Effect of bubble-breaker geometry on spray parameters of effervescent atomizer: preliminary study

článek ve sborníku mimo WoS a Scopus

en

The quality of spray generated by an effervescent atomizer depends on the internal flow structure, specifically, on the size and frequency of air bubbles and the type of flow structure. Smaller bubbles lead to a more stable spray with finer droplets. This paper aims to experimentally investigate the effect of bubble breakers in the mixing chamber. The bubble breaker should disintegrate large bubbles and create a stream of small ones or mix liquid and gas if a slug or annular flow occurs. Four different bubble breakers were used; perforated plates with a pore size of 0.5 or 1.5 mm, a porous mesh with a gyroid structure and a swirl insert. Droplet sizes were measured using the shadow size technique. Bubble breakers were found to alter the fluctuation rate of the atomizer operated at a constant air pressure of 100 kPa and gas-to-liquid ratios from 2 to 10%. Inserts generate a pressure loss, which result in reduction in discharge coefficient, CD. Moreover, a decrease in the fluctuation rate of liquid pressure also reduce CD. A more stable internal flow positively influences droplet sizes.

The quality of spray generated by an effervescent atomizer depends on the internal flow structure, specifically, on the size and frequency of air bubbles and the type of flow structure. Smaller bubbles lead to a more stable spray with finer droplets. This paper aims to experimentally investigate the effect of bubble breakers in the mixing chamber. The bubble breaker should disintegrate large bubbles and create a stream of small ones or mix liquid and gas if a slug or annular flow occurs. Four different bubble breakers were used; perforated plates with a pore size of 0.5 or 1.5 mm, a porous mesh with a gyroid structure and a swirl insert. Droplet sizes were measured using the shadow size technique. Bubble breakers were found to alter the fluctuation rate of the atomizer operated at a constant air pressure of 100 kPa and gas-to-liquid ratios from 2 to 10%. Inserts generate a pressure loss, which result in reduction in discharge coefficient, CD. Moreover, a decrease in the fluctuation rate of liquid pressure also reduce CD. A more stable internal flow positively influences droplet sizes.

Effervescent, insert, breaker, droplet, spray

23.06.2024

ICLASS

Shanghai

1–7

7