Visualized Study on Interface Shape and Growth of Sliding Bubble in Narrow Rectangular Channel

Sliding bubble interface shape and bubble growth for the isolated bubble region in a narrow rectangular channel were observed from the wide side and narrow side of the narrow rectangular channel using a high speed digital camera.The results show that the growth rate of sliding bubble is small,and the growth rate of a small bubble is slightly larger than that of a large bubble.The sliding bubble appears to be spherical in shape according to the observation from the wide side of the narrow rectangular channel,but the sliding bubble is elongated in the direction normal to the heating surface from the side view.During the process of sliding bubble along the heating surface,the upstream and downstream contact angles are almost equal in this experimental condition.