Application study of plug nozzles for solid rocket motors

Three types of annular plug nozzles applied to solid rocket motors were compared and annular tile-shaped plug nozzle was considered to be practicable. Taking solid rocket motor nozzles working at high altitude as an example, an 8-unit annular plug nozzle and a bell-shaped nozzle were design. Under the same dimensional condition, the area ratio of plug nozzle is much larger than that of bell-shaped nozzle. Flow field and performance of tile-shaped plug nozzle were investigated by using numerical simulation method and flow field characteristics and pressure distribution along plug cone surface were analyzed. The results show that vacuum efficiency of annular plug nozzles is 78.63% when its efficiency of design point is 97.41%. Its vacuum efficiency is almost 2.0% higher than one dimensional desired vacuum efficiency of bell-shaped nozzle.