Light transmission measurement of solute dispersion in non-Brownian suspension flow

ALEJANDRO BOSCHAN; MARIANA POBLETE; YANINA L. ROHT; IRENE IPPOLITO; RICARDO CHERTCOFF

EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2014 p. 11101 - 11111

1286-0042

We characterize and employ a light transmission technique to measure the dispersivity of a solute in the flow of a neutrally-buoyant non-Brownian spherical particle suspension in a Hele-Shaw cell (parallelplate axial flow). Particle radii (a) were 20 and 40 μm, the particle bulk volume fraction ϕbulk was 0.2, and the cell aperture was 420 ± 10 μm. In each displacement experiment a suspension with a colouring solute displaces a transparent one at constant flow rates ranging from 0.721 to 0.928 mL/min (corresponding to solute Péclet numbers (Pes) between 350 and 450). A reference measurement, identical to the displacement ones but without particles in the flow (ϕbulk = 0), were performed in the same experimental assembly for comparison purposes. A light calibration related the transmitted intensity I to the solute concentration c for each combination of ϕbulk and a. The time variation of the solute concentration was found to be well-fitted by the solution of the advection-dispersion equation (ADE) in the range of Pes studied, and consequently a dispersion coefficient D and a dispersivity ld of the solute were measured.