Manufacturing and Computational Fluid Dynamics Modeling of a Patient-Specific Fistula Model

2017 ◽  
Author(s):  
Yang Liu ◽  
Yihao Zheng ◽  
John Pitre ◽  
William Weitzel ◽  
Joseph Bull ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Patient Specific ◽  
Cfd Model ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Venous Wall ◽  
Good Agreement

Arteriovenous fistula is the joining of an artery to a vein to create vascular access for dialysis. The failure or maturation of fistula is affected by the vessel wall shear stress (WSS), which is difficult to measure in clinic. A computational fluid dynamics (CFD) model was built to estimate WSS of a patient-specific fistula model. To validate this model, a silicone phantom was manufactured and used to carry out a particle imaging velocimetry (PIV) experiment. The flow field from the PIV experiment shows a good agreement with the CFD model. From the CFD model, the highest WSS (40 Pa) happens near the anastomosis. WSS in the vein is larger than that in the artery. WSS on the outer venous wall is larger than that on the inner wall. The combined technique of additive manufacturing, silicone molding, and CFD is an effective tool to understand the maturation mechanism of a fistula.

Review of the Computational Fluid Dynamics Modeling of Fuel Cells

2005 ◽  
Vol 2 (4) ◽  
pp. 246-257 ◽  
Author(s):  
L. Ma ◽  
D. B. Ingham ◽  
M. Pourkashanian ◽  
E. Carcadea
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Computational Fluid Dynamics Cfd ◽  
Exchange Membrane

This paper presents a review of the current situation in the computational fluid dynamics (CFD) modeling of fuel cells and highlights the significant challenges that lie ahead in the development of a comprehensive CFD model for fuel cell applications. The paper focuses on the issues concerned with solid oxide fuel cells and proton exchange membrane fuel cells because these are the two most poplar and probably the most promising types of fuel cells for both stationary and transport applications. However, the general principles presented in this paper are applicable to all types of fuel cells.

Computational Fluid Dynamics Modeling of Impinging Gas-Jet Systems: I. Assessment of Eddy Viscosity Models

2005 ◽  
Vol 127 (4) ◽  
pp. 691-703 ◽  
Author(s):  
M. Coussirat ◽  
J. van Beeck ◽  
M. Mestres ◽  
E. Egusguiza ◽  
J.-M. Buchlin ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nusselt Number ◽  
Eddy Viscosity ◽  
Gas Jet ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Mean Values ◽  
Viscosity Models ◽  
Good Agreement

Computational fluid dynamics plays an important role in engineering design. To gain insight into solving problems involving complex industrial flows, such as impinging gas-jet systems (IJS), an evaluation of several eddy viscosity models, applied to these IJS has been made. Good agreement with experimental mean values for the field velocities and Nusselt number was obtained, but velocity fluctuations and local values of Nusselt number along the wall disagree with the experiments in some cases. Experiments show a clear relation between the nozzle-to-plate distance and the Nusselt number at the stagnation point. Those trends were only reproduced by some of the numerical experiments. The conclusions of this study are useful in the field of heat transfer predictions in industrial IJS devices, and therefore for its design.

scholarly journals A STUDY OF COMPARTMENT FIRE UNDER FORCED VENTILATION: EXPERIMENTAL AND COMPUTATIONAL FLUID DYNAMICS MODELING

2010 ◽  
Vol 7 (2) ◽  
pp. 29-41
Author(s):  
M.Z. Abu Bakar ◽  
Y. Wu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flame Height ◽  
Compartment Fire ◽  
Forced Ventilation ◽  
Dynamics Modeling ◽  
Road Tunnel ◽  
Computational Fluid Dynamics Modeling ◽  
Computational Fluid Dynamics Cfd ◽  
Flame Shape

This paper discusses on the dynamic behavior of the flame and smoke inside a compartment fire. The compartment can be referred to a room, road tunnel, duct, compartment or a building. A series of small scales experiments were carried on four rectangular ducts that have the same height (250 mm) but different widths (125 mm, 250 mm, 500 mm and 1000 mm). Fire simulations on the same compartments were performed to investigate the effectiveness of Computational Fluid Dynamics (CFD) in predicting fire phenomenon. CFD was found capable to predict fire phenomenon such as flame shape, flame height and flame tilt angle similar to the experiment.

scholarly journals Computational Fluid Dynamics Modeling of Liver Radioembolization: A Review

2021 ◽  
Author(s):  
Jorge Aramburu ◽  
Raúl Antón ◽  
Macarena Rodríguez-Fraile ◽  
Bruno Sangro ◽  
José Ignacio Bilbao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Point Of View ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Modeling ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Intraarterial Therapy

AbstractYttrium-90 radioembolization (RE) is a widely used transcatheter intraarterial therapy for patients with unresectable liver cancer. In the last decade, computer simulations of hepatic artery hemodynamics during RE have been performed with the aim of better understanding and improving the therapy. In this review, we introduce the concept of computational fluid dynamics (CFD) modeling with a clinical perspective and we review the CFD models used to study RE from the fluid mechanics point of view. Finally, we show what CFD simulations have taught us about the hemodynamics during RE, the current capabilities of CFD simulations of RE, and we suggest some future perspectives.

scholarly journals 3D computational fluid dynamics modeling of temperature and humidity in a humidified greenhouse

