垂直上昇気液環状流における平均液膜厚さと界面せん断応力に及ぼす表面張力低下の影響

抄録

The purpose of this study is to investigate experimentally the effects of reducing surface tension on the liquid film structure and interfacial shear stress in vertical-upward air-liquids annular flows in a 19.2 mm i.d. and 5.4 m long circular tube. The test liquids were water and polyoxyethylene-lauryl-ether-water solution, and the surface tension of these liquids ranged from 72 to 45 dyne/cm. The liquid film structure was observed using the still photography and the maps of time and spatial characteristics of peripheral-mean liquid holdup detected with a series of 63 liquid holdup sensors each axially 15 mm apart in a constant current method. In the present paper, it was first described that the liquid film structure strongly depends on the reduced surface tension. Next, the effects of the reducing surface tension on the mean liquid film thickness, the gas-liquid interfacial shear stress and the interfacial friction factor were discussed with relation to the result of the observation of liquid film structure.