The removal characteristics of oil from narrow spaces using microbubbles were experimentally investigated. To make the narrow space, a steel plate, and a glass plate inserted a thin spacer were used. The experiments were conducted by varying the types of bubbles and the angle of narrow space against the vertical direction. Bubble types were tested for millimeter-sized bubbles and mixed conditions of millimeter-sized bubbles and microbubbles expected not only the microbubbles. A mixed condition of millimeter-size bubbles and microbubbles was most effective in removing the oil. It was also shown that microbubbles were effective to some extent in removing the oil at angular conditions where millimeter-sized bubbles were unable to remove it.
Murata et al. (Wed,) studied this question.