology to simulate the lost foam casting (LFC), including the gas back‐pressure effects.

Back‐pressure effects are due to the interactions of many physical processes. The strategy proposed herein tries to model all these processes within a simple formula. The main characteristic of the model consists of assuming that the back‐pressure is a known function of the external parameters (coating, temperature, gravity, etc.) that affects directly the heat transfer coefficient from the metal to the foam. The general framework of the simulation is a finite element model based on an arbitrary Lagrangian Eulerian (ALE) approach and the use of level set function to capture the metal front advance.

After experimental tunings, the model provides a way to include the back‐pressure effects in a simple way.

The method is not completely predictive in the sense that a priori tuning is necessary to calibrate the model.

Provides more realistic results than classical models.

The paper proposes a theoretical framework of a finite element method for the simulation of LFC process. The method uses an ALE method on a fixed mesh and a level‐set function to capture metal front advance. It proposes an original formula for the heat transfer coefficient that enables one to include back‐pressure effects.

Describes a tracer model, DREAM (the Danish Rimpuff and Eulerian Accidental release Model), developed for studying transport, dispersion, and deposition of air pollution caused by a single but strong source. The model is based on a combination of a Lagrangian short‐range puff model and a Eulerian long‐range transport model. It has been run and validated against measurements from the two European Tracer Experiment (ETEX) releases and from the Chernobyl accident. An air pollution forecast system, THOR, is under development, to make forecasts of various air pollutants on a European scale. Some preliminary results are shown. DREAM will be implemented in THOR for calculations of real time predictions of transport, dispersion and deposition of radioactive material from accidental releases (e.g. Chernobyl). Some applications of the DREAM model and examples of model results are described.