Numerical Study of Eccentric Jet Impingement Cooling on a Heated Cylindrical Surface

Abstract

This article presents a comprehensive numerical analysis of the effects of cooling a cylinder using an eccentric slot jet impingement cooling (SJIC). The study focuses on examining the thermal and fluid behavior when the slot jet is offcenter, during impingement cooling. Several turbulence models from the k–ε and k–ω families were compared by evaluating the local Nusselt number profiles at different locations around the cylinder, and these results were compared to experimental data. The findings indicate that the SST k–ω model outperforms the other turbulence models in estimating the Nusselt number in the stagnation region, while the standard k–ω model shows improved performance elsewhere on the cylinder. Furthermore, this study reveals a decrease in the maximum local Nusselt number and a shift in the direction of the nozzle displacement. The presence of swirling/recirculating fluid at the trailing end of the cylinder enhances heat transfer near the back end of the cylinder. The separation and the reattachment of the fluid stream differ depending on the Reynolds number, with low Reynolds numbers resulting in reattachment on the side of the slot jet and higher Reynolds numbers leading to reattachment in the opposite direction. Additionally, the length of the recirculation and swirling zones increases as the nozzle-to-cylinder spacing (H/S) increases. However, as the eccentricity (E/S) increases, the size of the swirl circulation zones decreases and completely vanishes for E/S = 4. This study provides valuable insights for optimal cooling design.