An experimental investigation on role of turbulence modulation induced by thread structure in coaxial air blast atomization of a surfactant-laden jet

This study aims to utilize the high-speed flow visualization and droplet size analysis technology to experimentally investigate the effects of surfactant concentration and thread induced turbulence modulation on the coaxial jet atomization characteristics. After adding turbulence modulation, a larger initial amplitude appeared on the jet surface, which is the reason for the reduction in breakup length and droplet size. Due to the Marangoni effect and capillary pressure, the breakup length increases overall with the increase of surfactant concentration, except for a sudden decrease at the critical micelle concentration (CMC). The droplet size generated by the jet disintegration shows a nonmonotonic trend with the surfactant concentration, reaching the minimum value at CMC. Finally, the results indicate that an increase in the pitch of thread structure leads to a better atomization performance.