Abstract:

Subcooled boiling model suitable for high pressure and high subcooling condition was established based on two-fluid model.The influence of liquid subcooling and wall heat flux on heat characteristics was investigated.The results show that distribution of gas phase throughout the cross section is nonuniform，and bubbles are intensive near the wall.The volume fraction increases with decreasing entrance subcooling which prompts the boiling heat transfer.With increasing heat flux，the surface heat transfer coefficient generally increases along the axial direction，however，decreasing tendency can be observed in local area，which becomes unclear with decreasing entrance subcooling.

Key words:

传热, 双流体模型, 过冷流动沸腾, 高过冷度

摘要：

基于双流体模型，建立了适合高压高过冷工况的过冷沸腾模型，考察了液体过冷度和壁面热通量对垂直圆管内气液两相传热特性的影响。结果表明，高过冷度下整个截面上气相分布十分不均匀，壁面附近气泡比较密集。随着入口过冷度的减小，气相体积分数增加，促进了沸腾传热的发展。随着壁面热通量的增加，表面传热系数沿流体流动方向总体上呈增大趋势，局部区域内出现下降，并且传热系数的下降趋势随入口过冷度的减小逐渐变得不明显。

关键词:

传热, 双流体模型, 过冷流动沸腾, 高过冷度