Efficiency prediction for storage chambers using computational fluid dynamics

1996 ◽  
Vol 33 (9) ◽  
pp. 163-170 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Particle Tracking ◽  
Critical Value ◽  
Complex Geometries ◽  
Bed Shear Stress ◽  
Breadth Ratio ◽  
Computational Fluid Dynamics Cfd ◽  
Simulated Flow

Research was undertaken in order to identify possible methodologies for the prediction of sedimentation in storage chambers based on computational fluid dynamics (CFD). The Fluent CFD software was used to establish a numerical model of the flow field, on which further analysis was undertaken. Sedimentation was estimated from the simulated flow fields by two different methods. The first approach used the simulation to predict the bed shear stress distribution, with deposition being assumed for areas where the bed shear stress fell below a critical value (τcd). The value of τcd had previously been determined in the laboratory. Efficiency was then calculated as a function of the proportion of the chamber bed for which deposition had been predicted. The second method used the particle tracking facility in Fluent and efficiency was calculated from the proportion of particles that remained within the chamber. The results from the two techniques for efficiency are compared to data collected in a laboratory chamber. Three further simulations were then undertaken in order to investigate the influence of length to breadth ratio on chamber performance. The methodology presented here could be applied to complex geometries and full scale installations.

scholarly journals Computational fluid dynamics for enhanced tracheal bioreactor design and long-segment graft recellularization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hankyu Lee ◽  
Alba E. Marin-Araujo ◽  
Fabio G. Aoki ◽  
Siba Haykal ◽  
Thomas K. Waddell ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Particle Tracking ◽  
Lessons Learned ◽  
Cell Seeding ◽  
Fluid Delivery ◽  
Tracking Model ◽  
Graft Success ◽  
Hydrodynamic Environment

AbstractSuccessful re-epithelialization of de-epithelialized tracheal scaffolds remains a challenge for tracheal graft success. Currently, the lack of understanding of the bioreactor hydrodynamic environment, and its relation to cell seeding outcomes, serve as major obstacles to obtaining viable tracheal grafts. In this work, we used computational fluid dynamics to (a) re-design the fluid delivery system of a trachea bioreactor to promote a spatially uniform hydrodynamic environment, and (b) improve the perfusion cell seeding protocol to promote homogeneous cell deposition. Lagrangian particle-tracking simulations showed that low rates of rotation provide more uniform circumferential and longitudinal patterns of cell deposition, while higher rates of rotation only improve circumferential uniformity but bias cell deposition proximally. Validation experiments with human bronchial epithelial cells confirm that the model accurately predicts cell deposition in low shear stress environments. We used the acquired knowledge from our particle tracking model, as a guide for long-term tracheal repopulation studies. Cell repopulation using conditions resulting in low wall shear stress enabled enhanced re-epithelialization of long segment tracheal grafts. While our work focuses on tracheal regeneration, lessons learned in this study, can be applied to culturing of any tissue engineered tubular scaffold.

scholarly journals Brownout Simulations of Model-Rotors In Ground Effect

2020 ◽  
Vol 314 ◽  
pp. 01006
Author(s):  
F. Rovere ◽  
G.N. Barakos ◽  
R. Steijl
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Particle Tracking ◽  
Ground Effect ◽  
Experimental Results ◽  
Safety Studies ◽  
Effect Time ◽  
Particle Paths ◽  
Simulated Flow

In this work computational fluid dynamics is used to validate experimental results for a two-bladed small rotor In Ground Effect conditions. The paper focuses on the evaluation and prediction of the rotor outwash generated in ground effect. Time-averaged outflow velocities are compared with experimental results, and the simulated flow field is used for safety studies using the PAXman model and particle tracking methods. The aircraft weights have been studied, evaluating scaling factors to define how helicopter weight can affect the outflow forces and the particle paths. Results show how the wake generated by heavier helicopters can lead to stronger forces on ground personnel and push the particles farther away from the rotor.

