Abstract:The heat transfer characteristics of flow boiling in the cylindrical micro-fin channel with constant heat flux at the bottom were numerically studied,which was based on the VOF flow model coupled with boiling heat and mass transfer model.To capture the movement of vapor-liquid interface by the geo-reconstruction method,this article studied the partial velocity variation of two-phase interface.Simultaneously,it analyzed the effect of rib height on the morphology of bubbles,flow boiling heat transfer characteristics and boiling instability in the micro-channel.The results show that the presence of micro-columns increases the density of bubble nucleation point.The bubbles movement increases the possibility of contact between working medium and heating wall.When the height of rib is low,the capillary force generated by the secondary channel is weak and air bubbles are not easy to escape.This can lead to locally abnormal overheating and cause the heat transfer to deteriorate.Reversing flow of the bubbles is blocked by micro-fin array,and the boiling instability is reduced.However,over-hight micro-fin can lead to oscillate heat transfer system,thus affecting the reliability of heat transfer.