Effect of rotating speed on heat/mass transfer of jet impingement in cone-type cavities

Heat/Mass transfer of circular jet impinging in cone-type cavities with one end open to the ambient air was investigated via naphthalene sublimation technique. Three types of cavities were investigated cylindrical, converging-type and diverging-type. A round nozzle was placed at the center of the cavities. The round nozzle was stationary, while the cavity might rotate around its axis. Experimental measurements were conducted for both the stationary and the rotating cases. The emphasis of this study was focused on the effect of the rotating speed on the heat/mass transfer. It was found that flow pattern transition (from laminar to turbulent) seemed to occur within the jet Reynolds number range from 7×10³ to 1×10⁴. In the range of the rotating speed tested (from 240 to 1400 rpm), the effect of rotation on heat/mass transfer was negligible for the turbulent flow regime, while in the laminar flow regime the rotation might have significant to moderate effect on the mass transfer, ranging from 50% to about 10% enhancement.