Advancements in analyzing air-side heat transfer coefficient on the individual tube rows in finned heat exchangers: Comparative study of three CFD methods

This paper describes the heat transfer performance of plate-fin-tube heat exchangers (PFTHE) using computational fluid dynamics (CFD) simulation. Air-side Nusselt number correlations obtained from CFD simulations are compared to existing empirical correlations found in the literature. The geometries and boundary conditions are presented and compared with previous studies. The results indicate relative differences in mean Nusselt numbers between CFD-based methods and empirical correlations for different Reynolds numbers. Several factors contributing to these differences are discussed, including thermal resistance issues and assumptions about fluid-side heat transfer coefficients. The proposed CFD-based methods provide insight into the heat transfer mechanisms on individual tube rows, with acceptable differences compared to experimental correlations. Comparison of these methods shows consistent results with relatively small average relative errors, indicating the effectiveness of CFD simulations in predicting the heat transfer performance of PFTHE. Moreover, the average relative errors between individual methods range from 5.1 % to 6.9 %, with some individual errors ranging from 0.1 % to even 17.1 %. These results demonstrate the potential of CFD simulations to accurately predict heat transfer characteristics in complex heat exchanger systems.