Study on the Ablation Phenomenon of High-Strength Refractory Metal for Rocket Nozzle Throat

Abstract

Ablation experiments for pure tungsten and tungsten composites, W-HfC and W-ZrC, with addition of Computational Fluid Dynamics were performed to study the ablation characteristics and ablation resistance of the materials. Ablation characteristics of pure tungsten with respect to enthalpy and stagnation pressure were studied through series of ablation experiments. The amount of recession caused by ablation increased with respect to enthalpy and the mass lost due to ablation was found to be linearly proportional to the stagnation pressure. In addition to the experiment, ablation phenomenon analysis framework was established. Tungsten ablation was analyzed for the mentioned experiments to obtain results, such as maximum surface temperature, interior temperature distribution of the tungsten specimen, etc., which were not possible with the experiments. Moreover, to overcome the weakness of tungsten

vulnerable to oxidation and ablation in high-temperature conditions, W-ZrC and W-HfC composites were manufactured using three different methods. Ablation experiments and micro-structural analyses were carried out to study the ablation characteristics and ablation resistance of W-ZrC and W-HfC with respect to manufacturing method and volume fraction of ZrC and HfC. Methods to increase tungsten composites ablation resistance were suggested with the basis of results of the experiments, CFD analyses, and micro-structural analyses. The suggested methods were to produce composites with small particles and to form ZrOx, HfOx layer on the surface.