Acoustic resonance and atomization for gas-liquid systems in microreactors

Highlights • Acoustic resonance within a liquid slug in gas–liquid Taylor flow was demonstrated. • Intense atomization was observed with slug resonance. • Visual evidence of the cavitation-wave hypothesis was provided.
It is shown that a liquid slug in gas–liquid segmented flow in microchannels can act as an acoustic resonator to disperse large amounts of small liquid droplets, commonly referred to as atomization, into the gas phase. We investigate the principles of acoustic resonance within a liquid slug through experimental analysis and numerical simulation. A mechanism of atomization in the confined channels and a hypothesis based on high-speed image analysis that links acoustic resonance within a liquid slug with the observed atomization is proposed. The observed phenomenon provides a novel source of confined micro sprays and could be an avenue, amongst others, to overcome mass transfer limitations for gas–liquid processes in flow.