The uniform and isometric tube configuration was adopted in most flooded evaporators[7]. The bubbles generatedon the tube surfaces move upwards and leave the tubes through the interspace between tubes. However, in the actualworking conditions, the small bubbles generated on the surface of the tubes will adhere to the tube walls, which willdeteriorate the heat transfer. Especially for the heat exchange tubes near the liquid surface, large amounts of smallbubbles flowing upwards may accumulate and form large bubbles and thus block the clearances between tubes. Inextreme situations, the bubbles will form gas film surrounding the heat exchange tube and significantly deteriorate theheat transfer[8]. To solve this problem, a configuration that can effectively guide the small bubbles out of the heatexchange tubes should be redesigned and optimized