Air Pressure Reducer Modeling by CFD Methodology

2014 ◽  
Vol 960-961 ◽  
pp. 547-550
Author(s):  
Ran Ran Wu ◽  
Ding Fan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Turbulence Model ◽  
Physical Experiment ◽  
Air Pressure ◽  
Pressure Characteristic ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement ◽  
Pressure Characteristics

In this paper, the computational fluid dynamics (CFD) methodology as well as the shear-stress transport (SST) k-omega turbulence model was adopted to model the air pressure reducer (APR). Changing the gas needle’s displacement of APR continuously, the writer obtains the displacement-pressure characteristics of APR. In order to demonstrate the validity of these characteristics, a physical experiment was conducted, which generates another displacement-pressure characteristic. Comparing the two characteristics with a good agreement, it is indicated that the CFD methodology is suitable to study the displacement-pressure characteristics of APR.

scholarly journals ANALISA PERFORMA HIDRO-TURBIN CROSS-FLOW DENGAN SUDUT DIAMETER RUNNER 10° DAN JUMLAH SUDU 8, 16, DAN 24 MENGGUNAKAN METODE CFD

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Muhammad Mu'izzul As'ad ◽  
Ahmad Janan Febrianto ◽  
Dandun Mahesa Prabowoputra
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Renewable Energy ◽  
Angular Velocity ◽  
Cross Flow ◽  
Shear Stress Transport ◽  
Computational Fluid Dynamics Cfd

Hidro turbin adalah salah satu komponen utama pada pembangkit listrik tenaga air. Penelitian terhadap turbin air memiliki peran penting dalam pengembangan renewable energy yang bersumber dari tenaga hidro. Dimana Indonesia memiliki potensi sumber energi hidro yang sangat besar. Hidro-turbin memiliki beberapa jenis yaitu turbin Sumbu Horizontal, Turbin Sumbu vertical dan turbin Cross-Flow. Penelitian ini dilakukan pada turbin air tipe Cross-Flow, dan dilakukan dengan metode Computational Fluid Dynamics (CFD). Simulasi dilakukan secara tiga dimensi dan menggunakan perangkat lunak Ansys Student 2021 dengan solver CFX. Turbin cross-flow menggunakan runner dengan sudut 10°, dengan variasi jumlah sudu 8, 16, dan 24. Penelitian ini bertujuan untuk mengetahui performa turbin Cross-flow dan mengetahui pengaruh jumlah sudu pada performa tersebut. Turbin Cross-flow beroperasi pada kecepatan fluida 3m/s dan angular velocity 50-250 rpm. Simulasi menggunakan tipe turbulensi Shear Stress Transport dalam kondisi tunak, Hasil menunjukan turbin cross-flow dengan sudut runner 10o dan jumlah sudu 24 memiliki performa terbaik bila dibandingkan dengan jumlah sudu 8 dan 16.

A computational fluid dynamics (CFD) particle tracking approach to efficiency prediction

1998 ◽  
Vol 37 (1) ◽  
pp. 285-293 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Tracking ◽  
Urban Pollution ◽  
Storage Tanks ◽  
Storage Chamber ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Parameters ◽  
Injection Location ◽  
Selection Of

Storage chambers play an important role in urban pollution management. They are frequently used in conjunction with CSO structures, where they reduce the number and magnitude of CSO spill events. However, one problem associated with the use of storage tanks at CSOs is the deposition of sediment. Techniques which enable engineers to design such chambers for minimal deposition are required. In this paper the use of the particle tracking routine contained within the Fluent computational fluid dynamics (CFD) software for the prediction of sediment deposition in storage chambers is described. The paper details the way in which the particle tracking routine was configured to produce realistic efficiency results for the comparison of storage chamber performance. Consideration was given to the physical characteristics of the sediment, the injection location, the boundary conditions and a number of relevant simulation parameters. The sensitivity of efficiency prediction to the selection of these parameters is emphasised. The paper also demonstrates the potential application of particle tracking to the prediction of probable deposit locations.

scholarly journals A Computational Fluid Dynamics Protocol for The Hemodynamic Analysis of a Microfluidic Model of Thrombosis

2021 ◽  
Author(s):  
Yunduo Charles Zhao ◽  
Sarah Elizabeth Keogh ◽  
Parham Vatankhah ◽  
Renee Ellen Preketes-Tardiani ◽  
Lining Arnold Ju
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Experimental Analysis ◽  
Microfluidic Channels ◽  
Cfd Simulations ◽  
Disturbed Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Time Observation ◽  
Real Time Observation

