多通道烘缸汽液两相流型特性及转变

Characteristics and Transition of Steam-liquid Two-phase Flow Patterns inside Multi-channel Cylinder Dryer

本研究以实验条件下多通道烘缸蒸汽凝结换热工作状态为基础,通过可视化观察,研究了水平U形截面通道汽液两相界面分布情况及流动特性。结果表明,通道内蒸汽凝结流动主要有7种流型,发生稳定凝结换热过程的主要区域仍然是传热效果较好的环状流;环状流占据范围会随着操作参数的变化而变化,而最佳的蒸汽质量通量与冷却水质量流量的匹配关系是35 kg/(m^(2)·s)与198 kg/h;换热热流密度会影响环状流转变位置,但不同蒸汽饱和温度下,换热热流密度对环状流占据范围的影响趋势不同。

This study was based on the working state of steam condensation heat transfer in a multi-channel cylinder dryer under experimental conditions. Through visualization experiments,the distribution and flow characteristics of the steam-liquid two-phase interface in the horizontal U-shaped cross-section channel were studied. The results showed that there were seven main flow patterns in the steam condensation flow,and the main area where the stable condensation heat transfer occurs was still the annular flow with better heat transfer effect. Meanwhile,the occupied area of the annular flow varied with the operating parameters,and the optimal matching relationship between the steam mass flux and the cooling water mass flow was 35 kg/(m^(2)·s)and 198 kg/h. The heat flux would affect the transition position of the annular flow,but the effect of the heat transfer heat flux on the area of annular flow was different under different steam saturation temperatures.