scholarly journals Modeling an Airlift Reactor for the Growing of Microalgae

2018 ◽  
Vol 12 (1) ◽  
pp. 80-94
Author(s):  
Gustavo A. Lara ◽  
Luis Moreno ◽  
Yendery Ramírez ◽  
Luis A. Cisternas
Keyword(s):  
Fluid Dynamics ◽  
Carbon Dioxide ◽  
Flow Dynamics ◽  
Airlift Reactor ◽  
Air Injection ◽  
Reactor Operation ◽  
Flow Rates ◽  
Injection Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Liquid Movement

Objective: The flow dynamics of an airlift reactor for the growing of microalgae is modeled using Computational Fluid Dynamics (CFD). The model is applied to the operation and optimization of the reactor, giving a valuable picture of the liquid movement and carbon dioxide trajectory at different air injection flow rates. Methods: A novel aspect of the model is that air and carbon dioxide are injected at separated locations. Air is injected at the bottom of the reactor and CO2 injection takes place in the downcomer region of the reactor to obtain longer CO2 paths, improving its transference. Results: The results show modeling is a useful tool in the control of the reactor operation; for example, in avoiding the sedimentation of microalgae or for detecting the existence of zones with extremely low CO2 concentrations.

Design Approach for the Development of the Flow Field of Bipolar Plates for a PEMFC Stack Prototype

2014 ◽  
Vol 11 (6) ◽  
Author(s):  
Paolo Sala ◽  
Paola Gallo Stampino ◽  
Giovanni Dotelli
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cell ◽  
Cfd Simulation ◽  
Bipolar Plates ◽  
Flow Rates ◽  
Gas Leakage ◽  
Auxiliary Power ◽  
Computational Fluid Dynamics Cfd ◽  
Enhance Mass

This work is part of a project whose final aim is the realization of an auxiliary power fuel cell generator. It was necessary to design and develop bipolar plates that would be suitable for this application. Bipolar plates have a relevant influence on the final performances of the entire device. A gas leakage or a bad management of the water produced during the reaction could be determinant during operations and would cause the failure of the stack. The development of the bipolar plates was performed in different steps. First, the necessity to make an esteem of the dynamics that happen inside the feeding channels led to perform analytical calculations. The values found were cross-checked performing a computational fluid dynamics (CFD) simulation; finally, it was defined the best pattern for the feeding channels, so that to enhance mass transport and achieve the best velocity profile. The bipolar plates designed were machined and assembled in a laboratory scale two cells prototype stack. Influences of the temperature and of the humidity were evaluated performing experiments at 60 deg and 70 deg and between 60% and 100% of humidity of the reactant gasses. The best operating point achieved in one of these conditions was improved by modifying the flow rates of the reactant, in order to obtain the highest output power, and it evaluated the reliability of the plates in experiments performed for longer times, at fixed voltages.

Consequence Study of Pressurized CO2 Release Containing Impurities with Obstacles

2014 ◽  
Vol 625 ◽  
pp. 474-477 ◽  
Author(s):  
Hoang Huy Phuoc Loi Pham ◽  
Risza Rusli ◽  
Mohd Zamri Abdullah
Keyword(s):  
Fluid Dynamics ◽  
Carbon Dioxide ◽  
Computational Fluid Dynamics ◽  
Hydrogen Sulfide ◽  
Suitable Method ◽  
Time Varying ◽  
Fatality Rate ◽  
Release Area ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Cloud

A rupture or puncture of a carbon dioxide (CO2) pipeline will result in a release of dense CO2 gas cloud mixed with toxic impurities such as hydrogen sulfide (H2S) to the ambience. This paper has proposed an approach for developing an accurate consequence model for CO2 release containing H2S in order to demonstrate a safe layout and other safeguards. Thus, a validated code using computational fluid dynamics (CFD) was applied to predict time-varying concentrations of CO2 and H2S at a point of downwind release area. Then overall fatality rate due to both CO2 and H2S has been estimated at this point. Results indicate that this is a suitable method for assessing the consequences of the release of CO2 via pipeline leakage.

