Abstract: Based on the equal Morton number and inclusion movement similarity， the polyethylene particle was employed to simulate inclusions in liquid steel. The high speed video-photography was used to record the movement of bubble and inclusion. The mechanism of inclusion removal by bubble trailing vortex was analyzed. The experimental results show that there are two kinds of inclusion trajectories under bubble trailing vortex. One is that the inclusions approach to the bubble trailing vortex under both sides of bubble and enter the bubble trailing vortex zone， then float with a greater velocity before leaving the bubble trailing vortex zone. The other is that the inclusions above the bubble move to the bubble rear in a circuit manner without collision or attachment each other， then float with bubble in the trailing vortex and rise helically along the vertical direction. On the condition of the same floatation distance， the effect of the larger bubble trailing vortex on inclusion removal is better than that of the smaller bubble.

Key words: bubble, trailing vortex, inclusion, liquid steel, physical simulation