汽液固三相蒸发管内防除垢的数值模拟

假设汽液固三相循环流化床蒸发管内均匀覆盖一定厚度的硫酸钙结晶垢层,考虑垢层与流体间的耦合换热、管内流体泡核沸腾传热、汽液两相流体对垢层的剥蚀以及颗粒对垢层的碰撞磨损作用,初步建立了汽液固三相流系统防除垢的模型,并应用STAR-CCM+软件对其进行了数值模拟.结果表明,垢层表面温度和汽含率、污垢剥蚀速率以及颗粒对垢层的磨损速率都是影响汽液固三相蒸发管内防除垢的重要因素;增加表观流速和固体颗粒体积分数,可以降低垢层表面温度和汽含率、提高污垢剥蚀速率和磨损速率,进而可以强化蒸发管内的防除垢效果.

Numerical simulation of fouling prevention and cleanup in vapor-liquid-solid three-phase evaporation tube

Assuming vapor-liquid-solid three-phase fluidized bed evaporation tube covered the certain thickness crystallization calcium sulfate fouling layer uniformly,considering the coupling heat exchange between the fouling layer and the fluid,nucleate boiling heat transfer mechanism in fluid,denudation between vapor-liquid two-phase flow and the fouling layer,collision or erosion between particle and fouling layer,established fouling prevention and cleanup model of vapor-liquid-solid three-phase flow system preliminarily.The STAR-CCM + software is applied to simulate it,the results show that the fouling layer surface temperature and volume fraction of vapor,fouling denudation rate and erosion rate between particle and fouling layer were all important factors which affect fouling prevention and cleanup in vapor-liquid-solid three-phase evaporation tube;with the increase of velocity and volume fraction of solid particle,the fouling surface temperature and volume fraction of vapor reduced,the fouling denudation rate and erosion rate between particle and fouling layer improved,then can strengthen fouling prevention and cleanup effect.