Intensification of Laminar Heat Transfer in Stabilized Air Flow in a Narrow Channel with Single-Row Sparse Inclined Oval-Trench Dimples on the Wall as the Reynolds Number Increases from 50 to 1500

A numerical simulation is carried out to study the intensification of laminar heat transfer in an air flow along a stabilized hydrodynamic section in a narrow channel of height 1 and width 6, with a sparse array of oval-trench dimples (OTDs) inclined at 45°, having a depth of 0.25 and a length of 4.5, arranged at a pitch of 4 on a heated isothermal wall with the Reynolds number varying from 50 to 1500. As Re increases, a swirling flow is formed and intensified in the inclined dimple with a gradual increase in the static pressure difference between the flow’s braking zones on the windward slope of the inlet section and the negative pressure at the point of the generation of a tornado-like vortex. At high Re numbers, spiral vortices emerge from the rear of the dimple, with the flow and heat transfer gradients increasing on the leeward slope. At Re = 1500, the swirling flow’s velocity reaches 70%, the longitudinal velocity in the core of the channel flow is 2.15 times higher than the average mass velocity, and the relative heat transfer approaches 2 with relative hydraulic losses of 1.44.