Computational study of nozzle configuration of jet impingement heat transfer on concave surface

Jet impingement has been actively utilised in many applications for cooling and drying as it gives high heat transfer coefficient. This technique has proven highly effective in eliminating excessive thermal loads, such as the leading edges of turbine blades and the outer walls of combustors. This study investigates turbulent jet impingement cooling on a concave surface with a focus on how jet to surface spacing and Reynolds number govern hydrodynamics and heat transfer. A validated Reynolds averaged Navier–Stokes model with constant wall heat flux and a mesh independent solution was used to map area averaged Nusselt number and turbulent kinetic energy near impingement. The findings show strong dependence on the small jet-to-surface distance, H/B (0.50). An increasing nozzle diameter from 5 to 15 mm increases the Nusselt number from 86.58 to 170.77 (97% increase) and turbulent kinetic energy from 82.28 to 1093.91 m²·s⁻². H/B is the dominant control parameter at fixed diameter. The Nusselt number decreases from 170.77 at H/B = 0.50 to 71.69 at H/B = 8.00 for 15 mm nozzle diameter which is a 58% reduction. Increasing Reynolds number strengthens turbulence at the impingement region, improves mixing, enlarges the effective cooling area, and aligns with higher Nusselt number. These findings indicate a preference for small to moderate jet-to-surface distance with sufficiently high Reynolds numbers for concave targets and support energy efficient thermal management in advanced industrial systems.