Enhancement of mass transfer from particles by local shear-rate and correlations with application to drug dissolution |
| |
Authors: | Yanxing Wang James G. Brasseur |
| |
Affiliation: | 1. School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, Georgia;2. Smead Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado |
| |
Abstract: | We analyze hydrodynamic enhancement of mass (or heat) release rate from small spherical particles within fluid flows from local flow shear-rate, with application to drug dissolution. Combining asymptotic theories in the high/low shear Peclet number limits in Stokes flow with 205 carefully-developed computational experiments, we develop accurate correlations for shear enhancement of Sherwood/Nusselt number (Sh/Nu) as a function of shear Peclet and Reynolds number (S*, Re S). The data spanned S* from 0 to 500 and Re S from 0 to 10. In Stokes flow our correlations are highly accurate over the entire S* range, whereas for finite Re S < 1 accuracy is good for S* up to a few thousand. Shear enhancement results from highly three-dimensional spiraling flow created by particle spin. We develop a model for particle slip velocity that is inserted into the Ranz/Marshall correlation to show that shear-rate enhancement strongly dominates convection, a result important to drug dissolution. |
| |
Keywords: | convective enhancement dissolution drug dissolution particle heat transfer particle mass transfer shear enhancement |
|
|