Identification of Flow Regimes in a Flat Gas-liquid Bubble Column via Wavelet Transform

A flat bubble column reactor is studied experimentally to increase the understanding of flow regimes and their transitions. To perform this, qualitative observations and global gas hold-up measurements are used to detect flow regime transitions. Liquid velocities are measured with Laser Doppler Anemometry (LDA). However, as these signals contain a huge amount of information, it is necessary to use signal treatment techniques to analyse them. Wavelet transform was employed in the present paper. The results show that this technique is a powerful tool to (i) describe liquid flow macrostructures, (ii) study gas distributor effects and consequently, (iii) identify flow regimes.