Dispersion in fully developed flow through regular porous structures: Experiments with wire-mesh sensors

• Published in: Chemical engineering and processing 2013-07, Vol.69, p.104-111
• Main Authors: Häfeli, R., Hutter, C., Damsohn, M., Prasser, H.-M., Rudolf von Rohr, Ph
• Format: Article
• Language: English
• Subjects: Axial dispersion; Length effect; Porous media; Turbulence; Wire-mesh sensor
• ISSN: 0255-2701; 1873-3204
• DOI: 10.1016/j.cep.2013.03.006

•Axial dispersion measured by wire-mesh sensors.•Length dependence of dispersion coefficient is confirmed.•Gradual build-up of turbulence is identified as an effect leading to length dependence.•Radial mixing measurement by wire-mesh sensor and by laser induced fluorescence. Within this study the wire-mesh sensor is proposed as a suitable device to investigate radial and axial dispersion in tubular reactors. Axial dispersion in turbulent flow through a regular highly porous structure is addressed and the effect of reactor length on the estimated axial dispersion coefficient is discussed. We state that the gradual increase of turbulence intensity in the entrance section of the porous structure is an effect which leads to a length dependence of the dispersion coefficient. Furthermore, we present measurements of radial mixing by the wire-mesh sensor and compare it to reference measurements using laser induced fluorescence. By that we discuss the possible bias from non-homogeneous tracer distribution between the electrodes. Despite the differences of the measurement principles we found a good qualitative agreement between the results.