Particle release and transport from human skin and clothing: A CFD modeling methodology

Indoor Air ◽  
2021 ◽  
Author(s):  
Douaa Al Assaad ◽  
Shen Yang ◽  
Dusan Licina
Keyword(s):  
Human Skin ◽  
Cfd Modeling ◽  
Particle Release ◽  
Modeling Methodology

CFD Modeling of Fuel Rod Heat Transfer to Aid in the Risk Assessment of Fuel Rod Failure Due to Localized Crud

2009 ◽  
Author(s):  
Steven Beltz ◽  
Bin Liu ◽  
Zeses Karoutas
Keyword(s):  
Heat Transfer ◽  
Risk Assessment ◽  
Heat Transfer Coefficient ◽  
Hot Spots ◽  
Cfd Modeling ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Fuel Rod ◽  
Modeling Methodology ◽  
Fuel Design

This paper presents a computational fluid dynamics (CFD) modeling methodology that has been developed to provide predictions of very local heat transfer variation in fuel rod assemblies. Results from the CFD analysis are used in HIDUTYDRV and other advanced codes that have been developed and are used internally by Westinghouse to predict very local crud deposition and dryout. This methodology is used in making the EPRI Level IV crud and corrosion guideline assessments, which were developed in response to the INPO 0 by 2010 initiatives. This methodology has been in production use for risk assessment of CE-design 14×14 and 16×16 fuel reloads. The methodology is in the process of being extended to other Westinghouse fuel design reloads. Local crud deposition and dryout are strongly dependent on very local boiling or steaming on small areas of the fuel rod, often referred to as local hot spots. These local hot spots can not be predicted utilizing standard subchannel modeling methodology because subchannel models do not provide sufficient azimuthal detail of individual rods. Local hot spots are also very dependent on the particular grid features, which are not explicitly modeled in subchannel analysis. The commercial code Star-CD by CD-ADAPCO is utilized to develop a detailed CFD model of a single fuel assembly grid span. Detailed azimuthal and axial predictions of the heat transfer coefficient are made for each rod in the model. These predictions are then normalized to a Dittus-Boelter based heat transfer coefficient so that the predictions can be translated to other spans and other fuel assemblies. Details of this translation as well as the use of normalized heat transfer coefficients in the advanced codes used to predict local crud and dryout are provided in a separate follow-on paper ICONE17-75715 also being presented at ICONE17. This paper presents details on the CFD methodology that has been developed to predict local normalized heat transfer coefficients for a fuel rod assembly. Results for a particular application are provided to illustrate the methodology. The application is for a fuel design that contains mixing grids and spans with and without intermediate flow mixers.

scholarly journals Study of a Pump as Turbine for a Hydraulic Urban Network Using a Tridimensional CFD Modeling Methodology

2015 ◽  
Vol 82 ◽  
pp. 201-208 ◽  
Author(s):  
Dario Buono ◽  
Emma Frosina ◽  
Antonio Mazzone ◽  
Umberto Cesaro ◽  
Adolfo Senatore
Keyword(s):  
Cfd Modeling ◽  
Urban Network ◽  
Modeling Methodology

scholarly journals Refinement of the characteristics of the aerodynamic resistance to the movement of special wheeled chassis and tractors based on the use of computational gas dynamics methods

2021 ◽  
Vol 7 (3) ◽  
pp. 270-279
Author(s):  
V.I. Tarichko ◽  
◽  
P.I. Shalupina ◽  
Keyword(s):  
Gas Dynamics ◽  
Aerodynamic Drag ◽  
Aerodynamic Resistance ◽  
Cfd Modeling ◽  
Modeling Methodology ◽  
Calculation Results ◽  
Aerodynamic Drag Coefficient ◽  
Wheeled Vehicles ◽  
Selection Of ◽  
Preliminary Selection

An accurate assessment of the characteristics of the aerodynamic resistance to movement is important for the preliminary selection of the parameters of the engine, transmission and chassis of a special wheeled chassis or tractor. The strength of the movement resistance affects the dynamic characteristics of the car. The existing calculation methods allow for a wide variation of the aerodynamic drag coefficient, which complicates the task of preliminary selection of car parameters. The purpose of this article is to clarify and develop the engineering methodology for carrying out traction-dynamic calculations of special wheeled vehicles and tractors based on the results of computer modeling performed using computational fluid and gas dynamics (CFD modeling) methods. The modeling methodology and calculation results of a special wheeled chassis manufactured by JSC «BAZ» are considered.

Two-Phase CFD Study of Coolant through a 5×5 Rod Bundles with Grid Spacers

2013 ◽  
Vol 444-445 ◽  
pp. 529-533
Author(s):  
Shen Gen Tan ◽  
Song Wei Li ◽  
Yong Jun Jiao ◽  
Qing Lu ◽  
Guo Bin Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Two Phase Flow ◽  
Size Group ◽  
Cfd Modeling ◽  
Transfer Model ◽  
Phase Flow ◽  
Rod Bundles ◽  
Two Phase ◽  
Pressurized Water ◽  
Modeling Methodology

A numerical study using computational fluid dynamics (CFD) under air/water two-phase flow condition without thermal transmission is carried out utilizing the commercial CFD code CFX. A detailed geometry of 5×5 rod bundles with two grid spacers in the Pressurized Water Reactor (PWR) is set up for analyzing. The Multiple Size Group (MUSIG) model based on the population balance equation is employed to describe the characteristic of flow field in which the dispersed phase has a large variation in size, and the breakup and coalescence interaction among different sizes of the bubbles. The effects of the size fraction at inlet, the size group quantities, the breakup and coalescence coefficients, the momentum transfer model, and so on, are studied. The results demonstrate that various parameters and two-phase model have different impacts on the analysis results. The detailed CFD modeling methodology for two-phase flow conditions in PWR fuel assemblies is developed according to the above-mentioned investigations. The flow field patterns and air/water phase distributions in the computational results shows that the two-phase modeling methodology in the present work is reasonable.

