Abstract
Nuclear thermal propulsion is an effective propulsion technology that can meet the needs of deep space exploration. The nozzle of the nuclear thermal propulsion system endures high-temperature and high heat flux environment, while supersonic film cooling is an important cooling method to provide thermal protection. The present study numerically investigated the effect of the blowing ratio and the shock wave on supersonic film cooling with discrete holes. The results show that when the blowing ratio is large, a strong kidney vortex is formed and the high-temperature mainstream enters the cooling layer. Therefore, the film cooling effectiveness at the upstream region near the hole decreases rapidly at a large blowing ratio. For the middle and downstream regions, the increase of blowing ratio gives a larger coolant mass flow rate and thereby improves film cooling effectiveness. In general, film cooling effectiveness decreases with shock wave impingement. For a strong shock wave, the cooling stream shows strong lateral diffusion after the shock wave impinging region. As a result, the lateral average film cooling effectiveness increases first and then decreases. This phenomenon is more obvious at a larger blowing ratio.
