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Title: Measurements of pore-scale flow through apertures

Abstract

Pore-scale aperture effects on flow in pore networks was studied in the laboratory to provide a parameterization for use in transport models. Four cases were considered: regular and irregular pillar/pore alignment with and without an aperture. The velocity field of each case was measured and simulated, providing quantitatively comparable results. Two aperture effect parameterizations were considered: permeability and transmission. Permeability values varied by an order of magnitude between the cases with and without apertures. However, transmission did not correlate with permeability. Despite having much greater permeability the regular aperture case permitted less transmission than the regular case. Moreover, both irregular cases had greater transmission than the regular cases, a difference not supported by the permeabilities. Overall, these findings suggest that pore-scale aperture effects on flow though a pore-network may not be adequately captured by properties such as permeability for applications that are interested in determining particle transport volume and timing.

Authors:
 [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1395436
Report Number(s):
SAND2017-10219
657181
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES

Citation Formats

Chojnicki, Kirsten. Measurements of pore-scale flow through apertures. United States: N. p., 2017. Web. doi:10.2172/1395436.
Chojnicki, Kirsten. Measurements of pore-scale flow through apertures. United States. doi:10.2172/1395436.
Chojnicki, Kirsten. Fri . "Measurements of pore-scale flow through apertures". United States. doi:10.2172/1395436. https://www.osti.gov/servlets/purl/1395436.
@article{osti_1395436,
title = {Measurements of pore-scale flow through apertures},
author = {Chojnicki, Kirsten},
abstractNote = {Pore-scale aperture effects on flow in pore networks was studied in the laboratory to provide a parameterization for use in transport models. Four cases were considered: regular and irregular pillar/pore alignment with and without an aperture. The velocity field of each case was measured and simulated, providing quantitatively comparable results. Two aperture effect parameterizations were considered: permeability and transmission. Permeability values varied by an order of magnitude between the cases with and without apertures. However, transmission did not correlate with permeability. Despite having much greater permeability the regular aperture case permitted less transmission than the regular case. Moreover, both irregular cases had greater transmission than the regular cases, a difference not supported by the permeabilities. Overall, these findings suggest that pore-scale aperture effects on flow though a pore-network may not be adequately captured by properties such as permeability for applications that are interested in determining particle transport volume and timing.},
doi = {10.2172/1395436},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Sep 01 00:00:00 EDT 2017},
month = {Fri Sep 01 00:00:00 EDT 2017}
}

Technical Report:

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  • An aperture with a 1/2-in. dia opening, tapered at 60 deg to a 11/2-in. dia opening, and 1/32 in. long is analyzed. The measurements include mass flow rates, pressure profiles in the aperture, and thrust measurements as functions of the initial pressure of saturated water in the vessel. The pressure remains constant along the length of the aperture and a critical pressure ratio of 0.3 is observed, independent of the upstream saturation pressure. Use of this ratio to evaluate the backpressure for the usual orifice equation leads to an accurate prediction of the mass flow rates. Thrust measurements are comparedmore » with predictions. Several models are used to estimate the quality. As yet, no model is successful in predicting in the back pressures in the aperture. (auth)« less
  • Equations of motion are developed for the case of a fluid flowing across an aperture. The flow of saturated fluid within the pressure vessel is assumed to be the same as that of a single-phase incompressible fluid, although after it leaves the aperture, its flow characteristics are changed. The calculated and experimental thrusts for saturated water are found to agree, confirming the assumption of no flashing near the aperture within the pressure vessel. (D.L.C.)
  • An experimental study on the discharge rates of saturated and subcooled Freon-11 through apertures and short tubes is reported. The experiment covered a range of modified cavitation numbers between 0 and 500, length-to-diameter ratios of small-diameter tubes between 2 and 55, and sharp-edge apertures of nine different geometric configurations. It was found that below the modified cavitation number of 10, the iluid exhibits completely metastable singlephase ilow. When the modified cavitation number exceeds 14, two-phase critical flow may exist. In the range of modified cavitation numbers between 10 and 14, unstable transitional flow occurs (alternating single- and twophase flow). Eulermore » numbers for the apertures of various configurations, including square, rectangular, and eyeshaped, were found to be in the same order of magnitude as those for circular shapes. The trianguiar orifices were found to possess higher Euler numbers and the Wshaped orifices lower than the circular ones. (auth)« less