A Fundamental Study of Aeration in Oil : Effect of Air Diffusion on the Change in Bubble Diameter

抄録

In this paper we present the analytical and experimental results on the effect of air diffusion of a single spherical bubble in oil for both cases when pressure change as well as rotational fluid motion is present or absent. We measured the change in diameter in a case without pressure change and confirmed that an existing theory was useful when the dissolved air was initially undersaturated, if a suitable value of the air diffusivity affected by the rotational motion and the fluid temperature could be chosen. On the change in diameter in a case with pressure change, we confirmed analytically and experimentally that under a certain condition the bubbles grown under low pressure needed a long period of time to return to the initial diameter when the pressure was restored to the atmospheric one.