The effects of inlet conditions on mass transfer in annular swirling decaying flow

Abstract

Wall to liquid mass transfer coefficients are experimentally investigated, with an electrochemical method, in an annular swirling flow generated by a tangential inlet. Attention is focused on the influence of the ratio of the annular thickness e to the inlet diameter φ e . According to the value of this ratio, three categories of flow regimes are obtained: the pure swirl flow, for φ e = e, the contraction swirl flow, for φ e > e and the expansion swirl flow, for φ e < e. The other parameters of the study are the mean axial distance of the mass transfer surfaces, to characterize the swirl decay, the Reynolds number based on the hydraulic diameter and the geometric factors of the annulus. Correlations of the experimental data, taking into account the aforementioned parameters, are proposed for laminar and turbulent swirling flows.