空气横掠叉排降膜管束的压降特性

摘要

建立空气横掠叉排降膜管束的压降测试平台,实验研究工况参数(喷淋密度、入口风速)和结构参数(纵向节径比、横向节径比、管外径)对空气横掠叉排降膜管束的空气侧压降的影响.结果表明:喷淋密度对压降的影响较小,喷淋密度每增大0.02 kg/(m·s),单排管压降仅增大约15％;当入口风速大于3.2 m/s时,部分管束出现表面水膜被强风吹脱的现象,导致实验测量压降大幅增加;相较纵向节径比,横向节径比与管径对压降影响较大,其中横向节径比每减小0.3,平均单排管压降增大约30％.拟合平均单排管压降与喷淋密度、入口风速、纵向节径比、横向节径比及管外径的关系式,拟合误差≤20％.%An experimental platform for air flowing across falling-film staggered tube bundle is set up.The experiments are carried out to research the influence on the pressure drop of the air side when air flowing across falling-film staggered tube bundle by different operation parameters (including spraying density and inlet air velocity),and structural parameters (including transversal pitch diameter ratio,longitudinal pitch diameter ratio and external diameter of tube).The results show that the spraying density affects the pressure drop slightly,for example,the pressure drop of single row tube just increases by about 15％ when spraying density increases 0.02 kg/(m · s).When the inlet air velocity is faster than 3.2 m/s,the water film can be blown off from a part of tubes,which greatly increases the experimental values of pressure drop.Compared with the longitudinal pitch diameter ratio,the transversal pitch diameter ratio and tube diameter have significant impacts on the pressure drop.When the transversal pitch diameter ratio decreases 0.3,the average pressure drop of single row tube increases by about 30％.Meanwhile,a pressure drop correlation for single row tube among the spraying density,inlet air velocity,transversal pitch diameter ratio,longitudinal pitch diameter ratio and external diameter of tube is proposed,whose fitting error is less than 20％.