STUDY ON HEAT TRANSFER AND FLOW VISUALIZATION OF JET INTERACTION DURING RECTANGULAR SLOT AIR JET IMPINGEMENT ON CONCAVE SURFACES
An appropriate configuration of cooling jet and target plate geometry helps in optimizing an efficient heat-transfer design. This part of research investigation is an experimental study carried out over wide range of parameters: the Reynolds number Re from 1589.5 to 5881.6, the relative nozzle-to-surface distance H/W from 20 to 28. The Average Nusselt Number on the impingement surface are presented for different target plates of R/L ratio 0.5, 0.75, 1.0 and flat surface manufactured from aluminum plate of thickness 3 mm. The experimental results of this investigation indicate that the shape of the target surfaces and nozzle geometry have significant effect on performance and characteristics and characteristics of jet impingement heat transfer. The results showed that a significant dependency in heat transfer enhancement by the nozzle-to-surface distance. For small nozzlel-to-surface spacing the Nuavg increases and for larger nozzle-to-surface spacing Nuavg decreases and found to be unaffected for higher H/W ratio. The closeness of the target plate from the nozzle jet exit and surface curvature of the target plate has an impact on the average heat transfer coefficient.