Formation map of air-liquid hollow profile under microgravity

From the viewpoint of oxygen recovery and supply in a space station, the fo rmation of an air-liquid hollow profile which has a suitable interface shap e to cultivate microalgae under microgravity conditions is experimentally i nvestigated. The air-liquid interface profiles in a rotating vessel were? o bserved and recorded. The effects of the modified Weber number and modified Reynolds number on formation of the air-liquid hollow profile were experim entally investigated. We developed a basis for judging conditions forming t he air-liquid hollow profile from the video images, When the volume ratio o f the liquid/ vessel is 0.60 and the modified Weber number is greater than 2.2, it is found that the air-liquid hollow profile forms and is independen t of the modified Reynolds number. From the experimental results using liqu ids with different surface tension, the validity of using the modified Webe r number is confirmed as a dimensionless number for judging the formation o f the air-liquid hollow profile. It is experimentally found that the format ion conditions for the air-liquid hollow profile under microgravity can be determined by the modified Weber number and the volume ratio of the liquid/ vessel. In a map of the volume ratio of the liquid/vessel vs. the modified Weber number, the discrimination of the formation of the air-liquid hollow profile is performed by a line experimentally obtained in this study.