HEAT TRANSFER ANALYSIS OF AN IMPINGING SLOT JET ON A CONCAVE SURFACE

Numerical laminar flow simulations of an impinging slot jet on concave surfaces were performed to investigate the heat transfer behaviour on those surfaces. This was accomplished for six different geometry configurations and three types of fluids. The fluids used are air, water and a nanofluid composed of water with a concentration of 6% Al2O3 nanoparticles. The type of fluid used has an important effect on the heat transfer of the concave surface. Furthermore, certain geometric configurations produce an oscillation of the jet inside the impact zone at the Reynolds number investigated (e.g. Re-b = 1400 and 6666 based on the width b of the jet). The presence of this phenomenon depends on the concave surface diameter to jet width ratio ( D/b) and the impact height to jet width ratio (H/b) used. A uniform Nusselt number distribution was obtained when the oscillation of the jet was present compared with the common Gaussian distribution shape usually reported for this type of configuration. Using different fluids and controlling the sweeping of the jet along the concave surface can efficiently increase the heat transfer properties for this type of geometry. Results show that the total heat transfer along the concave surface can be increased up to 416% for water compared with air and 38% for the nanofluid compared to water on average for the six geometries studied at Re-b = 1400.