CFD Simulation on Valve's Flow Resistance Characteristic

2018 ◽  
Author(s):  
Simin Cao ◽  
Xun He ◽  
Zhu Ye ◽  
Jianyong Lai
Keyword(s):  
Flow Resistance ◽  
Cfd Simulation ◽  
Resistance Characteristic

scholarly journals Experimental Study on Flow Resistance Characteristic of Corrugated Low Finned Tubes

2020 ◽  
Vol 474 ◽  
pp. 052068
Author(s):  
Bin Ren ◽  
Zhe Pu ◽  
Xiaoying Tang ◽  
Hongliang Lu ◽  
Yannan Du ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Resistance ◽  
Resistance Characteristic ◽  
Finned Tubes

Specific Hydraulic Conductivity of Corneal Stroma as Seen by Quick-Freeze/Deep-Etch

2000 ◽  
Vol 123 (2) ◽  
pp. 154-161 ◽  
Author(s):  
Darryl Overby ◽  
Jeffrey Ruberti ◽  
Haiyan Gong ◽  
Thomas F. Freddo ◽  
Mark Johnson
Keyword(s):  
Extracellular Matrix ◽  
Hydraulic Conductivity ◽  
Flow Resistance ◽  
Corneal Stroma ◽  
High Flow ◽  
Depth Of Field ◽  
Resistance Characteristic ◽  
Connective Tissues ◽  
Electron Microscopic ◽  
Microscopic Techniques

Previous studies of the hydraulic conductivity of connective tissues have failed to show a correspondence between ultrastructure and specific hydraulic conductivity. We used the technique of quick-freeze/deep-etch to examine the ultrastructure of the corneal stroma and then utilized morphometric studies to compute the specific hydraulic conductivity of the corneal stroma. Our studies demonstrated ultrastructural elements of the extracellular matrix of the corneal stroma that are not seen using conventional electron microscopic techniques. Furthermore, we found that these structures may be responsible for generating the high flow resistance characteristic of connective tissues. From analysis of micrographs corrected for depth-of-field effects, we used Carmen-Kozeny theory to bound a morphometrically determined specific hydraulic conductivity of the corneal stroma between 0.46×10−14 and 10.3×10−14 cm2. These bounds encompass experimentally measured values in the literature of 0.5×10−14 to 2×10−14 cm2. The largest source of uncertainty was due to the depth-of-field estimates that ranged from 15 to 51 nm; a better estimate would substantially reduce the uncertainty of these morphometrically determined values.

CFD Simulation of Lab Seal Tooth Tip Geometry Variations to Reduce Leakage

2015 ◽  
Author(s):  
Hasham H. Chougule ◽  
Alexander Mirzamoghadam
Keyword(s):  
Flow Field ◽  
Numerical Investigation ◽  
Flow Resistance ◽  
Cfd Simulation ◽  
Labyrinth Seal ◽  
Leakage Flow ◽  
Baseline Model ◽  
Leakage Reduction ◽  
Developing Flow ◽  
Flow Through

A modification of a conventional straight four-tooth labyrinth seal with inclined teeth including single and double stepped notches is proposed. The variants are to be numerically modeled and evaluated for potential leakage reduction through the seal as a result of the developing flow field. The CFD methodology for numerical investigation is first validated by comparison with literature data from static labyrinth seal experiments. The objective is to numerically analyze the proposed “Notched Inclined Teeth” with solid and honeycomb lands and verify the leakages. Another objective is to compare these leakages with the “Stepped Double Notched Straight Tooth” variant discussed by the present authors in a previous paper. Results indicate that the proposed modifications — single and double stepped notched inclined teeth, systematically reduce the seal leakage compared to the baseline straight and forward inclined teeth due to higher turbulence, higher blockages by introducing vortex in leakage flow through step and cavities, and higher flow resistance as compared to baseline model.

A Hybrid Flow Network-CFD Method for Achieving Any Desired Flow Partitioning Through Floor Tiles of a Raised-Floor Data Center

2003 ◽  
Author(s):  
James W. VanGilder ◽  
Ted Lee
Keyword(s):  
Data Center ◽  
Flow Resistance ◽  
Cfd Simulation ◽  
Floor Tile ◽  
Electrical Circuit ◽  
Trial And Error ◽  
Flow Network ◽  
Floor Tiles ◽  
Circuit Analogy ◽  
Cfd Method

A technique is presented which allows a data center designer or operator to achieve any desired partitioning of available airflow among the floor tiles of a raised-floor data center without resorting to trial-and-error. The output from the analysis is a tile-by-tile prescription of flow resistance characteristics (e.g., damper settings), which accomplishes the desired partitioning. The technique is derived from an electrical-circuit analogy of the airflow in the data. Each circuit branch represents one path that air may follow from the CRAC unit supply, through a particular floor tile, and ultimately back to the CRAC return. Any desired flow partitioning through tiles can be achieved by proper adjustment of tile resistances in each circuit; however, by itself, the flow network has too many unknowns to be solvable. A CFD simulation of the entire data center, in which the desired flow partitioning is specified, provides the pressure distribution above (in the room) and below (in the plenum) the floor tiles. The method is illustrated in step-by-step fashion with a simple example case.

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