The uniform and isometric tube configuration was adopted in most flooded evaporators[7]. The bubbles generated on the tube surfaces move upwards and leave the tubes through the interspace between tubes. However, in the actual working conditions, the small bubbles generated on the surface of the tubes will adhere to the tube walls, which will deteriorate the heat transfer. Especially for the heat exchange tubes near the liquid surface, large amounts of small bubbles flowing upwards may accumulate and form large bubbles and thus block the clearances between tubes