Sliding mesh computational fluid dynamics—a predictive tool in stirred tank design

1997 ◽  
Vol 211 (3) ◽  
pp. 149-156 ◽  
Author(s):  
Z Jaworski ◽  
M L Wyszynski ◽  
I P T Moore ◽  
A W Nienow
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Initial Conditions ◽  
Integrated Design ◽  
Flow Characteristics ◽  
Cfd Modelling ◽  
Predictive Tool ◽  
Sliding Mesh ◽  
Tank Design ◽  
Experimental Values

The use of a fully predictive numerical model of flow in a stirred, baffled tank is presented and validated for the laminar flow regime. This approach employs a commercial computational fluid dynamics (CFD) package with sliding mesh facility. The comparison of computed and experimental values for various flow characteristics shows a very good agreement without the need to input any experimental values for the boundary or initial conditions. It is proposed that the model/experiment error ratio (involving relative errors) may be generally adopted as a criterion for the quality of CFD modelling. This ratio should not be much larger, and does not need to be smaller, than unity. The ratio obtained in this work was just over unity. The state of the art CFD packages are now believed to be able to form a suitable basis for the process engineering aspects of an integrated design of stirred tanks, including mechanical engineering and other related issues.

Computational fluid dynamics modelling of hydraulics and sedimentation in process reactors during aeration tank settling

2006 ◽  
Vol 53 (12) ◽  
pp. 257-264 ◽  
Author(s):  
M.D. Jensen ◽  
P. Ingildsen ◽  
M.R. Rasmussen ◽  
J. Laursen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Control Method ◽  
Waste Water Treatment ◽  
Aeration Tank ◽  
Cfd Modelling ◽  
Design Changes ◽  
Dynamics Modelling ◽  
Tank Design ◽  
Tank Settling

Aeration tank settling is a control method allowing settling in the process tank during high hydraulic load. The control method is patented. Aeration tank settling has been applied in several waste water treatment plants using the present design of the process tanks. Some process tank designs have shown to be more effective than others. To improve the design of less effective plants, computational fluid dynamics (CFD) modelling of hydraulics and sedimentation has been applied. This paper discusses the results at one particular plant experiencing problems with partly short-circuiting of the inlet and outlet causing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in the process tank. The model has allowed us to establish a clear picture of the problems arising at the plant during aeration tank settling. Secondly, several process tank design changes have been suggested and tested by means of computational fluid dynamics modelling. The most promising design changes have been found and reported.

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.

Fish-friendly design of an axial flow pump impeller based on a blade strike model

2019 ◽  
Vol 234 (2) ◽  
pp. 173-186 ◽  
Author(s):  
Qiang Pan ◽  
Weidong Shi ◽  
Desheng Zhang ◽  
BPM van Esch ◽  
Ruijie Zhao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Behavior ◽  
Integrated Design ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Fish Mortality ◽  
Computational Fluid Dynamics Analysis ◽  
Axial Flow Pump ◽  
Flow Pump

With environmental awareness growing in many countries, governments are taking measures to reduce mortality of migrating fish in pumping stations. Manufacturers seek to develop pumps that are less damaging to fish and still provide good hydraulic performance, but little is known about the implications design modifications may have on internal flow characteristics and overall hydraulic performance. In this paper, an integrated design method is proposed that combines a validated blade strike model for fish damage and a computational fluid dynamics method to assess the pump performance. A redesign of an existing, conventional, axial flow pump is presented as an example in this paper. It shows how the design of the impeller blades was modified stepwise in order to reduce fish mortality while its hydraulic performance was monitored. Computational fluid dynamics analysis of the flow near the hub of the highly skewed blades indicated that unconventional design modifications were required to ensure optimum flow behavior. In the final fish-friendly design, the risk of fish mortality has reduced considerably while the hydraulic performance of the pump is still acceptable for practical application.

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.

Wind Tunnel Testing and Computational Fluid Dynamics Analysis of a Wing-in-Ground Effect Vehicle

2007 ◽  
Author(s):  
Boonseng Soh ◽  
Andrew Low ◽  
Cees Bil ◽  
Brendon Bobbermien
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Ground Effect ◽  
Wind Tunnel Testing ◽  
Cfd Modelling ◽  
Aerodynamic Analysis ◽  
Computational Fluid Dynamics Analysis ◽  
Wing In Ground Effect ◽  
Tunnel Testing

The Wing-in-Ground Effect Concept Technology Demonstrator (WIGE CTD) project is a joint venture between Advanced Aerosystem Technologies Pty Ltd and RMIT University, aiming to design, validate and build a prototype recreational vehicle to fly two passengers over a distance of 500km at approximately 120km/h. The WIGE vehicle will fly very close to the surface, usually water, taking advantage of ground effect to transport passengers with a greater lift/drag ratio, and thus greater fuel-efficiency than conventional aircraft. Following preliminary design, an aerodynamic analysis of the vehicle was performed using wind tunnel testing and Computational Fluid Dynamics (CFD). This paper describes the methods used for wind tunnel testing and CFD modelling of the WIGE CTD design. Results obtained using the two approaches are compared with the aim of validating the CFD model and the techniques used in both wind tunnel and CFD modelling for use in future analyses. In addition to the aerodynamic analysis, a basic CFD prediction of the maximum hydrodynamic drag experienced during take off was attempted using a simple model of the WIGE vehicle hull. This result is required in order to ensure that the aquatic take off required by WIGE vehicles was possible for the design. Concurrently, the feasibility of using a general-purpose CFD solver like Fluent to analyse hull performance was also evaluated through this aspect of the investigation.

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