화학공학소재연구정보센터
International Journal of Heat and Mass Transfer, Vol.42, No.15, 2921-2933, 1999
Pulsed radial jet reattachment nozzle
Steady periodic surface pressure distributions have been obtained for a mechanically pulsed radial jet reattachment (PRJR) nozzle. Local time-averaged and average Nusselt numbers have been obtained for air flow exiting a PRJR nozzle and impinging on a flat plate. The Nusselt numbers were obtained as ii function of the following nondimensional nozzle parameters: Reynolds number, nozzle to plate spacing, exit angle, Strouhal number (pulsation frequency), exit gap spacing, and pulsation amplitude. The nozzle exit gap is cyclically varied for a PRJR nozzle, causing pulsations in the flow field that alter the convective coefficients and surface pressure distribution when compared to flow exiting an RJR nozzle under similar conditions. It was shown that the Nusselt number is a strong function of the Reynolds number, exit angle, and the combined effects of nozzle height, pulsation amplitude, and pulsation frequency.