复合喷动塔内蒸发特性的数值模拟与实验研究

分析了描述喷动塔内气液流动、雾化、蒸发、碰壁的数学模型,运用上述模型模拟脱硫塔内蒸发特性,得到了入口介质条件对塔内蒸发特性及液相水含量的影响,通过与实验值比较验证了模型的可靠性。模拟结果表明:液滴蒸发强度呈现先升高后降低趋势,在距离喷嘴300 mm处达到最大值;在一、二级塔体交界处,由于受多级喷动结构影响,液滴蒸发速率明显升高;液滴截面质量流率沿塔体轴向逐渐降低,在1 500 m处基本蒸发完毕;蒸发强度与喷嘴雾化压力呈非单调关系,烟气温度和含湿量对一级塔内液态水含量有3倍~5倍的影响;数值模拟结果与实验值基本一致,可以作为研究塔内液滴蒸发特性的有效工具。

NUMERICAL SIMULATION AND EXPERIMENTAL STUDY ON EVAPORATION CHARACTERISTICS IN MULTI-SPOUTED BED

The mathematic models of gas and droplet flow, droplet atomization, evaporation, and impingement were analysed. The evaporation characteristics were got under different medium conditions, such as flue gas temperature, atomization pressure and flue gas relative humidity. In order to validate the reliability of the models used, the experiment was done. The simulation results indicate that evaporating intensity reaches its peak value in the area of 300 mm away from the sprayer. Due to the multi-spouted configuration,droplet concentration increases obviously in the intersecting region between the first and second reaction region. Droplet intersection mass flow rate reduces along the axis, and droplets are completely evaporated at 1 500 mm away from the sprayer. The relation between the evaporation rate and atomization pressure is non-linear. The flue gas temperature and relative humidity can raise the water volume by 3 ～ 5 times under the given conditions. The comparison between the numerical and experimental results demonstrates the availability of the model in predicting droplet evaporation.