TRANSIENT FLOW AND THERMAL PERFORMANCE OF INTEGRATED DEFLECTOR UNDER PERIODIC SUPERSONIC FLAME IMPINGEMENT

Flow deflector is an effective approach to realize the thermal spreading and flow splitting of high temperature gas from jet impingement. Two integrated deflectors composed of ablation-resistant layer, thermal insulation layer and multifunctional lattice metal layer are designed and prepared. The transient thermal performance of deflectors under periodical supersonic flame impingement is experimentally studied by employing a kerosene flame jet. A verified 3D numerical model is established to analyze the effects of jet distance, horizontal angel and axial angel of deflector on the flow and thermal distribution characteristics. The experimental results show that the temperature variation of impinged surface with impingement periods trends to stable periodic fluctuation after four periods. Compared to carbon aerogel, the phase change material of LiF as the Layer-2 of deflector decreases the whole temperature level of deflector and especially reduces ablation rate of C/SiC plate by about 40%. The numerical simulation finds that the deflector behaves a good fluid deviating capacity towards the given direction (more than 50% gas flow towards the up section). The gas accelerating effect above the impingement position forms a small region with second peak pressure, temperature and heat transfer coefficient. The increase of horizontal angle or the decrease of axial angle enlarges the highest pressure and temperature on impinged surface due to the more uniform gas distributions deviated by deflector.