摘要
以多级闪蒸海水淡化预热器为研究对象,运用Fluent软件对换热管内的析晶污垢形成过程进行数值模拟。通过编写UDF在控制方程中添加组分源项,修正流体组分的浓度分布,同时考虑H_2O分子对析晶污垢生成速率的贡献,使模拟结果更符合实际情况。探讨了流速、壁面温度对污垢形成速率的影响以及管道径向和轴向方向的析晶规律。以CaSO_4·2H_2O污垢在换热管表面的形成过程为例,验证了提出的模型和求解方法。结果表明:污垢的净生成率随管内流速的增大而降低,随壁面温度的增大而显著增大,且流速的适宜取值范围为1.0~1.5m/s;污垢热阻随管内流速的增大而减小。沿径向方向即从管道中心到管壁,污垢生成速率逐渐增大,而沿轴向方向,管子入口处的污垢净生成率最小。
The fouling process of crystallization in the pre-heater of multi-stage flash was simulated using the CFD code FLUENT.The concentration distribution in the heat exchanger tube was modified by editing UDF to add component source terms to flow-controlled equations.At the same time,the contribution of H2O to the fouling rate was considered to provide more exact description of the complicated fouling process.The effects of velocity and tube wall temperature on the fouling rate were investigated and the distribution rule of the crystallization fouling along the radical and axial direction was discussed.A case study of CaSO4·2H2O crystallization fouling process on the heat surface was adopted to test and verify the proposed model and solving method.The result shows that the fouling net generation rate decreases with the increment of velocity and increased with the increment of the wall temperature.The optimum range of velocity is 1.0~1.5 m/s considering both fouling and energy consumption.The fouling thermal resistance decreases when the velocity increased.In addition,the fouling generation rate increased generally along the radical direction of tube from center to wall,which was usually bigger inlet than inside along the axial direction.
作者
吕恒花
伍联营
胡仰栋
LV Heng-Hua;WU Lian-Ying;HU Yang-Dong(Key laboratory of marine chemistry theory and technology,Ministry of Education,Ocean University of China,Qingdao 266100,China;College of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China)
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第4期73-80,133,共9页
Periodical of Ocean University of China
基金
国家自然科学基金项目(21076202
21376231)资助~~
作者简介
吕恒花（1992-），女，硕士生。E-mail：ouclvhenghua@163.com;通讯作者：E-mail:wulianying@ouc.edu.cn
