Chemical Engineering Journal, Vol.313, 807-814, 2017
High-efficiency mixing process in secondary rotating stream
Primary rotating flow (PRF) and secondary rotating stream (SRS) are two basic rotating flow patterns. We compared their mixing performances via the iodine transfer process from CCI4 to water. When the mixing power consumptions of the SRS mixer and PRF blender were approximated, the maximum value of K alpha(SRS) exceeded 71.7 s(-1). (K alpha) over bar (SRS) was higher than (K alpha) over bar (PRF) 3 orders of magnitude, but the total energy consumption of the SRS mixer was lower than that of the PRF blender 2 orders of magnitude. It was also found that (K alpha) over bar (SRS) increased sharply with the decrease of r, which is consistent with the typical characteristics of Higee technology. Furthermore, computational fluid dynamics (CFD) was applied to simulate the pressure and flow field distributions of SRS. Based on the analysis of the velocity distribution mappings, it is concluded that SRS spontaneously generates intensive convection and vigorous shear stress under the reversing high-gravity field. The curve of K alpha C-SRS versus semi-circle channels is composed of a peak line and a wave line. In theory, we systematically illustrated the reasons for the high efficiency of SRS from four perspectives: time mixing, thermodynamics, momentum and mass transfers, opposite energy flows. Having many advantages and potentials, SRS will be widely explored and applied in chemical engineering field. (C) 2016 Elsevier B.V. All rights reserved.SRS
Keywords:Secondary rotating stream;Reversing high-gravity field;Multiscale mixings;Mass transfer;Computational fluid dynamics (CFD);Process intensification