Some observations on the initiation and onset of detonation

2012 ◽  
Vol 370 (1960) ◽  
pp. 715-739 ◽  
Author(s):  
Geraint Thomas
Keyword(s):  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Experimental Studies ◽  
Practical Applications ◽  
Deflagration To Detonation Transition ◽  
Dynamic Methods ◽  
Detonation Transition ◽  
Transition To Detonation

The results of experimental studies during which transition to detonation events occurred are presented. These observations and their interpretation are then discussed, and the conditions for the onset of detonation are described, with particular attention paid to the nature of the phenomena of deflagration-to-detonation transition. The resulting implications for predicting detonation evolution using computational fluid dynamic methods in practical applications are also discussed.

Evaluation of computational fluid dynamic methods for reactor safety analysis (ECORA)

2005 ◽  
Vol 235 (2-4) ◽  
pp. 359-368 ◽  
Author(s):  
M. Scheuerer ◽  
M. Heitsch ◽  
F. Menter ◽  
Y. Egorov ◽  
I. Toth ◽  
...  
Keyword(s):  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Safety Analysis ◽  
Reactor Safety ◽  
Dynamic Methods

scholarly journals Liver Bioreactor Design Issues of Fluid Flow and Zonation, Fibrosis, and Mechanics: A Computational Perspective

2020 ◽  
Vol 11 (1) ◽  
pp. 13
Author(s):  
Vahid Rezania ◽  
Dennis Coombe ◽  
Jack Tuszynski
Keyword(s):  
Tissue Engineering ◽  
Fluid Flow ◽  
Reactive Transport ◽  
Drug Transport ◽  
Fluid Transport ◽  
Fluid Dynamic ◽  
Practical Applications ◽  
Dynamic Methods ◽  
Basic Biology ◽  
And Mathematics

Tissue engineering, with the goal of repairing or replacing damaged tissue and organs, has continued to make dramatic science-based advances since its origins in the late 1980’s and early 1990’s. Such advances are always multi-disciplinary in nature, from basic biology and chemistry through physics and mathematics to various engineering and computer fields. This review will focus its attention on two topics critical for tissue engineering liver development: (a) fluid flow, zonation, and drug screening, and (b) biomechanics, tissue stiffness, and fibrosis, all within the context of 3D structures. First, a general overview of various bioreactor designs developed to investigate fluid transport and tissue biomechanics is given. This includes a mention of computational fluid dynamic methods used to optimize and validate these designs. Thereafter, the perspective provided by computer simulations of flow, reactive transport, and biomechanics responses at the scale of the liver lobule and liver tissue is outlined, in addition to how bioreactor-measured properties can be utilized in these models. Here, the fundamental issues of tortuosity and upscaling are highlighted, as well as the role of disease and fibrosis in these issues. Some idealized simulations of the effects of fibrosis on lobule drug transport and mechanics responses are provided to further illustrate these concepts. This review concludes with an outline of some practical applications of tissue engineering advances and how efficient computational upscaling techniques, such as dual continuum modeling, might be used to quantify the transition of bioreactor results to the full liver scale.

Computational Fluid Dynamic Analysis of an Instrumented Endotracheal Tube for Total Liquid Ventilation to Optimize Pressure Transducer Positioning

2009 ◽  
Author(s):  
Adriano Zaffora ◽  
Paola Bagnoli ◽  
Roberto Fumero ◽  
Maria Laura Costantino
Keyword(s):  
Fluid Dynamics ◽  
Endotracheal Tube ◽  
Computational Fluid Dynamic ◽  
Airway Pressure ◽  
Pressure Transducer ◽  
Fluid Dynamic ◽  
Experimental Studies ◽  
Conventional Mechanical Ventilation ◽  
Liquid Ventilation ◽  
Computational Fluid Dynamic Analysis

Despite advances in respiratory care, the treatment of critical neonatal patients with conventional mechanical ventilation (CMV) techniques has still many drawbacks. To address this issue, Total Liquid Ventilation (TLV) with liquid perfluorocarbons (PFC) has been investigated as an alternative respiratory modality [1,2]. A dedicated TLV ventilator supplies PFC tidal volumes (TV) through an endotracheal tube (ETT) inserted into the trachea. In experimental studies, TLV proved to be able to support pulmonary gas exchange while preserving lung structure and function. Moreover, PFC properties make these liquids an optimal medium to treat neonatal respiratory failure [1–3]. However, different aspects of TLV have to be further investigated for a safe transition from the laboratory experience to the clinical application. One of these aspects is the possible airway and lung injury that may be caused by the peculiar fluid dynamics developed when using an incompressible and viscous liquid instead of air as a respiratory medium. To overcome this issue, continuous reliable real-time monitoring of airway pressure during TLV is crucial. Thus, the instrumentation of the ETT with a pressure transducer (PT) is mandatory to perform a safe TLV treatment [4–6]. At present, no commercial instrumented ETTs designed for TLV are available; thus during TLV experimental animal trials [4–6] ETT prototypes instrumented with homemade PT-equipped catheters are currently used. However, the positioning of this catheter has to be optimized in order to reduce fluid dynamic disturbances that can alter pressure measurements. Aim of this study is to investigate on the PFC fluid-dynamic patterns in the presence of the catheter by computational fluid dynamic (CFD) analysis, in the view of the development of a TLV dedicated instrumented ETT. In particular, the effect of two different positioning of the PT catheter on the PFC fluid dynamics and airway pressure measurement was evaluated for a neonatal ETT.

scholarly journals Computational fluid dynamic models as tools to predict aerosol distribution in tracheobronchial airways

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Claudia Atzeni ◽  
Gianluca Lesma ◽  
Gabriele Dubini ◽  
Maurizio Masi ◽  
Filippo Rossi ◽  
...  
Keyword(s):  
Computational Fluid Dynamic ◽  
Dynamic Models ◽  
Elderly Women ◽  
Dynamic Condition ◽  
Fluid Dynamic ◽  
Experimental Studies ◽  
Aerosol Deposition ◽  
Geometrical Model ◽  
Sixth Generation ◽  
Breath Cycle

AbstractAerosol and pollutants, in form of particulates 5–8 μm in main size face every day our respiratory system as natural suspension in air or forced to be inhaled as a coadjutant in a medical therapy for respiratory diseases. This inhalation happens in children to elderly, women and men, healthy or sick and disable people. In this paper we analyzed the inhalation of aerosol in conditions assimilable to the thermal therapy. We use a computational fluid dynamic 3D model to compute and visualize the trajectories of aerosol (3–7–10–25 µm) down to the sixth generation of bronchi, in a steady and dynamic condition (7 µm) set as breath cycle at rest. Results, compared to a set of milestone experimental studies published in literature, allow the comprehension of particles behavior during the inhalation from mouth to bronchi sixth generation, the visualization of jet at larynx constriction and vortices, in an averaged characteristic rigorous geometrical model including tracheal rings. Results on trajectories and deposition show the importance of the including transient physiological breath cycle on aerosol deposition analyses. Numerical and graphical results, may enable the design of medical devices and protocols to make the inhalations more effective in all the users’ population.

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