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为研究水下高速射流气泡变化规律,采用VOF(Volume of Fluids)模型分别对水下等温高速气体射流和热高速气体射流动态流场进行了气水耦合数值求解。其中热射流考虑了汽化因素对气泡内气流场的影响,数值模拟了气泡的形成、发展、断裂及融合过程,揭示了气泡中压力和马赫数等参数的变化规律,得出了水下点火初期的流场特征。研究发现:在相同入口压力下,热射流产生气泡的空间尺度比等温射流产生的气泡空间尺度要小;气泡发展过程中会出现颈缩,也可能断裂,断裂与否取决于气泡颈缩处内外压差,气泡的颈缩与断裂是产生压力脉动的重要因素,并决定了压力峰的位置和大小,气泡断裂位置越靠近喷管出口,压力峰值越大,该压力峰值会影响火箭发动机尾流场特性。
In order to study the variation law of the bubbles in a high-speed underwater jet, a VOF (Volume of Fluids) model is used to solve the dynamic flow field of the high-velocity gas jet and the high-velocity jet. The heat jet considers the influence of vaporization factors on the gas flow in the bubble. The bubble formation, development, fracture and fusion process are numerically simulated. The variation regularity of pressure and Mach number in the bubble is revealed. The flow field characteristics. The results show that at the same inlet pressure, the space scale of bubble generated by thermal jet is smaller than the bubble space scale generated by isothermal jet. During the development of bubble, necking, rupture and fracture may occur depending on the inside and outside of bubble neck The pressure drop and the necking and rupture of bubble are the important factors of pressure pulsation and determine the location and size of the pressure peak. The closer the position of the bubble rupture to the nozzle exit, the greater the pressure peak, the pressure peak will affect the rocket engine wake Field characteristics.