The largest diameter of falling drop in the up-gas flow

This study aimed to investigate the largest diameter of falling drop in the up-gas flow. Due to gravity, the falling drop is common in nature and industry. Drop breakup in the airflow is referred to as secondary atomization, found in numerous practical applications. Critical Weber number is the key dimensionless number marking the beginning of drop breakup. Herein, we explain the different critical Weber numbers between the free-fall raindrops breakup and secondary atomization based on the Rayleigh-Taylor (RT) instability. The theoretical criterion of largest raindrop size is proposed by RT wave number model. In addition, we suggest a map of falling drop size regions, which can well explain the phenomena of the super-large raindrop. The current study is also helpful in the remission of drop entrainment in the washing tower.

Automated summary

This study aims to investigate the largest diameter of falling drop in the up-gas flow. The phenomenon of drop breakup in the airflow, known as secondary atomization, is commonly observed in nature and industry. The critical Weber number is used to determine the beginning of drop breakup. This study explains the different critical Weber numbers for free-fall raindrops breakup and secondary atomization based on the Rayleigh-Taylor instability. The study proposes a theoretical criterion for the largest raindrop size and suggests a map of falling drop size regions to explain the occurrence of super-large raindrops. Additionally, the findings of this study have practical implications for reducing drop entrainment in washing towers.