ISSN: 2949-401X

Selezneva M. D., Knyazev S. A., Klyus A. A., Seroshtanov V. V.

Abstract. An experiment has been conducted to investigate convective heat transfer during turbulent air-flow around a heated plate with an inclined oval-trench dimple (OTD). “Medium” (L = 3 – the length of the cylindrical insert is related to the dimple’s width) and “long” (L = 5) OTDs of moderate depth at a Reynolds number of 3∙104 were studied. The inclination angle of the dimple to the free-stream flow velocity vector varied from 0 (longitudinal flowing) to 90° (transverse flowing). The heat flux was measured by using gradient heat flux sensors made of monocrystalline bismuth. The experiments were carried out in the wind tunnel of the REC “Energy Thermophysics” of Peter the Great St. Petersburg Polytechnic University. The oval-trench dimple inclination angle, at which heat transfer enhancemnt was observed exceeding the parameters of spherical or oval dimples, was determined. It has been experimentally confirmed that high-speed return and secondary swirling flows occurring in an inclined oval-trench dimple lead to an anomalous heat transfer enhancement in the inlet part of the oval-trench dimple.

Keywords: inclined oval-trench dimple, separated flow, anomalous heat transfer enhancemnt, gradient heatmetry, local Nusselt number

For citation: Selezneva M. D., Knyazev S. A., Klyus A. A., Seroshtanov V. V. Heat transfer enhancement in a single oval-trench dimple on a plate when changing the angle of inclination from 0 to 90°. Aerospace Engineering and Technology. 2023. Vol. 1, no. 4, pp. 30–41. EDN IRPLRG