Finite element analysis of turbulent thermal enhancement in grooved channels with flat- and plus-shaped fins

Abstract This study numerically investigates turbulent convective heat transfer (HT) in a rectangular channel enhanced with fins and grooves using the finite element method and the standard k – ε turbulence model. The novelty lies in the combined evaluation of rectangular, trapezoidal, and triangular grooves by varying the b / c ratio from 1.0 to 0, along with a systematic optimization of plus (+) and flat fin heights. Among six groove configurations, the b / c = 0.75 trapezoidal groove produced the highest temperature increase (Δ T = T out − T inlet ) of 16.54% improvement over the baseline ungrooved channel. Through additional optimization, raising both fin types to 1.50 h was found to provide the optimal thermal performance with an outlet temperature of 51.17°C and a 146.88% improvement in Δ T compared to the baseline. These results highlight the large synergistic effect of groove geometry and fin height optimization, yielding an effective design strategy for enhancing HT in solar heat exchanger devices.