火箭发动机水下启动过程流场数值模拟研究

Numerical Simulation of Flow Field for Underwater Starting Process of Rocket Engine

利用流体分析软件Fluent对水下火箭发动机启动过程流场进行了仿真。基于压力的求解器,采用了二维双精度解算器和轴对称理想水流场模型;时间采用一阶隐式离散;压力速度修正选用SIMPLE方法;多相流采用VOF模型;湍流模型采用K-epsilon模型,对处于50 m深水中的火箭发动机启动过程中喷管流场、尾流场进行了详细研究,分析了各参数的变化过程对喷管性能的影响。结果表明,对于给定的喷管,当喷管达到了超音速流动之后,马赫数都是确定的,当地的静压和总压成正比;水下火箭发动机轴向压力总体的变化趋势是在振荡中逐渐减少的,最后降低到环境压力;不同时刻轴线上温度的分布规律和速度基本相似。

The underwater starting process of rocket engine was simulated by fluid analysis software Fluent. Two-dimensional double-precision solver, pressure solver and ideal axisymmetric water- flow-field model were used. First-order implicit time discretization was used, and SIMPLE was used in pressure velocity correction method. The VOF model was used to study Multiphase flow, and K-epsilon model was used in turbulence model. Noozle flow field and wake field of the underwater rocket engine working in 50 m deep water were researched in detail, and the effects of change process of parameters on nozzle performance were analyzed. For a given nozzle, Mach number is determined for each place when the nozzle reaches supersonic flow, and the local static pressure is proportional to total pressure. Overall trends of the axial pressure in the underwater rocket engine gradually reduces in the oscillation, and finally down to ambient pressure. Distribution of temperature on axis at different times is substantially similar to temperature.