固体火箭发动机碳基材料喷管机械侵蚀特性

为研究碳基材料喷管的机械侵蚀特性,基于两相流理论和经验公式,考虑液滴的蒸发与反应,建立了二维轴对称碳基材料喷管机械侵蚀计算模型.针对15-lb BATES发动机喷管进行了机械侵蚀计算,研究了液滴轨迹、机械侵蚀情况的分布规律,以及推进剂中Al质量分数和燃烧室压强对机械侵蚀的影响.结果表明:机械侵蚀率计算最大值为55μm/s,在实验结果范围内.Al/Al₂O₃混合液滴是机械侵蚀的主要因素,Al液滴由于蒸发氧化而不对壁面造成碰撞.机械侵蚀发生在喷管收敛段,峰值位于喉部上游入口处,喉部和扩张段无机械侵蚀现象.推进剂中Al质量分数增加对机械侵蚀率无显著规律性影响.机械侵蚀率随燃烧室压强的增加呈超线性增长. 

Mechanical erosion characteristics of carbon-based nozzlein solid rocket motor

Based on two-phase flow theory and empirical formula, a two-dimensional axisymmetric carbon-based nozzle model was established to investigate the mechanical erosion characteristics, with consideration of evaporation and reaction of droplets. Results obtained from computations with distributions of droplets trajectories and mechanical erosion were described for the 15-lb BATES engine nozzle. The effects of Al mass fraction of propellant and chamber pressure on mechanical erosion were investigated. Results show that the calculated result of maximum mechanical erosion rate is 55μm/s, which falls within the range of experimental results. Al/Al₂O₃ mixed droplet is the main factor of the mechanical erosion, Al droplets cannot hit the nozzle wall due to rapid evaporation and oxidation. The erosion occurs in the nozzle convergent section, with the peak located upstream the throat, while no mechanical erosion exists in throat and expand zone. The increasement of Al mass fraction shows no significant regularity effect on the mechanical erosion rate. The erosion rate has a superlinear relationship with the chamber pressure.