Investigation of air inlet angle influence on air-side heat transfer performance of finned oval tube heat exchanger

doi:10.11949/0438-1157.20190527

Abstract

Abstract:

Heat transfer performance of a finned oval tube heat exchanger with various air inlet angles (30°,45°,60° and 90°, respectively) were experimentally investigated in this study. Experimental results showed that heat transfer performance decreased with decreasing air inlet angle, and the experimental correlation of the air-side Nusselt number was obtained in the studied range of Reynolds numbers and air inlet angles. Heat transfer performance of various air inlet angles was simulated by using CFD software Ansys Fluent, and the simulated results agreed well with the experimental results. The numerical results indicated that with the decrease of air inlet angle, the uniformity of air velocity distribution in z-direction became worse, therefore, the comprehensive heat transfer performance was worse than that of the case with uniform flow distribution.

Key words: finned oval tube heat exchanger, air inlet angle, heat transfer, experimental validation, CFD

摘要：

对两排椭圆管翅式换热器实验元件在不同进风角度下（30°、45°、60°和90°）的换热性能进行了实验研究，结果表明，在测试的迎风速度范围内随着进风角度的减小换热器换热性能减弱，并给出了测试工况范围内的换热性能经验关联式；对不同进风角度下空气侧换热性能进行了数值计算，与实验结果进行对比，符合良好；最后对不同进风角度下换热器内不同通道内空气平均速度的分布进行了研究，解释了换热性能差异的原因，为相应的工程应用提供理论参考。

关键词: 椭圆管翅式换热器, 进风角度, 传热, 实验验证, CFD

CLC Number:

TK 124

Linghong TANG, Xueping DU, Min ZENG. Investigation of air inlet angle influence on air-side heat transfer performance of finned oval tube heat exchanger[J]. CIESC Journal, 2019, 70(S2): 138-145.

唐凌虹, 杜雪平, 曾敏. 进风角度对椭圆管翅式换热器传热性能影响[J]. 化工学报, 2019, 70(S2): 138-145.

Figures/Tables 14

Fig.1 Schematic diagram of experimental system

Fig.2 Test heat exchanger unit

Fig.3 Four different air inlet angles

Fig.4 2-row finned oval-tube heat exchanger

Table 1 Geometric dimension of heat exchanger

参数	数值
横向管间距P_t/mm	26.7
纵向管间距P_l/mm	60
管壁厚度δ_t/mm	1.5
翅片厚度δ_f/mm	0.35
翅片间距F_s/mm	2.5
椭圆管短轴2b/mm	14
椭圆管长轴2a/mm	36
迎风面宽度W/mm	600
迎风面高度H/mm	320

Fig.5 Heat transfer coefficient comparisons with different air inlet angles

Fig.6 Nu comparisons with different air inlet angles

Fig.7 Nu comparison of experimental data and numerical data

Fig.8 Schematic diagram of physical model

Fig.9 Nu comparison of experimental data and numerical data for air inlet angle of 45°

Fig.10 Nu comparison for various air inlet angles

Fig.11 Velocity distribution in y-direction for various inlet angles

Fig.12 Velocity distribution in z-direction at central position of the first row for various inlet angles

Fig.13 Velocity distribution in z-direction at central position of the second row for various inlet angles

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