A numerical study on air-side heat transfer enhancement and outlet temperature uniformity improvement of fin-tube heat exchanger

TY - JOUR

T1 - A numerical study on air-side heat transfer enhancement and outlet temperature uniformity improvement of fin-tube heat exchanger

AU - Li, Li

AU - Gao, Haojian

AU - Lin, Xuemei

AU - Zheng, Keqing

AU - Chen, Yuezeng

AU - Qu, Zhiguo

N1 - Publisher Copyright: © 2026 Elsevier Inc.

PY - 2026/9

Y1 - 2026/9

N2 - Many industrial processes have strict temperature uniformity requirements. This work aims to enhance air-side heat transfer performance and improve outlet temperature uniformity of fin-tube heat exchanger simultaneously. Non-uniform fin design and additional mixing tubes are proposed as potential strategies and their feasibilities are validated via numerical investigations. Differences in the underlying mechanisms of the proposed strategies are analyzed based on the comparisons of flow patterns and temperature distributions. The enhanced heat transfer performance of non-uniform fin design is attributed to the increased heat transfer area and decreased airflow velocity in pre-tube section and the accelerated airflow in post-tube section. Meanwhile, the additional mixing tubes could reduce the wake region of the adjacent copper tube in front of the mixing tube and increase the airflow velocity around the adjacent copper tube after the mixing tube. In the heat exchanger design, these two strategies can be utilized together to obtain a better heat transfer effect via combined effect of these two mechanisms. Further, effects of two key parameters, including outer diameter of the mixing tube and width of the first sub-section in pre-tube section, are examined. Increased outer diameter of mixing tube and decreased first sub-section width in pre-tube section are conducive to heat transfer performance of fin-tube heat exchanger. Considering the balance between heat transfer and flow resistance, the suggested mixing tube diameter and first sub-section width in pre-tube section within the tested cases are 4 mm and 1 mm, respectively.

AB - Many industrial processes have strict temperature uniformity requirements. This work aims to enhance air-side heat transfer performance and improve outlet temperature uniformity of fin-tube heat exchanger simultaneously. Non-uniform fin design and additional mixing tubes are proposed as potential strategies and their feasibilities are validated via numerical investigations. Differences in the underlying mechanisms of the proposed strategies are analyzed based on the comparisons of flow patterns and temperature distributions. The enhanced heat transfer performance of non-uniform fin design is attributed to the increased heat transfer area and decreased airflow velocity in pre-tube section and the accelerated airflow in post-tube section. Meanwhile, the additional mixing tubes could reduce the wake region of the adjacent copper tube in front of the mixing tube and increase the airflow velocity around the adjacent copper tube after the mixing tube. In the heat exchanger design, these two strategies can be utilized together to obtain a better heat transfer effect via combined effect of these two mechanisms. Further, effects of two key parameters, including outer diameter of the mixing tube and width of the first sub-section in pre-tube section, are examined. Increased outer diameter of mixing tube and decreased first sub-section width in pre-tube section are conducive to heat transfer performance of fin-tube heat exchanger. Considering the balance between heat transfer and flow resistance, the suggested mixing tube diameter and first sub-section width in pre-tube section within the tested cases are 4 mm and 1 mm, respectively.

KW - Fin-tube heat exchanger

KW - Heat transfer performance

KW - Temperature uniformity

UR - https://www.scopus.com/pages/publications/105048498366

U2 - 10.1016/j.ijheatfluidflow.2026.110642

DO - 10.1016/j.ijheatfluidflow.2026.110642

M3 - Article

AN - SCOPUS:105048498366

SN - 0142-727X

VL - 121

JO - International Journal of Heat and Fluid Flow

JF - International Journal of Heat and Fluid Flow

M1 - 110642

ER -