Influence of Non-Newtonian Rheology on Mass Transfer From a Biofluid in Separated and Reattached Flows

Influence of the rheological model selection on the flow and mass transfer behavior of human blood in a separated and reattached flow region is investigated. Newtonian and non-Newtonian hemorheological models that account for the yield stress and shear-thinning characteristics of blood are used. The conservation of mass, momentum, and species equations as well as the Herschel-Bulkley constitutive equation are solved numerically using a finite-difference scheme. A parametric study is performed to reveal the impact of flow restriction and rheological modelling on blood-borne oxygen exchange with the confining walls. The wall mass transfer rates within the separated and reattached regions display a strong dependency on the used hemorheological model. Newtonian and non-Newtonian models result in a peak wall mass transfer rate within the recirculation region. However, non-Newtonian models that account for the yield stress and shear-thinning effects predict a substantial, highly localized, drop in the wall mass transfer rates of oxygen, at the reattachment point.