Effect of Interfacial Tension on the Emulsification of Slag - Considerations on the CFD Modelling of Dispersion

2013 ◽  
Vol 762 ◽  
pp. 242-247 ◽  
Author(s):  
Petri Sulasalmi ◽  
Ville Valtteri Visuri ◽  
Timo Fabritius
Keyword(s):  
Interfacial Tension ◽  
Droplet Diameter ◽  
Slag Layer ◽  
Phase System ◽  
Cfd Modelling ◽  
Factors Affecting ◽  
Significant Phenomenon ◽  
Dominant Property ◽  
Computational Fluid Dynamics Cfd ◽  
Top Slag

Top slag emulsification is a significant phenomenon in refining metallurgy. During bottom-or side-blowing, the flowing steel detaches small droplets from the top slag. The interfacial energy between liquid slag and steel is one of the most important factors affecting to emulsification. Surface energy, which can be described by interfacial tension, is the dominant property when determining slag emulsification. During chemical reactions, mass transfer between the phases decreases the interfacial tension at the slag-steel interface. The change in the interfacial tension affects the droplet formation.In this paper, the effect of interfacial tension on the emulsification was studied with Computational Fluid Dynamics (CFD) modelling. Three cases were simulated by considering a 3-phase system consisting of slag, steel and gas. A small area, where a 15 mm slag layer lies on top of the liquid steel, was simulated applying three different interfacial tensions, while keeping other properties unaltered. Gas was included to enable a free slag top-surface. The droplet diameter, size distribution and amount of droplets are in the scope of interest. It was found that the Sauter mean diameter of the slag droplets increased as the interfacial tension increased. The emulsification fraction varied between 1.621.95%.

Characterisation of Cell Adhesion to Substrate Materials and the Resistance to Enzymatic and Mechanical Cell-Removal

2008 ◽  
Vol 1097 ◽  
Author(s):  
Helen Jane Griffiths ◽  
John G Harvey ◽  
James Dean ◽  
James A Curran ◽  
Athina E Markaki ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cell Adhesion ◽  
Liquid Flow ◽  
Adhesive Strength ◽  
Cell Detachment ◽  
Shear Forces ◽  
Cfd Modelling ◽  
Computational Fluid Dynamics Cfd

AbstractCell-implant adhesive strength is important for prostheses. In this paper, an investigation is described into the adhesion of bovine chondrocytes to Ti6Al4V-based substrates with different surface roughnesses and compositions. Cells were cultured for 2 or 5 days, to promote adhesion. The ease of cell removal was characterised, using both biochemical (trypsin) and mechanical (accelerated buoyancy and liquid flow) methods. Computational fluid dynamics (CFD) modelling has been used to estimate the shear forces applied to the cells by the liquid flow. A comparison is presented between the ease of cell detachment indicated using these methods, for the three surfaces investigated.

Application of Computational Fluid Dynamics Simulations to the Analysis of Bank Effects in Restricted Waters

2009 ◽  
Vol 62 (3) ◽  
pp. 477-491 ◽  
Author(s):  
D. C. Lo ◽  
Dong-Taur Su ◽  
Jan-Ming Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Modelling ◽  
Bank Effect ◽  
Force Increase ◽  
Computational Fluid Dynamics Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamics Simulations ◽  
Yaw Angle ◽  
Vessel Speed

It is well known that vessels operating in the vicinity of a lateral bank experience a significant yaw moment and sway force. This bank effect has a major impact on the manoeuvring properties of the vessel and must therefore be properly understood to ensure the safe passage of the vessel through the restricted waterway. Accordingly, this study performs a series of simulations using commercial FLOW-3D® computational fluid dynamics (CFD) software and the KRISO 3600 TEU container ship model to examine the effects of the vessel speed and distance to bank on the magnitude and time-based variation of the yaw angle and sway force. The results show that for a given vessel speed, the yaw angle and sway force increase as the distance to bank reduces, while for a given distance between the ship and the bank, the yaw angle and sway force increase with an increasing vessel speed. In addition, it is shown that even when a vessel advances at a very low speed, it experiences a significant bank effect when operating in close vicinity to the bank. Overall, the results presented in this study confirm the feasibility of the CFD modelling approach as a means of obtaining detailed insights into the bank effect without the need for time-consuming and expensive ship trials.

scholarly journals A Review of CFD Modelling and Performance Metrics for Osmotic Membrane Processes

