Numerical study on heat transfer performance of bionic microchannel heat exchangers
Hu, Jingdi (2026)
Kandidaatintyö
2026
School of Energy Systems, Energiatekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2026052653775
https://urn.fi/URN:NBN:fi-fe2026052653775
Tiivistelmä
This thesis explores the thermal-hydraulic performance of a smooth baseline microchannel and four ribbed microchannel configurations, including fish-shaped ribs, V-shaped ribs, tree-like Y-shaped branching ribs, and rectangular ribs, through three-dimensional CFD simulations in ANSYS Fluent. All cases were analysed under identical boundary conditions, using water as the working fluid, a constant bottom-wall heat flux of 1.0 × 10^5 W/m², an inlet temperature of 300 K, and inlet velocities ranging from 0.15 m/s to 0.75 m/s.
The influence of rib geometry on flow disturbance, wall temperature distribution, pressure drop, and overall cooling performance was evaluated using pressure drop, fluid temperature rise, average wall temperature, maximum wall temperature, and derived thermal resistance. The results show that all ribbed configurations improve convective heat transfer compared with the smooth baseline channel, although they also lead to increased hydraulic resistance. Among the cases considered, the V-shaped rib configuration shows the strongest overall thermal performance, with the lowest average wall temperature and thermal resistance over the investigated velocity range. The tree-like Y-shaped branching rib configuration provides the best balance between thermal enhancement and pressure-drop penalty, while the fish-shaped rib configuration results in the smallest hydraulic penalty among the enhanced cases. The rectangular rib configuration also improves heat transfer, but its overall thermo-hydraulic performance remains weaker than that of the V-shaped and Y-shaped rib configurations.
The results indicate that internal rib geometry has a significant effect on the thermal-hydraulic behaviour of microchannels and that suitably designed bio-inspired structures can effectively enhance heat transfer performance. This study provides useful guidance for the design and optimisation of compact microchannel heat exchangers for thermal management applications.
The influence of rib geometry on flow disturbance, wall temperature distribution, pressure drop, and overall cooling performance was evaluated using pressure drop, fluid temperature rise, average wall temperature, maximum wall temperature, and derived thermal resistance. The results show that all ribbed configurations improve convective heat transfer compared with the smooth baseline channel, although they also lead to increased hydraulic resistance. Among the cases considered, the V-shaped rib configuration shows the strongest overall thermal performance, with the lowest average wall temperature and thermal resistance over the investigated velocity range. The tree-like Y-shaped branching rib configuration provides the best balance between thermal enhancement and pressure-drop penalty, while the fish-shaped rib configuration results in the smallest hydraulic penalty among the enhanced cases. The rectangular rib configuration also improves heat transfer, but its overall thermo-hydraulic performance remains weaker than that of the V-shaped and Y-shaped rib configurations.
The results indicate that internal rib geometry has a significant effect on the thermal-hydraulic behaviour of microchannels and that suitably designed bio-inspired structures can effectively enhance heat transfer performance. This study provides useful guidance for the design and optimisation of compact microchannel heat exchangers for thermal management applications.