Simulation of flow structure and heat transfer of sweeping jet and film composite cooling on a flat plate

Abstract

Numerical simulation was performed to investigate the heat transfer characteristics of sweeping jet and film cooling along with the representative flow characteristics on a flat plate. The SST k-ω turbulence model was employed for a fluidic oscillator with 20 cylindrical film holes at four different nozzle Reynolds numbers and four different inclination angles. Time-resolved flow field and time-averaged heat transfer analyses considering the thermal convection and conduction by the coupling of fluid and solid domains are presented. The results show that the total pressure loss coefficient of the sweeping jet is larger than that of the normal jet, especially when the nozzle Reynolds numbers are relatively higher. In all cases, the Nusselt number and overall cooling effectiveness monotonically increased with the increase in the nozzle Reynolds numbers and decrease in inclination angle. However, the Nusselt number distribution on the impinging surface is insensitive to the inclination angle of the film holes. Compared with the normal jet and film composite cooling, sweeping jet and film composite cooling (SJF) has a more spatially uniform heat removal rate, and the area-averaged Nusselt number and overall cooling effectiveness are higher. Therefore, the SJF is preferred to improve the utilization rate of the coolant and to make the distribution of the flat wall heat transfer more uniform. However, the impinging distance of the fluidic oscillator should be further optimized to improve the impingement cooling effectiveness and the total pressure loss coefficient.