摘要
为了分析换热管几何参数对扭曲椭圆管换热器管程和壳程的传热与压降性能以及场协同关系的影响,今运用Fluent 6.3.26对不同几何参数的扭曲椭圆管换热器的管内和管外对流传热进行了数值模拟,并编写UDF程序计算温度场与速度场的夹角,即场协同角。结果表明:Realizable k-ε模型相对更好地模拟出扭曲椭圆管换热器管内和管外的流场和温度场,努赛尔数Nu以及摩擦系数f与实验结果的差别都在5%以内。在扭曲椭圆管换热器的管程和壳程,Nu和f都随着扭曲椭圆管长短轴比的增大而增大,随着扭矩的减小而增大。基于场协同理论分析,协同角随Re的变化不大,但不同几何参数的扭曲椭圆管管内和管外的协同角都存在差异,二次流的出现优化了速度场以及温度场分布,减小了速度场以及温度梯度场之间的夹角,实现强化传热。
In order to analyze the effects of geometrical parameters on heat transfer, pressure drop performance and field synergy of both tube side and shell side in twisted oval tube heat exchanger, as well as the convective heat transfer of twisted oval tube heat exchangers with different geometrical parameters, were simulated with Fluent 6.3.26. A user defined function （UDF） was also designed to calculate the included angle between the temperature field and the velocity field, which is referred as field synergy angle. The results show that： （1） Realizable k-ε model is relatively better than Standard k-ε model and RNG k-ε model for the fields simulation of both sides of the tubes in the twisted oval tube heat exchanger. The difference of calculated Nu and f with experimental results are both less than 5%. （2） The heat transfer factor and friction factor are in proportion to axial ratio of the oval tube and in inverse proportion to torque both on tube side and shell side in twisted oval tube heat exchanger. （3） Based on field synergy principle, synergy angle does not change significantly with Re. However, the twisted tubes with different geometrical parameters have different synergy angle on both sides of the tube. The secondary flow optimizes both temperature and velocity distribution, thus the angle between the velocity and temperature field is reduced and heat transfer is enhanced.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2015年第1期64-71,共8页
Journal of Chemical Engineering of Chinese Universities
基金
2013HK100103佛山市院市合作项目(科技创新)"
"201312NO82013年"扬帆计划"引进创新创业团队""三维变空间高效中冷器的技术开发产学研(含院地合作)""高效节能平行流制冷机组13C2614404587科技型中小企业创新基金
关键词
扭曲椭圆管
数值模拟
场协同分析
协同角
强化传热
twisted oval tubes
numerical simulation
field synergy analysis
synergy angle
heat transfer enhancement
