1996 年 62 巻 600 号 p. 2972-2977
Experinlental investigations arc performed on flooding which occurs in vertical circular and annular channels. Water film flows down along the channel surface through porous cylinders, and air is raised from the channel bottom by a suction pump. The ooding velocity of the circular tube is proportional to the diameter ill agreement with earlier investigations For the annular channel, a ratio of liquid flow rates of both channel surfaces has a strong effect on the flooding velocity. The conventional method cannot predict the flooding velocity. In the present study, a characteristic diameter of the annular channel is determined by the ratio of liquid flow rates for Reynolds number of liquid and gas. The flooding velocity is approximately indicated as a uniform curvature with the Reynolds number of liquid.