Two-phase gas-liquid flow field in the underwater ignition process of solid rocket motor was numerically solved by using FLUENT software

turbulence model and VOF (volume of fluid) model. The flow process of gas and the development process of gas bubble at the beginning of ignition were analyzed.The distribution of gas density

pressure and temperature in the wake flow field was numerically simulated. The study showed that:at the beginning of ignition

a complete shock wave was established in the nozzle

after which the mechanism of shock wave was destroyed.No continuous expansion-compression waves were formed because of the gas was affected by pressure disturbances;the gas bubbles head was kept at a large diameter

and the middle gas channel had a periodic expansion-contraction;the parameters had different degrees of shock phenomenon:the wake flow field of the gas density greatly changed at the exit of nozzle with the reason for compression of the water and the increasing quality of gas; the total pressure of the outlet of the nozzle was drastically compressed by the water environment

forming a high pressure zone at the exit of the nozzle; the gas temperature reduced to 1750K or less gradually after three cycles of change.