气液叉流竖管降膜热质塔的传热传质数值模拟

Numerical Simulation of Heat and Mass Transfer in Thermal Mass Tower with Vertical Tube Falling Film under Gas-liquid Cross Flow Condition

建立气液叉流条件下,竖管降膜传热传质的溶液-水蒸气-空气多相流模型,对单根竖管降膜传热传质过程进行了数值模拟,探讨不同气流速度下管外液膜分布及热质传递规律。随着横掠气流速度的增大,管外液膜迎风侧出现破断,且破断点随气流速度增大迅速上移;各管段蒸发量由上往下呈递减趋势;管壁总换热量和蒸发量随气流速度的增大先增大后减小,管壁换热量在气流速度为0.3 m/s时达最大值,液膜蒸发量在气流速度为0.6 m/s时达最大值。

The solution-steam-air multiphase flow model for heat and mass transfer in vertical tube failing film under gas-liquid cross flow condition is set up. Numerical simulation of heat and mass transfer process in single vertical tube falling film is performed. The distribution of falling film outside vertical tube and the rule of its heat and mass transfer at different air ve- locities are discussed. With the increase of horizontal air velocity, the rupture takes place at the windward side of the falling film outside the vertical tube, and the rupture point moves up rapidly with the increase of air velocity. The evaporation rate of tube sections is in a decreasing trend from the top of the tube to the bottom, the total heat transfer rate and evaporation rate of the tube wall increase first and then decrease with the in- crease of air velocity. The maximum heat transfer of tube wall is reached at the air velocity of 0.3 m/s, and the maximum evaporation rate of liquid film is reached at the air velocity of 0.6 m/s.