Anomaly of excess pressure drops of the flow through very small orifices

1997 ◽  
Vol 9 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Tomiichi Hasegawa ◽  
Masaki Suganuma ◽  
Hiroshi Watanabe
Keyword(s):  
Excess Pressure ◽  
Pressure Drops ◽  
Flow Through

Impact of Print Parameters on Pressure Drop in Turbulent Flow Through 3-D Printed Pipes

2020 ◽  
Author(s):  
Thomas G. Shepard ◽  
John Wentz ◽  
Tucker Bender ◽  
Derek Olmschenk ◽  
Alex Gutenberg
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Acrylonitrile Butadiene Styrene ◽  
Industrial Applications ◽  
Relative Pressure ◽  
Fused Filament Fabrication ◽  
Pressure Drops ◽  
Flow Through

Abstract Flow conduits made via additive manufacturing, commonly referred to as 3-D printing, are of increasing interest for a variety of industrial applications due to the ability to create unique and conformal flow paths that would not be possible with other fabrication techniques. Fused filament fabrication (FFF) is an additive manufacturing technique that is seeing new interest in the creation of internal flow channels with its ability to print high-temperature polymers and soluble supports. Printing parameter choices in the FFF printing process result in surfaces that can have significant profile differences that may significantly impact the flow characteristics within the conduits. In this study, two print parameters were experimentally studied for turbulent water flow through circular pipes created by fused filament fabrication out of acrylonitrile butadiene styrene (ABS). The print layer orientation relative to the flow was investigated for printing layers parallel, perpendicular, and at 45 degrees from the flow axis. Layer thickness were varied from 0.254 mm to 0.330 mm and all channels were created using soluble support structures. Pressure drops were measured for fully developed flow through pipes with an inside diameter of 5 mm and Reynolds numbers up to 62,000. Results are presented in terms of relative pressure drops as well as the wall surface roughness that would lead to such impacts. These flow-determined grain surface roughnesses are then compared against measurements of print surface roughness.

Creeping Flow Through an Axisymmetric Sudden Contraction or Expansion

2001 ◽  
Vol 124 (1) ◽  
pp. 273-278 ◽  
Author(s):  
Sourith Sisavath ◽  
Xudong Jing ◽  
Chris C. Pain ◽  
Robert W. Zimmerman
Keyword(s):  
Pressure Drop ◽  
Expansion Ratio ◽  
Excess Pressure ◽  
Creeping Flow ◽  
Numerical Studies ◽  
Equivalent Length ◽  
Sudden Contraction ◽  
Circular Orifice ◽  
Flow Through ◽  
Infinite Wall

Creeping flow through a sudden contraction/expansion in an axisymmetric pipe is studied. Sampson’s solution for flow through a circular orifice in an infinite wall is used to derive an approximation for the excess pressure drop due to a sudden contraction/expansion in a pipe with a finite expansion ratio. The accuracy of this approximation obtained is verified by comparing its results to finite-element simulations and other previous numerical studies. The result can also be extended to a thin annular obstacle in a circular pipe. The “equivalent length” corresponding to the excess pressure drop is found to be barely half the radius of the smaller tube.

Excess Pressure Drops in Entrance Flows

1982 ◽  
Vol 26 (4) ◽  
pp. 347-357 ◽  
Author(s):  
J. S. Vrentas ◽  
J. L. Duda ◽  
Seong‐Ahn Hong
Keyword(s):  
Excess Pressure ◽  
Pressure Drops

Predicting the excess pressure drop incurred by LPTT fluids in flow through a planar constricted channel

2019 ◽  
Vol 31 (3) ◽  
pp. 149-166
Author(s):  
Taha Rezaee ◽  
Mostafa Esmaeili ◽  
Solmaz Bazargan ◽  
Kayvan Sadeghy
Keyword(s):  
Pressure Drop ◽  
Excess Pressure ◽  
Flow Through ◽  
Constricted Channel

