Abstract
A velocity slip between the gas and the liquid phases due to the density difference lowers the conversion efficiency of the nozzle. On the other hand, the velocity slip between micro-bubbles and the liquid around it is generally small. In the study, the pressurized dissolution method and its modified method were used to generate micro-bubbles. In the modified pressurized dissolution method, an orifice plate was located before the nozzle to make micro-bubbles and it was found that the flow was supersonic in the diverging part of the nozzle. Furthermore, the effect of the amount of the dissolved gas on the flow was studied. The void fraction of the flow was increased as the amount of the dissolved gas but the volume of a single bubble at the throat did not change. The calculation of sound speed was carried out to compare with the throat velocity for determination of the flow condition.
