In order to enhance energy characteristics of propellants in hybrid rocket motors, aluminum particles are added into the solid fuel. However, these particles may lead to nozzle mechanical erosion, which significantly affects the motor performance. This paper intends to study thermochemical and mechanical erosion mechanism of carbon-based nozzles in hybrid rocket motors with aluminum metallized fuel. A firing test is performed, and 95 % hydrogen peroxide and hydroxyl‑terminated polybutadiene based fuel with aluminum particles are utilized. Experimental results show that many metal particles are ejected from the nozzle, and aluminum oxide deposits heavily on the nozzle inner surface. A method of numerical calculation coupled with two-phase flow, combustion of aluminum metallized fuel, thermochemical ablation reactions, and mechanical erosion is established. The errors of combustion chamber pressure and throat erosion rate between numerical calculation and test results are 0.53 % and 7.76 %, respectively. Simulation results indicate that with the increase of aluminum content, nozzle wall pressure gradually increases, while the mass fraction of HO, CO, OH, and O declines. The nozzle wall temperature and thermochemical erosion rate raise first and then reduce as aluminum content increases. The mechanical erosion is mainly distributed in the convergent section, and it raises with the increase of aluminum content. When aluminum content is up to 38 %, the maximum mechanical and thermochemical erosion rates are 0.09185 mm/s and 0.0976 mm/s, respectively. This reveals that effects of mechanical erosion on hybrid rocket nozzles should be carefully considered and evaluated under conditions of high aluminum content.

中文翻译：

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混合火箭发动机碳基喷嘴热化学侵蚀和机械侵蚀的实验和数值研究

为了增强混合火箭发动机中推进剂的能量特性，在固体燃料中添加了铝颗粒。然而，这些颗粒可能会导致喷嘴机械腐蚀，从而显着影响电机性能。本文拟研究铝金属化燃料混合火箭发动机中碳基喷嘴的热化学和机械侵蚀机理。进行燃烧测试，使用 95% 过氧化氢和含铝颗粒的端羟基聚丁二烯燃料。实验结果表明，许多金属颗粒从喷嘴中喷出，并且氧化铝大量沉积在喷嘴内表面上。建立了两相流、铝金属化燃料燃烧、热化学烧蚀反应和机械侵蚀耦合的数值计算方法。燃烧室压力和喉道侵蚀率数值计算与试验结果的误差分别为0.53%和7.76%。模拟结果表明，随着铝含量的增加，喷嘴壁压逐渐增大，而H2O、CO、OH和O的质量分数下降。随着铝含量的增加，喷嘴壁温和热化学侵蚀速率先升高后降低。机械侵蚀主要分布在收敛段，且随铝含量的增加而增大。当铝含量达到38%时，最大机械和热化学侵蚀速率分别为0.09185 mm/s和0.0976 mm/s。这表明，在高铝含量的条件下，应仔细考虑和评估机械腐蚀对混合火箭喷嘴的影响。