Phase transition heat exchange is widely used in heat transfer.The thick liquid film formed during phase transition is the reason for worsening condensation heat transfer.The passive phase separation concept using mesh construction on the pipe wall was proposed to modulate the flow pattern for the first time.In order to verify the novel concept

air-water two-phase flow experiment was performed.It was found that part of the liquid could be separated and removed from the pipe and the contact area between air and tube wall was increased.The length ratio of gas and liquid increased oscillatorily after multi-stage modulation

and furthermore

slug flow pattern changed to stratified flow.With the decrease of liquid velocity or the increase of gas velocity the modulation effect was enhanced.According to the result of the adiabatic two-phase flow pattern modulation

it was expected that the structure would significantly enhance phase transition heat transfer performance.