关键词: 水下固体火箭发动机;推力特性;压力脉动;颈缩与胀鼓;多相流

Abstract: To investigate the pressure pulsation characteristics of underwater supersonic jet flow field and the force characteristics on the floating mine， based on the VOF （Volume of fluid） multiphase flow model， a numerical model of supersonic gas jet under different working conditions（under-expansion， full-expansion， over-expansion） was established to study force characteristics on the floating mine. The results show that under the under-expansion condition， the thrust of the engine is gentle and the average thrust is about 12.2kN， and the force on the floating mine has never been negative. Under the full-expansion condition， the positon where necking and bulging of the gas jet occur is far away from the mine body， which weakens violently thrust oscillation of the engine and the vibration of the force on the shell of the floating mine. Under the over-expansion condition， the positon where necking and bulging of the gas jet occur is close to the nozzle， and the thrust of engine pulsates violently， generating 21.7% of the oscillation amplitude. When bulging occurs， the pressure in the flow field significantly reduces， which reduces the force on the rear body of the floating mine， and increases the resistance of the shell. The maximum negative thrust of the floating mine is 27kN.

Key words: Underwater solid rocket motor;Characteristics of thrust;Pressure oscillation;Breaking and bulging;Multiphase flow