Abstract Thrombosis is both attributed to biochemical agonists and mechanical stresses applied to platelets. Whilst the effect of biochemical agonists has been extensively studied, the mechanosensitive factors remain poorly defined. Stenotic microfluidic channels mimic the narrowing vessels, providing the real-time observation of platelets under disturbed flow. Though the experimental analysis of platelets in disturbed flow confirms the mechanosensitive behavior of platelets, it cannot explicate detailed thresholds for platelet activation. Computational Fluid Dynamics (CFD) could be utilized alongside experimental analysis to characterize thresholds for platelet behavior under imposed shear stress. CFD simulations, however, are prone to uncertainties and errors which should be minimized to obtain compelling results. Hereby, we have presented a CFD protocol for researchers in the field of microfluidic and hemodynamic studies.

scholarly journals Computational fluid dynamic analysis reveals the underlying physical forces playing a role in 3D multiplex brain organoid cultures

2018 ◽  
Author(s):  
Livia Goto-Silva ◽  
Nadia M. E. Ayad ◽  
Iasmin L. Herzog ◽  
Nilton P. Silva ◽  
Bernard Lamien ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Suspension Culture ◽  
Fluid Dynamic ◽  
Spinner Flask ◽  
List Type ◽  
Computational Fluid Dynamic Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Brain Organoid

AbstractOrganoid cultivation in suspension culture requires agitation at low shear stress to allow for nutrient diffusion, which preserves tissue structure. Multiplex systems for organoid cultivation have been proposed, but whether they meet similar shear stress parameters as the regularly used spinner flask and its correlation with the successful generation of brain organoids, has not been determined. Herein, we used computational fluid dynamics (CFD) analysis to compare two multiplex culture conditions: steering plates on an orbital shaker and the use of a previously described bioreactor. The bioreactor had low speed and high shear stress regions that may affect cell aggregate growth, depending on volume, whereas the CFD parameters of the steering plates were closest to the parameters of the spinning flask. Our protocol improves the initial steps of the standard brain organoid formation, and organoids produced therefrom displayed regionalized brain structures, including retinal pigmented cells. Overall, we conclude that suspension culture on orbital steering plates is a cost-effective practical alternative to previously described platforms for the cultivation of brain organoids for research and multiplex testing.HighlightsImprovements to organoid preparation protocolMultiplex suspension culture protocol successfully generate brain organoidsComputational fluid dynamics (CFD) reveals emerging properties of suspension culturesCFD of steering plates is equivalent to that of spinner flask cultures

scholarly journals Computational Fluid Dynamics (CFD) Investigation of Aerodynamic Characters inside Nasal Cavity towards Surgical Treatments for Secondary Atrophic Rhinitis

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Ya Zhang ◽  
Xudong Zhou ◽  
Miao Lou ◽  
Minjie Gong ◽  
Jingbin Zhang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Atrophic Rhinitis ◽  
Nasal Resistance ◽  
Septal Perforation ◽  
Virtual Operation ◽  
Nasal Floor ◽  
Computational Fluid Dynamics Cfd ◽  
Surgical Treatments

Purpose. To use computational fluid dynamics (CFD) technology to fundamentally understand (1) the effect of surgical treatments on nasal physiology for secondary atrophic rhinitis and (2) the priority of operations. Subjects and Methods: With the aid of medical imaging and CFD modeling, three virtual operations (nasoseptal perforation repair, cavity narrowing, and a combination of both) were performed to analyze airflow, nasal resistance, and wall shear stress. Results. Compared with the cavity-narrowing virtual operation, nasal resistance was not significantly altered by septal perforation repair virtual operation. Airflow allocation changed with more air flowing through the olfactory area and less though the nasal floor after all operations, especially the cavity-narrowing operation. Wall shear stress at the original epistaxis area and the nasal floor was reduced after the cavity-narrowing operation. Conclusions. Simulation results suggest that the cavity-narrowing operation takes priority over septal perforation repair if a staged surgery approach is adopted. If only one operation can be chosen, the cavity-narrowing operation is better than the septal perforation repair. This work shows that CFD-based modeling may aid precision medicine.

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