分岐管を用いた新しい気泡除去技術の基礎研究

抄録

Bubbles in the pipe flow cause flow unsteadiness, noise and vibration. Common bubble removal technique makes use of the buoyant force. However, under microgravity condition, the buoyant force doesn't act on the bubbles. In this paper, we performed a basic research for a novel bubble removal technique using a branching pipe with a pressure difference. The microgravity experiment was performed in the underground microgravity experiment center ( JAMIC) in Kamisunagawa-cho, Hokkaido. Bubble behavior in a branching pipe under a microgravity condition was investigated by an air-water loop system installed in a free fall capsule. As a result of the experiments, the number of bubbles ‰owed into the branching pipe increased as the bubble diameter increased. When the mean diameter of bubble was over 3.0 mm, 80 of the bubbles were able to ‰ow into the branching pipe. This is because a bubble with a large diameter experiences the large body force caused by the pressure difference between the main and the branching pipe. This pressure difference was generated by the flow separation, which occurred in the entrance of the branching pipe. This tendency was more intensified under a normal gravity condition.