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 285
Author(s):  
Kang Yang Toh ◽  
Yong Yeow Liang ◽  
Woei Jye Lau ◽  
Gustavo A. Fimbres Weihs
Keyword(s):  
Performance Metrics ◽  
Forward Osmosis ◽  
Cfd Modelling ◽  
Membrane Processes ◽  
Pressure Retarded Osmosis ◽  
Multi Scale ◽  
Scale Modelling ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance ◽  
Module Performance

Simulation via Computational Fluid Dynamics (CFD) offers a convenient way for visualising hydrodynamics and mass transport in spacer-filled membrane channels, facilitating further developments in spiral wound membrane (SWM) modules for desalination processes. This paper provides a review on the use of CFD modelling for the development of novel spacers used in the SWM modules for three types of osmotic membrane processes: reverse osmosis (RO), forward osmosis (FO) and pressure retarded osmosis (PRO). Currently, the modelling of mass transfer and fouling for complex spacer geometries is still limited. Compared with RO, CFD modelling for PRO is very rare owing to the relative infancy of this osmotically driven membrane process. Despite the rising popularity of multi-scale modelling of osmotic membrane processes, CFD can only be used for predicting process performance in the absence of fouling. This paper also reviews the most common metrics used for evaluating membrane module performance at the small and large scales.

scholarly journals A Methodology for Modelling of Steady State Flow in Pelton Turbine Injectors

2019 ◽  
Vol 15 (2) ◽  
pp. 246-255
Author(s):  
Tri Ratna Bajracharya ◽  
Rajendra Shrestha ◽  
Ashesh Babu Timilsina
Keyword(s):  
Velocity Profile ◽  
High Speed ◽  
Three Dimensional ◽  
Maximum Error ◽  
Cfd Modelling ◽  
Pelton Turbine ◽  
Short Period ◽  
Computational Fluid Dynamics Cfd ◽  
Jet Velocity ◽  
Nozzle Opening

 Pelton turbine is a high head-impulse type turbine. The high-speed jet strikes the symmetrical semi ellipsoidal buckets, thus transferring the momentum within short period of time, impulse. The conversion of potential energy of water to kinetic energy in the form of jet is done by a nozzle with internally fitted spear or needle, the assembly in known as injector. The jet quality includes but is not limited to jet velocity, velocity distribution ‘velocity profile’, core location etc. In this study, the modeling of flow in Pelton turbine injector is done by commercial Computational Fluid Dynamics (CFD) solver on a three-dimensional flow domain. The results obtained from CFD modelling are then compared against the experimental observations and previously published literatures. The jet streamline, jet velocity profile and jet core location are then studied. As observed experimentally, the mean jet diameter reduces as the nozzle opening decreases. In addition, like the experimental observations, the jet first contracts and then expands. The diameter of the contraction is then normalized with nozzle exit diameter and is plotted for both experimental observations as well as the results of the numerical simulation. The maximum error between experimental and numerical analysis of jet contraction is 20%. The jet core is located at region axially ahead of needle tip.

Residence time study of a hydrodynamic vortex separator applied to predicting disinfection performance

2009 ◽  
Vol 223 (3) ◽  
pp. 113-122 ◽  
Author(s):  
T O'Doherty ◽  
D A Egarr ◽  
M G Faram ◽  
I Guymer ◽  
N Syred
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Residence Time ◽  
Treated Wastewater ◽  
Time Study ◽  
Cfd Modelling ◽  
Computational Fluid Dynamics Cfd ◽  
Vortex Separator ◽  
Theoretical Performance

The fluid residence time characterization of a 3.4 m diameter hydrodynamic vortex separator (HDVS) has been carried out under laboratory conditions. Computational fluid dynamics (CFD) modelling has then been undertaken for the same conditions at which the experimental data were collected and validated against the experimental results, for which reasonable correspondence has been found. Using the results from the CFD modelling and batch inactivation results from the disinfection of secondary treated wastewater, it is shown that the theoretical performance of an HDVS as a contact vessel for disinfection can be determined and the practical applicability of an HDVS for disinfection is confirmed.

CFD Modelling of Multiphase Flows: An Overview

2003 ◽  
Author(s):  
Rajnish K. Calay ◽  
Arne E. Holdo
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Mathematical Models ◽  
Cfd Modelling ◽  
Two Phase ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Modeling Of Flows

The Computational Fluid Dynamics (CFD) is now increasingly being used for modeling industrial flows, i.e. flows which are multiphase and turbulent. Numerical modeling of flows where momentum, heat and mass transfer occurs at the interface presents various difficulties due to the wide range of mechanisms and flow scenarios present. This paper attempts to provide a summary of available mathematical models and techniques for two-phase flows. Some comments are also made on the models available in the commercially available codes.

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