Local heat transfer characteristics of synthetic air jet impinging on a smooth convex surface

Abstract

The local heat transfer characteristic of synthetic air jet impinging on convex surface is studied experimentally. The heat flux on the convex surface is maintained constant. The experiment is carried out for different actuator frequency (f = 100 Hz–300 Hz), jet to plate distance (z/d = 1 to 8) keeping the orifice diameter constant. The local heat transfer characteristic of synthetic air jet on the convex surface is obtained by IR thermal imager using thin foil technique. Local heat transfer characteristics is studied in terms of local Nusselt number along the axial (x/d at r = 0) and radial direction (r/d at x = 0) of convex surface. The obtained result shows that the local heat transfer is strongly influenced by actuator frequency and jet to plate distance. The actuator frequency (f = 200 Hz) and lower jet to plate distance (z/d = 2) is observed effective at all jet to plate distance and actuator frequency. The correlation of maximum local Nusselt number in terms of Reynolds number is obtained with the maximum deviation of 18%. The maximum uncertainty in measurement of average Nusselt number is observed less than ±6%.