Effect of nozzle configurations and jet orientations on thermal performance of jet impingement on convex surface

The present study analyze the thermal behaviour of multiple jets impinging on a convex heated surface for two different nozzle geometries (circular and elliptical) and its orientations. Tests are performed with 5 different nozzles at different values of non-dimensional nozzle to surface distance (z/d = 2-10) and Reynolds number (5000-28000). At smaller value of non-dimensional nozzle to plate distance, a distinct pattern of temperature variation is observed that depend on the nozzle shape and orientation, and this pattern diminishes as surface to nozzle distance increases. In the farthest region, elliptical nozzle is found to improve the uniformity (up to 60 %) in Nu variation compared to the circular jets even at the largest surface to nozzle distance. The overall heat transfer is found to increase up to 18 % and the uniformity is found to enhance up to 60 %) for N-2 and N-3 nozzles. An improvement in the thermal performance is observed in the elliptical nozzle in the fountain and impingement zones. The non-uniformity in the Nu behaviour is found to increase with the increase in Reynolds number.