Effect of contact resistance on thermo-hydraulic performance for finned tube heat exchanger

Abstract

This study numerically investigates the impact of thermal contact resistance (TCR) at the fin-tube interface on the thermo-hydraulic performance (TPF) of finned-tube heat exchangers (FTHE). Simulations were performed using ANSYS Fluent software at Reynolds numbers of Re = 1000, 2000, 4000, and 8000. The effects of various thermal conductivity (k = 0.5 – 16.27 W/mK) and interface thicknesses (t = 0.1 – 0.8 mm)  of thermal pastes (TP) used to reduce thermal contact resistance on the TPF, average Nusselt number, and flow characteristics were examined in detail. The results indicated that the thermal conductivity coefficient (k) of the TP plays a more dominant role in TPF and heat transfer compared to the TP thickness (t). The TPF showed a strong sensitivity to thermal conductivity up to k = 10 W/mK, after which the enhancement in thermo-hydraulic performance became marginal. Based on a comprehensive evaluation of the results, it was concluded that the interface contact resistance becomes negligible when a TP with a thermal conductivity above 10 W/mK is employed.

Keywords

• Thermal conductivity
• Thermal paste
• Thermal contact resistance
• Heat exchanger

Supporting Institution

Scientific and Technological Research Council of Türkiye

Project Number

125M097

Thanks

The authors express their gratitude to the Scientific and Technological Research Council of Türkiye (TUBITAK ARDEB 1001 Research Programme with project number 125M097) for the financial support it provided.

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