Airflow and Cooling in a Data Center

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Suhas V. Patankar
Keyword(s):  
Fluid Dynamics ◽  
Data Center ◽  
Cfd Simulations ◽  
Flow Rates ◽  
Factors Affecting ◽  
Hot Air ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd ◽  
Cooling Air ◽  
Insight Into

This paper deals with the distribution of airflow and the resulting cooling in a data center. First, the cooling challenge is described and the concept of a raised-floor data center is introduced. In this arrangement, cooling air is supplied through perforated tiles. The flow rates of the cooling air must meet the cooling requirements of the computer servers placed next to the tiles. These airflow rates are governed primarily by the pressure distribution under the raised floor. Thus, the key to modifying the flow rates is to influence the flow field in the under-floor plenum. Computational fluid dynamics (CFD) is used to provide insight into various factors affecting the airflow distribution and the corresponding cooling. A number of ways of controlling the airflow distribution are explored. Then attention is turned to the above-floor space, where the focus is on preventing the hot air from entering the inlets of computer serves. Different strategies for doing this are considered. The paper includes a number of comparisons of measurements with the results of CFD simulations.

Three-Dimensional CFD Analysis of Gas Mixing in Large Volumes

2001 ◽  
Author(s):  
Brian L. Smith
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Three Dimensional ◽  
Air Injection ◽  
Cfd Analysis ◽  
Gas Mixing ◽  
Air Mixing ◽  
Computational Fluid Dynamics Cfd ◽  
Pure Steam

Abstract The paper describes three-dimensional Computational Fluid Dynamics (CFD) calculations undertaken in support of analyses of steam/air mixing which takes place in the drywell volumes of the 1/40th-scale ESBWR1 mock-up facility PANDA under conditions of symmetric steam/air injection and asymmetric outflow. Steady-state simulations for pure steam conditions illustrate how the flow streams mix to ensure balanced outflow conditions to the condensers. A transient calculation has also been performed to examine how air released from solution in the PANDA boiler would ultimately accumulate in the separate condenser units. Results provide a possible explanation for the rundown in performance of one of the condensers which was repeatedly observed in some of the PANDA tests.

CFD Challenge: Modeling Blood Flow Dynamics in a Cerebral Aneurysm Using Fluent

2012 ◽  
Author(s):  
Nicholas Shaffer ◽  
Francis Loth
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Fluid Motion ◽  
Flow Dynamics ◽  
Cfd Modeling ◽  
Blood Flow Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
The University

The Biofluids Laboratory at the University of Akron has used Fluent [Ansys Inc., Canonsburg, PA] for image-based computational fluid dynamics (CFD) modeling of physiological flows since the lab’s inception in 2008. Recently our group has focused on modeling of pathophysiological problems in cerebrospinal fluid motion and air flow in the trachea, in addition to past work in cardiovascular problems.

scholarly journals Investigation of the Effect of Ski Jump on the Flow Dynamics around Generic Aircraft Carrier

2021 ◽  
Vol 71 (2) ◽  
pp. 296-303
Author(s):  
Rahul Thakur ◽  
K. Vignesh Kumar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Degrees Of Freedom ◽  
Flow Dynamics ◽  
Aircraft Carrier ◽  
Six Degrees Of Freedom ◽  
The Past ◽  
Turbulent Airflow ◽  
Computational Fluid Dynamics Cfd ◽  
Flight Deck

The landing operation on an aircraft carrier is a complicated and risky process. Unlike land-based operations, the landing area available on carriers is in continuous motion in all the six degrees of freedom. The ski jump, flight deck, hull, and superstructure of the carrier interact with the oncoming wind’s flow-field which creates a turbulent airflow behind the carrier. This ‘burble effect’ is very dangerous and has caused various mishaps in the past. To complement the work being undertaken at IIT Delhi to study the flow dynamics in the carrier environment, the present study investigates the effect of ski jump and superstructure on the flow around the generic aircraft carrier (GAC). Computational fluid dynamics (CFD) studies are undertaken to simulate the airwake and establish a baseline with the ski jump. Subsequently, further studies are carried out to analyse the sensitivity of the wake to changes in carrier geometry. The introduction of the ski generates a major proportion of turbulence encountered in the aft by the approaching pilot. This is reduced significantly by optimising ski jump geometry in various ways.

