为探究低温流体池内核态沸腾机理,对液氮池内核态沸腾进行了计算流体力学(CFD)建模及实验研究。除了探究过热度和热流关系,重点分析过热度对气泡脱离直径和频率影响。根据实验观测,将核态沸腾过程分为3个阶段:低热流阶段;过渡沸腾阶段;完全核态沸腾(FDNB)阶段。基于得到的沸腾过程气泡直径及频率,构建了核态沸腾CFD数值模型,得到的过热度及热流密度关系,与实验测量得到的数据吻合。
To explore the mechanism of nucleate pool boiling of cryogenic fluids,an experimental apparatus was built to conduct a visualization study and verify the computational fluid dynamics( CFD) boiling model. Apart from the general measurements of the super-heat and heat flux,the influences of super-heat on bubble departure diameters were specially analyzed. Based on the observations,the whole nucleate boiling process from bubble formation to departure from the heated wall can be divided into three stages: low heat flux stage; transitional stage; fully developed nucleate boiling( FDNB) stage. CFD simulations with several existing correlations and the attained values from the experiments for the bubble diameter were finally conducted,and the results fitted well with the present experimental data.