Effects of elliptical pin-fins on heat transfer characteristics of a single impinging jet on a concave surface

The effect of elliptical pin-fins on heat transfer enhancement from a concave surface has been investigated. The experiments have been performed for a single jet impinging on a concave surface under constant heat flux. The elliptical pin-fins with 8.0 mm thickness were placed in a circular arrangement on a concave surface with a constant curvature ratio. In addition, numerical simulations were performed to study the effects of jet diameter and curvature ratio on the flow field and heat transfer in a concave surface with elliptical pin-fins. The numerical results obtained by SST-k-m turbulence model agree well with the experimental data. The experimental and numerical results of the present study reveal that the elliptical pin-fins can effectively enhance the heat transfer rate from the concave surface. Comparisons of the results confirm that applying the pin-fins are more efficient at higher relative curvature, which corresponds to the concave surfaces with lower diameter. Also for a constant relative curvature, the pin-fins show better performance in higher jet Reynolds numbers. It has been found that the concave surface with pin-fins provides more area-averaged Nusselt number in comparison with the smooth concave surface by 51%, 53% and 59% for the jet Reynolds number of 23,000, 35,000 and 55,000 respectively. (C) 2020 Elsevier Ltd. All rights reserved.