关键词: 火箭发动机, 导弹, 超声速, 非定常流动, 计算流体力学

Abstract:

The phenomenon of hot gas exhausted from the rocket engine flowing into the control section in the burnout phase of a rocket engine is studied using computational fluid dynamics (CFD) method. A simplified simulation method is proposed without much loss in accuracy after analyzing the parameters of the actual trajectory of a missile, based on the aerodynamic theory that disturbance in supersonic flow will not propagate upstream, and it greatly reduce the time cost. The dynamic progress that the air in the control section is first pumped out and the hot gas is sucked in afterward recurred, and flow mechanism is found out: during the working stage of the rocket engine, the air in the control section is pumped out due to the low pressure at the base of the missile, and then along with the reduction in the total pressure in the combustion chamber during the descending stage of the rocket the Mach disk moves towards the base which results in the increase of the base pressure, and finally the hot gas flows into the control section which causes the burning of the circuit board and then the fracture of the missile in the end. Finally the cause of failure is revealed, and the improvement measures and detection method are proposed and then validated in flight tests, the reliability of thermal protection is solved.

Key words: rocket motors, missile, supersonic, unsteady flow, computational fluid dynamics