Abstract: A simple model was proposed to study the flows in the Laval nozzle under water. Numerical simulations show that there are power law relations for the obstruction mass flows Δ Q and the obstruction interval Δ t with the throat area A t of nozzle: Δ Q ∝ A 1.5 t ,Δ t ∝ A 0.5 t , and with the difference between the stagnant pressure p 0 and the local static pressure: Δ Q andΔ t ∝｛[ p 0-( p 1+ ρ w gH )]/ ρ w ｝ -0.76 when only changing the depth H . It is reasonable that the obstruction is stronger when increasing the depth H . Nevertheless, the obstruction can be decreased by decreasing the throat area A t, or increasing ratio of exit to throat areas A b/ A t or increasing stagnant pressure p 0.

Key words: Submarime launched missle;Underwater firing:Nozzle flow;Mathematical Simulation.

摘要： 针对导弹水下发射时喷管的气体流动问题 ,建立了水下喷管流的简化模型 ,定性地研究水环境的惯性对水下喷管内气体流动造成的阻滞作用。计算显示受阻滞流量ΔQ及受阻滞时间Δt和喷管的喉部面积At 呈幂函数关系 ,固定其他参数仅改变水深 ,ΔQ及Δt和进口处气体的滞止压力p0 与当地水下静压之间的压力差也有幂函数关系。结果表明喷管所处的水下深度越大 ,喷管内气体流动受阻滞状况也就越严重 ,而减小喉部面积At 和适当增加膨胀比Ab/At 以及增加滞止压力p0 ,均有助于改善水环境对喷管喷出气体造成的阻滞状况。

关键词: 潜射导弹;水下点火;喷管气流;数学仿真