Simulation on the effect of impinging distance for the aerodynamic and heat transfer characteristics of sweeping jet and film composite cooling

Abstract

The influence of different impinging distances for sweeping jet cooling is investigated by employing the conjugate heat transfer method in a blade leading edge model with film holes. Three impinging distances (P/D = 3, 4, 5) are discussed and compared with the blowing ratio varying from 1.05 to 4.11. In addition, the SST k-ω turbulence model is validated by comparing the sweeping frequency and spanwise-averaged Nusselt number. Results indicate that the three impinging distance schemes obtain similar flow structures under identical blowing ratios. The total pressure loss coefficient is insensitive to the impinging distance and increases with the increasing blowing ratio. The Nusselt number and overall cooling effectiveness (OCE) are enhanced in response to the increased blowing ratio for all cooling schemes. A smaller impinging distance obtains a more considerable internal impingement cooling effectiveness, but the overall cooling effectiveness under each impinging distance is basically the same. Therefore, the results show that the sweeping jet and film composite cooling (SJF) can be applied to actual blades without considering the impinging distance.