Fluid Flow Resistance Through Hemispherical Dimpled Plates in Parallel and Zigzag Configurations

2018 ◽  
Vol 12 (11) ◽  
pp. 885
Author(s):  
Nasaruddin Salam ◽  
Rustan Tarakka ◽  
Jalaluddin Jalaluddin ◽  
Muh. Setiawan Sukardin
Keyword(s):  
2001 ◽  
Author(s):  
J. H. Du ◽  
B. Ma ◽  
W. Wu ◽  
X. J. Hu ◽  
B. X. Wang

Abstract Experiments on fluid flow and heat transfer in a glass bead packed channel between two parallel grooved plates were conducted. The effects of the grooves on the surface of the heated plate upon the flow resistance and heat transfer were investigated. The results indicated that the grooves on the plate surface change the contact condition of the packed beads to the wall and increase the wall effect of the packed channels. Its direct consequence is to lower the flow resistance. The film heat transfer coefficient on the wall may be increased or rebated. It is demonstrated that a proper combination of packed beads and grooves can lead to the optimum performance of heat transfer for a specific configuration.


2013 ◽  
Vol 334-335 ◽  
pp. 322-328 ◽  
Author(s):  
Ana Serrenho ◽  
Antonio F. Miguel

The present study focuses on fluid flow and particle transport in symmetric T-shaped structures formed by tubes with circular and square cross-section. The performances of optimized structures (i.e., structures designed based on constructal allometric laws for minimum flow resistance) and not optimized structures were studied. Flow resistance and particle penetration efficiency were studied both for laminar and turbulent flow regimes, and for micrometer and submicrometer particles. Optimized structures have been proven to perform better for fluid flow but they have a similar performance for particle transport.


2021 ◽  
Vol 39 (3) ◽  
pp. 817-824
Author(s):  
Ameer Abed Jaddoa

This paper analyzes the effect of fluid flow characteristics on the convection heat transfer for mini-helically coiled tubes (HCT) using supercritical carbon dioxide (CO2) as a natural refrigerant. Two experimental cases have studied in this work for mini-helically coiled tubes at different diameters with different coil pitches for analyzing the convection heat transfer with flow resistance. In the first case, the inner tube diameter, coil diameter and coil pitch were 5 mm, 200 mm and 10 mm respectively, while 10 mm, 100 mm and 5 mm were for the second case. Moreover, this work has also investigated the influence of frictional pressure drop, heat flux, friction factor and mass flux on dimensionless exergy destruction. The work environments were 300-500 K as an inlet temperatures range, 200-2000 Kg / (m2. s) as a mass heat fluxes range, 50,000-500,000 as a Reynolds number (Re) range and 50-200 Kw/m2 as an inner heat fluxes range. As a result, a large effect has been observed for dimensionless exergy destruction compared with the flow friction of CO2 which induced by heat transfer irreversibility. On the other point of view, a good sensitivity of optimal Re with the tube dimeter and mass flux also noticed compared with the heat flux. At a suitable range for Re, smallest and best exergy destruction also noticed for the tube diameters. A correlation has for the optimal Reynolds number as function of main dimensionless parameters related to wall heat flux, mass flux, fluid properties and geometric dimensions is proposed. Characteristics of the fluid flow had influenced significantly by mass and heat fluxes. In the future, the collected experimental data can be employed in order to design and improve the refrigeration conditioning performance for exchangers and other systems such as heat pumps.


Author(s):  
C. C.-C. Choi ◽  
S. H.-K. Lee

Motivated by its frequent appearance in practical applications, scientists and engineers have been putting much efforts to pursue the ability to predict fluid flow behavior in sphere packed bed, in particular the fluid-solid interaction therein. The network model has recently been used to predict the fluid flow behavior in a sphere packed bed for a smaller length-scale domain of interest. The major questions for this approach are the representation of the irregular void space as a three dimensional network and the assignment of the flow resistance values. The application of Deluanay Cell to discretize the void space helps retain the geometrical and topological information without any empirical data fitting in. However, the calculation of the flow resistance within the Delaunay cell is still a question to be solved due to its highly irregular topology. The objective of this study is to solve for the flow resistance between the pores in a simple cubic retaining all the geometrical information. And then to correlate the flow resistance with different values of Reynolds number such that the application of network model could extend outside the creeping flow regime. The results has been validated against experimental correlation and then correlated with Reynolds number with a correlation factor larger than 0.9.


1999 ◽  
Vol 277 (2) ◽  
pp. C330-C342 ◽  
Author(s):  
Johnnie L. Underwood ◽  
Collin G. Murphy ◽  
Janet Chen ◽  
Linda Franse-Carman ◽  
Irmgard Wood ◽  
...  

The regulation of transendothelial fluid flow by glucocorticoids was studied in vitro with use of human endothelial cells cultured from Schlemm’s canal (SCE) and the trabecular meshwork (TM) in conjunction with computer-linked flowmeters. After 2–7 wk of 500 nM dexamethasone (Dex) treatment, the following physiological, morphometric, and biochemical alterations were observed: a 3- to 5-fold increase in fluid flow resistance, a 2-fold increase in the representation of tight junctions, a 10- to 30-fold reduction in the mean area occupied by interendothelial “gaps” or preferential flow channels, and a 3- to 5-fold increase in the expression of the junction-associated protein ZO-1. The more resistive SCE cells expressed two isoforms of ZO-1; TM cells expressed only one. To investigate the role of ZO-1 in the aforementioned Dex effects, its expression was inhibited using antisense phosphorothioate oligonucleotides, and the response was compared with that observed with the use of sense and nonsense phosphorothioate oligonucleotides. Inhibition of ZO-1 expression abolished the Dex-induced increase in resistance and the accompanying alterations in cell junctions and gaps. These results support the hypothesis that intercellular junctions are necessary for the development and maintenance of transendothelial flow resistance in cultured SCE and TM cells and are likely involved in the mechanism of increased resistance associated with glucocorticoid exposure.


Author(s):  
Kinichi TORIKAI ◽  
Masao HORI ◽  
Toshi YAMASAKI

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