垂直向上圆管环状流临界热流密度研究

Investigation of Critical Heat Flux of Annular Flow in Vertical Upward Round Tube

预测高含汽量下的临界热流密度对于直流蒸汽发生器和事故工况下反应堆堆芯的安全性具有工程价值。本文基于液滴夹带、沉积和液膜蒸发理论,对垂直向上的均匀加热圆管内环状流的液膜厚度和液膜质量流速沿轴向的变化进行了预测。结果表明,当液膜蒸干时,干涸发生,此时的热流密度即为临界热流密度。将理论计算的临界热流密度值与实测值相比较,实验数据偏高,偏差在30%以内。

Prediction of Critical Heat Flux at high mass quality is important for the safety of oncethrough steam generator and the reactor core under accidental conditions. Based on the theory for droplet entrainment, droplet deposition and liquid film evaporation, the film thickness and film mass flow rate distribution along axis are calculated at vertical upward round tube. The dryout emerges at the point where the film is depleted due to the balance of entrainment, deposition and evaporation. The theoretical CHF values are higher than that of experimental data, with error within 30%.