Study on Heat Transfer during Rectangular Slot Air Jet Impingement on Curved Surfaces

摘要

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 on heat transfer during rectangular slot air jet impingement on curved surfaces of different radius of curvature. The average Nusselt Number on the impingement surface is presented for different target plates of R/L ratio 0.5, 0.725, 1.3 and flat surface manufactured from aluminum plate of thickness 3 mm. Reynolds number based on hydraulic diameter (D_h) between 1589.5 to 5881.6 and four values of nozzle-to-impingement surface distances from 10 to 16 times nozzle width are considered. The heat transfer results of this investigation indicates that the shape of the target surfaces and nozzle geometry have significant effect on the heat transfer distribution. The results showed that average Nusselt number has significant dependency on the wall-to-jet-spacing. For small wall-to-jet spacing the Nu_(avg) increases and for larger wall-to-jet-spacing the Nu_(avg) decreases and found to be unaffected for higher H/W ratio. The closeness of the target plate from the jet exit and surface curvature of the target plate has an impact on the average heat transfer coefficient.