2021 ◽  
Vol 13 (1) ◽  
pp. 17-31
Author(s):  
Cuauhtémoc Pérez-Vega ◽  
◽  
José Armando Ramírez-Arias ◽  
Irineo L. López-Cruz ◽  
Ramón Arteaga-Ramírez ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Ventilation ◽  
Temporal Distribution ◽  
Cfd Modeling ◽  
Cfd Model ◽  
Dynamics Modeling ◽  
Temperature And Humidity ◽  
Humidity Measurements ◽  
Computational Fluid Dynamics Cfd

Introduction: Medium and low technology greenhouses use natural ventilation as a method of temperature and humidity control. However, at certain times of the year, this is insufficient to extract excess heat inside the greenhouse, so devices such as hydrophanes (humidifiers) have been implemented to reduce the temperature. It is necessary to know the behavior of temperature and humidity, since both factors influence the development of crops and, therefore, their yield. Objective: To develop a computational fluid dynamics (CFD) model of a naturally ventilated zenithal greenhouse equipped with hydrophanes to understand the spatial and temporal distribution of temperature and humidity inside the greenhouse. Methodology: The experiment was carried out in a greenhouse equipped with hydrophanes and grown with bell pepper. Temperature and humidity measurements were performed from March 7 to 25, 2014. The ANSYS Workbench program was used for the 3D CFD modeling. Results: The CFD model satisfactorily described the temperature and humidity distribution of the greenhouse, with an error of 0.11 to 3.43 °C for temperature, and 0.44 to 10.80 % for humidity. Limitations of the study: Numerical modeling using CFD is inadequate to model the temporality of the variables. Originality: There are few studies that model humidity behavior with CFD and the use of hydrophanes in Mexico. Conclusions: The CFD model allowed visualizing the distribution of temperature and air humidity inside the greenhouse.

Mixing in Large Scale Tanks: Part II — Full Scale Pump Testing

2004 ◽  
Author(s):  
David B. Stefanko ◽  
Robert A. Dimenna ◽  
Richard A. Leishear ◽  
Si Y. Lee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nuclear Waste ◽  
Large Scale ◽  
Test Facility ◽  
Cfd Model ◽  
Velocity Mapping ◽  
Computational Fluid Dynamics Cfd ◽  
Pump Testing ◽  
Good Agreement

Velocities in the discharge jet of a submerged Advanced Design Mixer Pump (ADMP) were measured in an eighty-five foot diameter tank, and were successfully compared to predictions from a computational fluid dynamics (CFD) model. The ADMP is a 10400 gallon per minute, dual nozzle pump ultimately used to mix the contents of a nuclear waste tank prior to further processing. The pump was initially installed, operated, and tested in a full-diameter test facility tank containing seventy inches of water. The horizontal discharge jets of the pump established a steady flow pattern in the tank, and the resulting velocities were measured throughout the tank. The data from these measurements were statistically averaged to obtain local velocities at each of the measured points in the tank. This experimental velocity mapping was compared to the results of a CFD model and showed good agreement with the calculated velocities.

Computational Fluid Dynamics Modeling of Palm Fruit Pyrolysis in a Fast Fluidized Bed Reactor

2013 ◽  
Vol 699 ◽  
pp. 822-828
Author(s):  
P.L. Mtui
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluidized Bed ◽  
Volume Fraction ◽  
Pyrolysis Oil ◽  
Dynamics Modeling ◽  
Palm Fruit ◽  
Computational Fluid Dynamics Modeling ◽  
Computational Fluid Dynamics Cfd ◽  
Biomass Particles

The palm fruit biomass is introduced into the pyrolysis reactor bed and the transport equations for heat, mass and momentum transfer are solved using computational fluid dynamics (CFD) technique. The Eulerian-Eulerian approach is employed to model fluidizing behavior of the sand for an externally heated reactor prior to the introduction of the biomass. The particle motion in the reactor is computed using the drag laws which depend on the local volume fraction of each phase. Heat transfer from the fluidized bed to the biomass particles together with the pyrolysis reactions were simulated by Fluent CFD code through user-defined function (UDF). Spontaneous production of pyrolysis oil, char and non-condensable gases (NCG) confirm the observation widely reported in literature. The computer model can potentially be used to assess other candidate biomass sources also to assist design of optimized pyrolysis reactors.

scholarly journals Morphological and Hemodynamic Changes during Cerebral Aneurysm Growth

2021 ◽  
Vol 11 (4) ◽  
pp. 520
Author(s):  
Emily R. Nordahl ◽  
Susheil Uthamaraj ◽  
Kendall D. Dennis ◽  
Alena Sejkorová ◽  
Aleš Hejčl ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Swirling Flow ◽  
Morphological Changes ◽  
Cerebral Aneurysms ◽  
Patient Specific ◽  
Aneurysm Wall ◽  
Aneurysm Growth ◽  
Computational Fluid Dynamics Cfd

Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic properties related to the rupture of cerebral aneurysms. Few of these studies deal specifically with aneurysm growth and most only use a single time instance within the aneurysm growth history. The present retrospective study investigated four patient-specific aneurysms, once at initial diagnosis and then at follow-up, to analyze hemodynamic and morphological changes. Aneurysm geometries were segmented via the medical image processing software Mimics. The geometries were meshed and a computational fluid dynamics (CFD) analysis was performed using ANSYS. Results showed that major geometry bulk growth occurred in areas of low wall shear stress (WSS). Wall shape remodeling near neck impingement regions occurred in areas with large gradients of WSS and oscillatory shear index. This study found that growth occurred in areas where low WSS was accompanied by high velocity gradients between the aneurysm wall and large swirling flow structures. A new finding was that all cases showed an increase in kinetic energy from the first time point to the second, and this change in kinetic energy seems correlated to the change in aneurysm volume.

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