CAJ | 학술논문

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： Realizablek-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。
위료분석환열관궤하삼수대뉴곡타원관환열기관정화각정적전열여압강성능이급장협동관계적영향，금운용Fluent 6.3.26대불동궤하삼수적뉴곡타원관환열기적관내화관외대류전열진행료수치모의，병편사UDF정서계산온도장여속도장적협각，즉장협동각。결과표명： Realizablek-ε모형상대경호지모의출뉴곡타원관환열기관내화관외적류장화온도장，노새이수 Nu 이급마찰계수 f 여실험결과적차별도재5%이내。재뉴곡타원관환열기적관정화각정， Nu화f도수착뉴곡타원관장단축비적증대이증대，수착뉴구적감소이증대。기우장협동이론분석，협동각수Re적변화불대，단불동궤하삼수적뉴곡타원관관내화관외적협동각도존재차이，이차류적출현우화료속도장이급온도장분포，감소료속도장이급온도제도장지간적협각，실현강화전열。
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) Realizablek-εmodel is relatively better than Standard k-εmodel and RNG k-εmodel for the fields simulation of both sides of the tubes in the twisted oval tube heat exchanger. The difference of calculatedNu andf 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 withRe. 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.