Airflow Modeling and Simulation Required in CBRN Collective Protection Design

2016 ◽  
Vol 22 (3) ◽  
pp. 649-653 ◽  
Author(s):  
Claudiu Lăzăroaie ◽  
Teodora Zecheru ◽  
Ciprian Său ◽  
Tudor Cherecheş
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Flow Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Strategic Position ◽  
Industrial Materials ◽  
Materials Used ◽  
Commercial Applications ◽  
Air Circulation

Abstract Many CBRN agents are very difficult to detect and identify, due to the fact that most technologies, equipment and materials used for their obtainment have also commercial applications. One possibility to counteract such threats, both for military and civilians, is to use systems of collective protection (COLPRO), which must be manufactured from materials that can withstand not only the action of CBRN agents, but, as much as possible, toxic industrial materials (TIMs). The computational fluid dynamics (CFD) study of the atmosphere in the neighbourhood of the COLPRO tent and the air flow dynamics inside the tent give all the necessary data regarding the effect of air circulation on the entire COLPRO system. Based on this study, a favourable orientation of the COLPRO tent may be established relatively to the strategic position of the troops or the civilian groups, versus statistical wind speed, direction and charge.

Application of computational fluid dynamics technique to storage reservoir studies

1998 ◽  
Vol 37 (2) ◽  
pp. 219-226 ◽  
Author(s):  
C. T. Ta ◽  
W. J. Brignal
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Residence Time ◽  
Horizontal Plane ◽  
Plug Flow ◽  
Flow Dynamics ◽  
Wind Condition ◽  
Time Simulation ◽  
Computational Fluid Dynamics Cfd ◽  
Installation Cost

The flow dynamics in Grimsbury reservoir is studied using Computational Fluid Dynamics (CFD). Under no wind condition, flows circulate in the horizontal plane. These circulations, in general, lead to short circuiting and zones of stagnation. Modifications to the inlet and the outlet are investigated to maximise the residence time. They include the manifold inlet arrangement, the submerged baffle inlet and the central outlet arrangement. The results of the residence time simulation indicate that the manifold inlet option gives the best ‘plug-flow’ efficiency, next the submerged baffle option and finally the central outlet option. The submerged baffle inlet option, however, is considered to be the preferred option because of its low installation cost and because of the reasonable balance between the degree of mixing and the residence time.

Heat Storage Performance of a Honeycomb Ceramic Monolith

2014 ◽  
Vol 7 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Xiaoni Qi ◽  
Yongqi Liu
Keyword(s):  
Fluid Dynamics ◽  
Thermal Process ◽  
Heat Storage ◽  
Three Dimensional ◽  
Regenerative Process ◽  
Flow Rates ◽  
Storage Performance ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Honeycomb Ceramic

Honeycomb ceramic is the key component of the regenerative system. The three-dimensional numerical model has been established for thermal process in honeycomb regenerator. The numerical simulation was performed using FLUENT, a commercial computational fluid dynamics (CFD) code, to compare simulation results to the test data. The regenerative process of a honeycomb ceramic regenerator was simulated under different conditions. The results under different flow rates, different flowing time, different materials and different wall thickness were investigated. The work in this paper provides a theory basis and guide to the exploitation and appliance of HTAC system and the results of the numerical calculation can be used as the foundation of engineering design. The results may be utilized for design of porous media reactors and process optimization.

scholarly journals A Numerical and Experimental Analysis of Flow in a Centrifugal Pump

2002 ◽  
Author(s):  
M. T. Stickland ◽  
T. J. Scanlon ◽  
J. Ferna´ndez-Francos ◽  
E. Blanco-Marigorta ◽  
J. Parrondo
Keyword(s):  
Fluid Dynamics ◽  
Particle Image ◽  
Mirror Image ◽  
Centrifugal Impeller ◽  
Cfd Model ◽  
Flow Rates ◽  
Blade Passage ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd ◽  
Relative Flow

This paper describes the use of a rotating all mirror image derotator system in collaboration with Particle Image Velocimetry (PIV) to visualise and quantitatively examine the flow patterns between the blades of a centrifugal impeller. The authors have been able to obtain the relative velocities in a centrifugal impeller at rotational speeds between 300 and 600 revs per minute with water flow rates between 450 and 900 litres per hour. Velocity contours and vector maps of the relative flow field within a blade passage are presented for an impeller speed of 350 rpm and a flow rate of 510 l/h. The data are compared with the results of a computational fluid dynamics (CFD) model.

Sign in / Sign up

Export Citation Format

Share Document