基于可视化试验的板翅通道内过冷沸腾汽泡行为分析

Using water as working medium, the forced convective subcooled boiling in variable cross-section fin channels of plate-fin heat exchanger: transverse direction serrated fin (TDS) and triangular porous (TP) were visualized. The effect of inlet subcooling degree on the nucleation site number was analyzed. The effect of heat flux, volume flow and inlet subcooling degree on the bubble departure diameter was examined. The mechanism of boiling enhancement heat transfer in the variable cross section fin channel was explored by observing the forced convective subcooled boiling flow pattern. The result shows that the subcooled boiling flow patterns in the TP and TDS fin channel are similar. It includes bubble formation area, the bubble development area and the bubble disappearance zone. The average bubble departure diameter in the variable cross section channel decreases by the increasing of volume flow rate and inlet subcooling degree, enlarging with the reducing of heat flux. The nucleation site number in the TP fin channel is more than that of the TDS fin channel at the same conditions. The average bubble departure diameter in the TDS fin channel is about 1.4 times bigger than that of the TP fin channel.