Particle Deposition And Segmentation Particle Scouring Of Segmented Solid Rocket Motors

The causes of much slag on the segmented solid rocket motor(SRM)aft combustion chamber wall and particle erosion traces on nozzle divergent section were explored by means of numerical simulation,and the corresponding improvement suggestions were put forward.Typical segmented SRM slag characteristics was analyzed.The effects of Al2O3 particle size distribution,particle-wall impingement models,and inhibitor design parameters on slag were explored.And the suggestion to reduce slag was put forward.Effects of turbulence models and particle tracking models on particle erosion were compared.Two-phase flow features of nozzle divergent section were analyzed.The diameter of particles contributing to erosion marks was estimated.The time interval of particle erosion was judged.And the improvement solution of nozzle profile was put forward.The main conclusions are as follows:(1)According to the Weber based impingement model,main case of particle impingement is adhere,and the slag site is mainly the aft combustion chamber wall.In the particle diameter range of 10?m~120?m,and average particle diameter range of 20?m~70?m,the slag rate on aft combustion chamber wall increases with the decrease of the particles mean diameter,and the slag rate on lower submerged nozzle wall decreases with the decrease of the particles mean diameter.For the internal flow field geometry model at 120 s,when setting the height of inhibitor 0mm~297mm,the probability of particles impinging on aft combustion chamber wall increases because of higher inhibitor,causing larger slag rate on aft combustion chamber wall.(2)The main reason of excessive slag on segmented SRM aft combustion chamber is inhibitor's influence on flow field.To reduce slag,inhibitor material should be reasonably selected to reduce its exposed height in flow field.The burn rates of front and aft combustion chamber grains should be guaranteed the same in grain development and production to make sure grains burn out simultaneously during SRM working process,inorder to avoid aft combustion chamber wall exposed to flow field early.(3)Particle erosion traces on nozzle divergent section appear before 15 s during the SRM working process,and are mainly caused by the particles among aft-fin combustion products ranging from 10?m to 16?m.Reducing the curvature change of nozzle divergent section and increasing the outlet angle of nozzle divergent section could weaken particle erosion effectively.The main innovations include: For slag calculation of segmented SRM,the comparative study of different particle-wall impingement models was carried out for the first time;and the influence of inhibitor height and axial position on slag were analyzed for the first time.