Vortex Convective Heat-transfer Enhancement with a Single Inclined Groove’s Depth Increase on a Flat Plate during Turbulent Airflow

In the present study, the RANS-SST approach was employed for numerical modeling and gradient heatmetry, enabling the examination of convective heat transfer during turbulent airflow around a 45-angled groove on an isothermal steam-heated section of a flat plate under the following conditions: a Reynolds number (Re) of 3 × 104 with the groove’s depth varying from 0.05 to 0.35 relative to the groove’s width. Through experimental and numerical analysis, a twofold increase in relative heat flux was established at the inlet region of the bottom groove in the central longitudinal section within the high-intensity recirculation flow zone. Our investigation revealed the increase in separated flow, recirculation, downward, upward, and swirling flows within the groove with increased depth. In particular, a critical relative depth of 0.2 was identified, marking the onset of abnormal enhancement of separated flow and heat transfer in the inclined groove’s entrance on the heated plate. As the swirling flow progressed along the groove, its velocity escalated, accompanied by a considerable thinning of the near-wall layer in the entrance segment. In contrast, the near-wall layer thickened, especially toward the groove’s center and outlet.