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Apparent Porous Media Gas Dispersion in Response to Rapid Pressure Fluctuations

Poulsen, Tjalfe G.1; Sharma, Prabhakar2

doi: 10.1097/SS.0b013e3182372fae
Technical Article

The impact of rapid pressure fluctuations (frequency >0.02 min−1) on gas transport in two filter sands with different gas permeability (k g) was investigated. Pressure fluctuation–induced gas transport characterized as a dispersion process governed by a pressure fluctuation–induced dispersion coefficient (D p) was measured using a column containing the sand, connected to a membrane pump for generating pressure fluctuations. Measurements of D p in both sands were carried out for different combinations of pressure-fluctuation amplitude (A) and frequency (f). To assess if D p is affected by the presence of a background steady gas flux in addition to the gas movement induced by the pressure fluctuations, D p measurements were carried out for different constant pore gas velocities (u). Measurements of D p corresponding to a total of 102 combinations of u, A, f, and k g were carried out. The results showed that the value of D p increases with increasing A, f, and k g but is independent of u. Relations between D p and A, f, and k g were generally strong.

1Environmental Engineering Section, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark. Dr. Tjalfe G. Poulsen is corresponding author. E-mail: tgp@bio.aau.dk

2Department of Earth Sciences, Uppsala University, Villavägen 16 SE-752 36, Uppsala, Sweden.

Received June 22, 2011.

Accepted for publication September 12, 2011.

Financial Disclosures/Conflicts of Interest: Funding was provided in part by the Villum Foundation, Søborg, Denmark. The authors have no conflicts of interest to report.

© 2011 Lippincott Williams & Wilkins, Inc.