Liquid Films Flowing Concurrently with Air in Horizontal Duct : 4th Report, Effect of the geometry of duct cross-section on liquid film flow

抄録

The effect of the aspect ratio of the duct cross-section on a liquid film flowing concurrently with an air stream was investigated using three horizontal ducts. The dimensions of the duct are 10 mm×40 mm (height×width), 40 mm×40 mm and 10 mm×80 mm. The results are summarized as follows: The boundary of flow patterns between the pebble wave flow and the disturbance wave flow strongly depends on the duct height. On the other hand, the boundary between a smooth surface flow and a two-dimensional wave flow as well as the nonwetting regime depends mainly on the duct width. The reason is that the volumetric flux of the liquid flow in the vicinity of the side walls of the duct is considerably larger than that in the central part of the duct width due to the formation of meniscus. Therefore, only the experimental values for the film parameters obtained at the central part of duct width are useful for comparison with the theoretical results obtained by the assumption that the flow is two-dimensional, even if the aspect ratio of duct seems to be sufficiently small.