水平管降膜蒸发器的全三维数值模拟  

Full-three-dimensional Numerical Study of a Horizonal-tube Falling-film Evaporator

作　　者：侯昊[1] 毕勤成[1] 张晓兰[1] 

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049

出　　处：《热能动力工程》2011年第6期694-699,773,共6页Journal of Engineering for Thermal Energy and Power

基　　金：国家重点基础研究发展计划(973计划)基金资助项目(2009CB219805)

摘　　要：针对水平管降膜蒸发器运行和优化设计中存在的流动与传热问题,建立了水平管降膜蒸发器实体的三维分布参数模型,采用数值模拟方法对蒸发器内海水流场、温度场等特性进行了深入研究,获得了相应热力参数分布的详细信息,直观地刻画了蒸发器内部的工作过程以及复杂流动与换热现象。通过数值解与实际值的比较,对模型进行了验证,结果表明:第1、2管程蒸汽进口区总传热系数最大,海水表现出喷淋密度"上高下低"、盐度"上小下大"等细观规律;供入海水流量在280～370 t/h范围内变化对二次蒸汽与加热蒸汽的温差影响较大,而对二次蒸汽产量没有明显的影响,说明海水流量偏离设计值会造成整个海水淡化系统无法正常运行。In the light of the flow and heat transfer problems existing in the operation and optimized design of a horizontal-tube falling-film evaporator,established was an entity three-diemnsional distributed parameter model for the evaporator and studied in depth were such characteristics as seawater flow field and temperature field etc.inside the evaporator by using a numerical simulation method.In this connection,the detailed information showing the distribution of the corresponding thermal parameters was acquired,visually depicting the operation process,complex flow and heat exchange phenomena inside the evaporator.Through a comparison of the numerical solutions with the actual values,the model in quesiton was verified.The calculation results show that the total heat transfer coefficient in the first and second steam inlet zone of the tube side is the biggest and the seawater displays the microscopic law of the sprinkling density in 'the upper portion being higher than that in the lower' and the salinity in the 'upper portion being smaller than that in the lower'.When the seawater supply flow rate changes in a range of 280-370 t/h,it has a big influence on the temperature difference of the secodnary steam and heating steam but has no significant influence on the production capacity of the secondary steam,indicating that the deviation of the seawater flow rate from its design value may result in an abnormal operation of the whole seawater desalination system.

关 键 词：水平管降膜蒸发器 分布参数模型 流动与换热 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理]