EFFECT OF SINGLE- AND MULTI-HOLE BUBBLE BREAKERS ON THE EFFERVESCENT ATOMIZATION PROCESS

Effervescent atomization technique is used in many industrial applications such as gas turbines, internal combustion engines, furnaces and burners, and pharmaceutical sprays. The present study is focused on investigating the influence of a new type of bubble breaker on the two-phase flows inside and outside an effervescent atomizer. Different configurations (size and number of holes) of the new bubble breaker were considered over a range of gas to liquid flow rates ratios (GLRs) from 0.001 to 0.022. High-speed imaging was used to visualize and quantify bubble and spray characteristics. The results showed that the two-phase flow regime and bubbles' size inside the effervescent atomizer, and the spray droplets' size and velocity outside the atomizer are strongly influenced by the bubble breaker. The results demonstrated that the bubble breaker effectively fragments large bubbles into smaller ones. Furthermore, the results illustrate that the diameter and numbers of holes of the bubble breaker affect the bubble size inside the mixing zone as well as the droplet size and velocity.