Characterization of Multiphase Flow Using Wire-Mesh Sensor (WMS)

Packed and bubble columns represent important multiphase contactors utilized for reaction and separation in chemical engineering. The analysis of the hydrodynamic behavior of such multiphase apparatuses is usually done by assessing important hydrodynamic parameters such as superficial liquid and gas flow velocities and gas/liquid hold-up. However, those parameters are not capable to explain the real behavior, since interactions between phases are very complex. As a consequence, a large variety of probe technologies have been developed in the last decade. However, all these methods have the disadvantage that only few of the probes could be implemented in a cross section to avoid a significant influence on the interaction of the gas and liquid phases. Other non-intrusive techniques like tomography avoids these restrictions, but experiments using such methods are in most cases limited in terms of a temporal and/or spatial resolution of small diameters and thus are not representative for production scale dimensions. The local liquid and gas hold-up and their distribution were measured with the wire-mesh sensor (WMS) technology applied in bubble columns as well as in packed columns. The sensor can be used to measure transient phase fraction distributions in cross-sectional flow and is able to discriminate fluids having different relative permittivity (dielectric constant) in multiphase flow.