気液界面を通しての炭酸ガス輸送に及ぼす界面重油汚れの影響(<小特集>異相界面における諸現象の物理)

抄録

The effects of heavy-oil surface contamination on the CO₂ transfer across the air-water interface were investigated through laboratory experiments in an oscillating-grid tank. The CO₂ transfer velocities across the air-water interface contaminated with heavy-oil were estimated for both tap water and saltwater. The results show that the CO₂ transfer volocity across the non-breaking interface for tap water contaminated with heavy-oil is damped to 30% of that for tap water without heavy-oil contamination. The CO₂ transfer velocity across the non-breaking interface for 3.5 wt% saltwater (or natural seawater) contaminated with heavy-oil is damped to 46% of that for 3.5 wt% saltwater (or natural seawater) without heavy-oil contamination. The reduction in the CO₂ transfer velocity can well be explained by assuming the resistance equivalent for tap water and saltwater to mass transfer due to a thin oil film on the surface. When the interface is intensively broken, the CO₂ transfer velocity across the air-water interface contaminated with heavy-oil approaches to that for tap water or saltwater without heavy-oil contamination. The reduction in the CO₂ transfer velocity across the air-water interfaces suggests that the effects of the surface contamination should be taken into account in the General Circulation Model (GCM) for estimating the global CO₂ budget.