以平直翅片管式换热器为研究对象，利用计算流体力学（CFD）软件进行流动与传热模拟计算。采用正交试验方法确定模型工况，对换热负荷15 kW，设计气温30 ℃，入口风速为1~5 m/s，管壁温度为40~60 ℃，翅片间距为1~5 mm、翅片厚度0.5~4 mm、管纵向间距为0.5~2.5倍外管径，管排数为1~5排的计算工况进行努塞尔数、阻力因子的计算分析。参数敏感性分析结果表明：在1 mm ≤ 翅片间距δ≤5 mm，444≤雷诺数Re ≤3 405时，翅片间距δ是对努塞尔数Nu及阻力因子f影响最大的结构参数。在该范围内提出了由翅片间距与特征长度比值组成的无量纲参数对努塞尔数Nu与阻力因子f的计算关联式。该关联式参数图表明：翅片间距δ越小、雷诺数Re越大，对提高平直翅片努塞尔数、降低阻力因子越有利。

With a flat finned tube heat exchanger as the research object,the flow and heat transfer simulation calculations are carried out by using computational fluid dynamics (CFD) in this paper.The orthogonal test method is used to determine the working conditions,and the Nusselt number and resistance factor are calculated and analyzed for thoses with 15 kW heat exchange load,30 ℃ design temperature,1~5 m/s wind speed at the inlet,40~60 ℃ tube wall temperature,1~5 mm the fin spacing,0.5~4 mm the fin thickness,and the tube spacing in 0.5~2.5 times of the outer diameter along longitudinal direction and 1~5 row number.Then,the sensitivity analyses on Nusselt number and resistance factor are performed.The results show that the fin spacing δ,as a structural parameter,has the greatest influence on the Nusselt number and the resistance factor.Then,the computational correlation of the ratio of fin spacing against feature length on heat transfer and flow resistance is put forward under the condition of 1mm ≤ fin spacing δ≤5 mm and 444≤Reynolds number Re≤3 405.The correlation parameter plot indicates the smaller the fin spacing δ and the larger the Reynolds number Re,the more favorable the heat transfer and resistance to the flat fins.

TK124

四川省教育厅项目(18ZB0560)；西华大学研究生创新基金项目(ycjj2018038)