Valitov, G;
Rossi, D;
Price, C;
Gavriilidis, A;
Mazzei, L;
(2022)
Axial dispersion in curved channels in the presence of pulsating flow.
Chemical Engineering and Processing - Process Intensification
, 180
, Article 108629. 10.1016/j.cep.2021.108629.
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Abstract
A narrow residence time distribution (RTD) is desirable in several chemical engineering processes. However, in systems operating at low Reynolds number, axial dispersion can be significant. To lower it, we utilised two mixing approaches: secondary flow achieved with curved geometries and oscillatory variation of the flow rate. We investigated their combined effect on axial dispersion in millifluidic channels with three geometries: straight tube, helically coiled tube (HCT) and coiled flow inverter (CFI). We studied the influence on axial dispersion of two key parameters of pulsating flows: amplitude and frequency of pulsation; in dimensionless form, these are expressed via the amplitude ratio and Strouhal number, respectively. For unsteady flow, we performed numerical simulations to characterise mixing. The results indicate that pulsation enhances radial mixing significantly. Our experimental studies show that axial dispersion is lower in the presence of pulsation, and increasing amplitude and/or frequency has a positive effect. For the same amplitude ratio and Strouhal number, axial dispersion decreases more in the CFIs than in the HCTs. Comparing two extremes, the straight capillary with steady flow (no RTD enhancement) and the CFI with pulsation (lowest axial dispersion achieved in our work), we observed a 10-fold reduction in the axial dispersion number.
| Type: | Article |
|---|---|
| Title: | Axial dispersion in curved channels in the presence of pulsating flow |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.cep.2021.108629 |
| Publisher version: | https://doi.org/10.1016/j.cep.2021.108629 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Coiled flow inverter, Helically coiled tube, Axial dispersion, Residence time distribution, Microfluidics, Oscillatory flow |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10135131 |
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