Pressure Drops of Water Flow Through Micromachined Particle Filters

2002 ◽  
Vol 124 (4) ◽  
pp. 1053-1056 ◽  
Author(s):  
Tzung K. Hsiai ◽  
Sung Kwon Cho and ◽  
Joon Mo Yang ◽  
Xing Yang and ◽  
Yu-Chong Tai ◽  
...  
Keyword(s):  
Water Flow ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Side Wall ◽  
Micro Electro Mechanical System ◽  
Numerical Code ◽  
Power Requirement ◽  
Pressure Drops ◽  
Flow Through ◽  
Wall Profile

When the particle is in the order of microns, flow through the small opening produces a large velocity gradient, leading to high viscous dissipation. Understanding the flow field is critical in determining the power requirement. In this paper, we studied water flow through filters fabricated by micro-electro-mechanical system (MEMS) techniques. The pressure drop calculated by a three-dimensional numerical code of the Navier-Stokes equations is in a resonable agreement with the experimental data if the diameter and the side wall profile of the holes are measured with high accuracy.

CFD SIMULATION OF FLOW THROUGH AN OPEN CELL FOAM

2008 ◽  
Vol 19 (05) ◽  
pp. 703-715 ◽  
Author(s):  
G. TABOR ◽  
O. YEO ◽  
P. YOUNG ◽  
P. LAITY
Keyword(s):  
Computational Analysis ◽  
Cfd Simulation ◽  
Flow Speed ◽  
Flow Properties ◽  
Pressure Drops ◽  
Open Cell Foam ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
First Time ◽  
Unit Pressure

A sample of an open-celled plastic foam has been examined using a combination of experimental, microscopic and computational methods. The aim was to use image-based meshing techniques to generate for the first time geometrically faithful models of the microstructure of the foam, and to use Computational Fluid Dynamics (CFD) to compute flow properties and pressure drops across the sample. The microstructure of the foam was also investigated experimentally and using SEM to provide further information for the computational analysis. A comparison was made with existing experimental data on flows through foams, and the unit pressure drop was found to correlate with the flow speed in the appropriate manner.

Anomalous Reduction in Pressure Drops of the Water Flow through Micro-Orifices in High Velocity Ranges

2008 ◽  
Author(s):  
Tomiichi Hasegawa ◽  
Akiomi Ushida ◽  
Takatsune Narumi ◽  
Albert Co ◽  
Gary L. Leal ◽  
...  
Keyword(s):  
Water Flow ◽  
High Velocity ◽  
Pressure Drops ◽  
Flow Through

A Series Pressure Drop Representation for Flow Through Orifice Tubes

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
T. A. Jankowski ◽  
E. N. Schmierer ◽  
F. C. Prenger ◽  
S. P. Ashworth
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Simple Model ◽  
Pressure Drop ◽  
Diameter Ratio ◽  
Pressure Drops ◽  
In Series ◽  
Orifice Flow ◽  
Flow Through ◽  
Length To Diameter Ratio

A simple model is developed here to predict the pressure drop and discharge coefficient for incompressible flow through orifices with length-to-diameter ratio greater than zero (orifice tubes) over wide ranges of Reynolds number. The pressure drop for flow through orifice tubes is represented as two pressure drops in series; namely, a pressure drop for flow through a sharp-edged orifice in series with a pressure drop for developing flow in a straight length of tube. Both of these pressure drop terms are represented in the model using generally accepted correlations and experimental data for developing flows and sharp-edged orifice flow. We show agreement between this simple model and our numerical analysis of laminar orifice flow with length-to-diameter ratio up to 15 and for Reynolds number up to 150. Agreement is also shown between the series pressure drop representation and experimental data over wider ranges of Reynolds number. Not only is the present work useful as a design correlation for equipment relying on flow through orifice tubes but it helps to explain some of the difficulties that previous authors have encountered when comparing experimental observation and available theories.

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