Effect of height of winglet vortex generators on thermal hydrodynamic performance of tube bank fin heat exchanger

doi:10.11949/j.issn.0438-1157.20170492

Abstract

Abstract:

The delta winglet vortex generators can significantly enhance the heat transfer in tube bank fin heat exchangers with a moderate pressure loss penalty. The height of vortex generator has a great influence on the fluid flow and heat transfer of heat exchanger. The effects of height of delta winglet vortex generators on intensity of secondary flow and heat transfer performance of a circular tube bank fin heat exchanger were investigated numerically. Three different heights of vortex generators 1.5,1.75 and 2.0 mm were studied. The results show that under the same Reynolds number,the values of Nusselt number,friction factor and longitudinal vortex intensity all increase with increasing the height of vortex generators. There is one-to-one correlation between the volume average non-dimensional intensity of secondary flow and Nusselt number for all the cases that studied,but there is no such correlation with the friction factor. To screen the optimal height of vortex generators,an appropriate evaluation criterion JF is used and we obtain that the comprehensive heat transfer performance is best if the height of vortex generators is 1.75 mm for the studied cases.

Key words: numerical simulation, secondary flow, height of vortex generator, convection, heat transfer

摘要：

采用数值模拟方法分析了三角形小翼式涡产生器翼高分别为1.5、1.75和2.0 mm时对圆管管翅式换热器空气侧传热及纵向涡强度的影响。结果表明：在相同Re下，随着翼高的增加，Nu、阻力系数 f 以及量纲1二次流强度Se_m都增大；所研究各模型的Se_m与Nu呈唯一对应关系，并且获得了Se_m与Nu的定量关系；以强化传热因子JF作为评价准则，得出翼高为1.75 mm时能够使换热器获得较优的综合强化传热效果。

关键词: 数值模拟, 二次流, 翼高, 对流, 传热

CLC Number:

TK124

HU Wanling, WANG Liangbi. Effect of height of winglet vortex generators on thermal hydrodynamic performance of tube bank fin heat exchanger[J]. CIESC Journal, 2017, 68(S1): 169-177.

胡万玲, 王良璧. 涡产生器翼高对管翅式换热器流动与传热的影响[J]. 化工学报, 2017, 68(S1): 169-177.

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