变截面翅片通道内过冷沸腾可视化试验

以水为介质，对三角多孔翅片（TP）和横排锯齿翅片（TDS）两种变截面翅片通道的过冷沸腾进行了可视化试验。研究了体积流量、过冷度与热通量对过冷沸腾起始位置的影响，通过观察变截面翅片流道内单个气泡形成、生长与合并或脱离的过程，对比分析两种变截面翅片对流沸腾传热强化机理。试验结果表明：TDS翅片通道内气泡从出现到消失的平均周期约为TP翅片的一半；过冷沸腾起始位置随着体积流量的增大，逐渐向流道出口处移动；而随着热通量的增大和过冷度的减小逐渐靠近流道入口处；过冷度对过冷沸腾起始位置的影响比热通量对其的影响更大。

Visualized investigation of subcooled boiling in variable cross-section fin channels

The subcooled boiling of the two kinds of variable cross-section fin channels of triangular porous (TP) fin and transverse direction serrated(TDS) fin was visualized by water as working medium. The effects of volume flow, inlet subcooling degree and heat flux on the onset of the nucleate boiling were investigated. By observing the process of single bubble formation, growth and merging or disengagement in the variable cross-section fin channel, the boiling heat transfer enhancement mechanism was analyzed. The results show that the average cycle of bubbles from the appearance to disappearance in the TDS fin channel is around half of the TP fins; the onset of the nucleate boiling position gradually moves toward the outlet of the flow channel as the volume flow increases. By contrast, it gradually close to the inlet of the channel when the heat flux density increases and the inlet subcooling degree decreases. Furthermore, the effect of the inlet subcooling degree on the onset of the nucleate boiling is greater than that of the heat flux.