Comprehensive analysis of thermo-hydraulic performance for finless flat tube heat exchangers: a modeling and experimental approach

Ultra-thin finless flat tube heat exchangers are investigated through combined numerical and experimental methods. A parametric numerical analysis is conducted to examine the effects of tube configuration, inlet air velocity, and tube spacing on air-side heat transfer and pressure drop. Four heat exchanger configurations are tested under various inlet air velocities and water-side flow rates. Compared with the conventional fin and tube heat exchanger, the finless flat tube heat exchangers yield lower friction factors and up to 6% lower pressure drop. When Re exceeds 200, they also exhibit higher j/f^1/3 values, indicating better overall thermo-hydraulic performance.