Numerical Simulation on Internal Flow and Heat Transfer of Sweeping Jet and Film Composite Cooling on a Flat Plate

Abstract

Numerical simulation has been performed to investigate the internal heat transfer characteristics of sweeping jet and film cooling together with the representative flow characteristics on a flat plate. SST k_-_ω _turbulence model was employed for a fluidic oscillator with twenty cylindrical film holes at four different blowing ratios and four different inclination angles. Time-resolved flow fields and time-averaged heat transfer analysis considering thermal convection and conduction by coupling of fluid and solid domains were presented. Results indicate that the total pressure loss coefficient of sweeping jet is larger than those of normal jet, especially when blowing ratio is relatively higher. The Nu number monotonously increases with the increase of blowing ratio and decrease of inclination angle in all different cases, but the Nu number distribution on the impingement wall is insensitive to the inclination angle of film holes. Compared to normal jet, sweeping jet has a more spatially uniform heat removal rate, but the area-averaged Nu number is higher only when blowing ratio is 4. Therefore, sweeping jet and film composite cooling is desirable to make the distribution of flat wall heat transfer more uniform, but the impinge distance of fluidic oscillator should be further optimized to improve the impingement cooling effectiveness and the total pressure loss coefficient.