不凝气体对蒸汽射流冷凝影响的数值研究  

Numerical investigation of influence of non-condensable gas on steam jet condensation

作　　者：李海波 田茂诚[1] 屈晓航 LI Haibo;TIAN Maocheng;QU Xiaohang(School of Energy and Power Engineering,Shandong University,Jinan 250061,Shandong,China;School of Transportation and Vehicle Engineering,Shandong University of Technology,Zibo 255049,Shandong,China)

机构地区：[1]山东大学能源与动力工程学院,山东济南250061 [2]山东理工大学交通与车辆工程学院,山东淄博255049

出　　处：《化工学报》2020年第S02期135-141,共7页CIESC Journal

基　　金：国家自然科学基金项目(51676114)。

摘　　要：通过二维轴对称数值模型研究了空气等不凝性气体对蒸汽射流与过冷水直接接触冷凝行为和传热特性的影响。采用CFX中的欧拉-欧拉双流体模型,结合热相变模型计算蒸汽的冷凝量、组分传递模型计算混合气体中组分的变化量;喷嘴出口的气体质量流量为300 kg/(m2·s),不凝气体含量在15%以内。结果表明,不凝气体阻碍了蒸汽与过冷水直接接触,形成热阻,恶化了冷凝传热,且热阻随不凝气体含量增加而增加;冷凝速率随不凝气体含量增加而减小;射流区长度随不凝气体含量增加而增加;不凝气体的存在,使水蒸气不能被完全冷凝,而剩余水蒸气的含量与初始不凝气体含量无关。The influence of non-condensable gas on the direct contact condensing behavior and heat transfer characteristics of steam jet in subcooled water is investigated by two-dimensional axisymmetric numerical model.Based on Euler-Euler two-fluid model in CFX,the steam condensation is calculated with thermal phase change model.The composition variation of steam-air mixture is realized using species transport equation for the gas phase.The gas mass flow at nozzle outlet is 300 kg/(m2·s),and non-condensable gas is within 15%.The results show that non-condensable gas obstructs the direct contact between steam and subcooled water,forming the thermal resistance and deteriorating the condensation heat transfer.The thermal resistance and the length of jet region increase with the increase of non-condensable gas.While the condensation rate decreases with the increase of noncondensable gas.The presence of non-condensable gas prevents vapor from being condensed completely,and the remaining vapor is independent of the original non-condensable gas.

关 键 词：直接接触冷凝 不凝气体 两相流 计算流体力学 

分 类 号：TK124[动力工程及工程热物理—工程热物理]