A web-like network of type vi collagen in human skin is revealed by immuno-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 382-383
Author(s):  
Douglas R. Keene ◽  
Robert W. Glanville ◽  
Eva Engvall
Keyword(s):  
Electron Microscopy ◽  
Monoclonal Antibody ◽  
Human Skin ◽  
Basement Membranes ◽  
Primary Antibody ◽  
Fat Cells ◽  
Secondary Antibody ◽  
Type Vi Collagen ◽  
Dermal Matrix ◽  
Immuno Electron Microscopy

A mouse monoclonal antibody (5C6) prepared against human type VI collagen (1) has been used in this study to immunolocalize type VI collagen in human skin. The enbloc method used involves exposing whole tissue pieces to primary antibody and 5 nm gold conjugated secondary antibody before fixation, and has been described in detail elsewhere (2).Biopsies were taken from individuals ranging in age from neonate to 65 years old. By immuno-electron microscopy, type VI collagen is found to be distributed as a fine branching network closely associated with (but not attached to) banded collagen fibrils containing types I and III collagen (Fig. 1). It appears to enwrap fibers, to weave between individual fibrils within a fiber, and to span the distance separating fibers, creating a “web-like network” which entraps fibers within deep papillary and reticular dermal layers (Fig. 2). Relative to that in the dermal matrix, the concentration of type VI collagen is higher around endothelial basement membranes limiting the outer boundaries of nerves, capillaries, and fat cells (Fig. 3).

Effect of Acetone and Kerosene on Skin Ultrastructure

1972 ◽  
Vol 30 ◽  
pp. 92-93
Author(s):  
A. P. Lupulescu ◽  
H. Pinkus ◽  
D. J. Birmingham
Keyword(s):  
Electron Microscopy ◽  
Human Skin ◽  
Osmium Tetroxide ◽  
Human Epidermis ◽  
Ultrastructural Changes ◽  
Chemical Agents ◽  
Skin Ultrastructure ◽  
Volar Surface

Our laboratory is engaged in the study of the effect of different chemical agents on human skin, using electron microscopy. Previous investigations revealed that topical use of a strong alkali (NaOH 1N) or acid (HCl 1N), induces ultrastructural changes in the upper layers of human epidermis. In the current experiments, acetone and kerosene, which are primarily lipid solvents, were topically used on the volar surface of the forearm of Caucasian and Negro volunteers. Skin specimens were bioptically removed after 90 min. exposure and 72. hours later, fixed in 3% buffered glutaraldehyde, postfixed in 1% phosphate osmium tetroxide, then flat embedded in Epon.

Changes in corneocyte element concentrations occur in skin inner stratum corneum

1990 ◽  
Vol 48 (2) ◽  
pp. 146-147
Author(s):  
R. R. Warner
Keyword(s):  
Stratum Corneum ◽  
Human Skin ◽  
Element Concentration ◽  
Skin Barrier ◽  
Barrier Properties ◽  
Brick Wall ◽  
Inorganic Elements ◽  
Dry Skin ◽  
Skin Biopsies ◽  
Intercellular Lipid

Keratinocytes undergo maturation during their transit through the viable layers of skin, and then abruptly transform into flattened, anuclear corneocytes that constitute the cellular component of the skin barrier, the stratum corneum (SC). The SC is generally considered to be homogeneous in its structure and barrier properties, and is often shown schematically as a featureless brick wall, the “bricks” being the corneocytes, the “mortar” being intercellular lipid. Previously we showed the outer SC was not homogeneous in its composition, but contained steep gradients of the physiological inorganic elements Na, K and Cl, likely originating from sweat salts. Here we show the innermost corneocytes in human skin are also heterogeneous in composition, undergoing systematic changes in intracellular element concentration during transit into the interior of the SC.Human skin biopsies were taken from the lower leg of individuals with both “good” and “dry” skin and plunge-frozen in a stirred, cooled isopentane/propane mixture.

Desmosomal distribution in the epidermis of a non-contracting human skin equivalent

1992 ◽  
Vol 50 (1) ◽  
pp. 896-897
Author(s):  
L.X. Oakford ◽  
S.D. Dimitrijevich ◽  
R. Gracy
Keyword(s):  
Human Skin ◽  
Basal Layer ◽  
Skin Equivalent ◽  
Tissue Component ◽  
Intact Skin ◽  
Similar Sequence ◽  
Sequence Of Events ◽  
Suprabasal Keratinocytes ◽  
Human Skin Equivalent

In intact skin the epidermal layer is a dynamic tissue component which is maintained by a basal layer of mitotically active cells. The protective upper epidermis, the stratum corneum, is generated by differentiation of the suprabasal keratinocytes which eventually desquamate as anuclear comeocytes. A similar sequence of events is observed in vitro in the non-contracting human skin equivalent (HSE) which was developed in this lab (1). As a part of the definition process for this model of living skin we are examining its ultrastructural features. Since desmosomes are important in maintaining cell-cell interactions in stratified epithelia their distribution in HSE was examined.

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