水下点火推进尾空泡振荡的研究

本文通过对水下航行体垂直发射出筒后尾空泡内点火推进过程的数值模拟研究,获得了其尾空泡演化的一般规律,并与相应的试验结果进行了对比;进而给出了燃气尾空泡周期性地膨胀、颈缩、阻滞、脱落的演化规律,以及与尾空泡内的压力振荡、喷管扩张段内激波前后移动的相关性。研究表明:水下航行体尾空泡内点火与空中点火、水中直接点火形成的燃气射流存在明显差别,水下点火推进同时会形成对水下航行体额外的振动激励;尾空泡收缩阶段,亚音速射流在尾空泡颈缩处膨胀加速,使尾空泡持续颈缩进而形成对燃气的阻滞作用,是形成尾空泡近似周期性形态演化、空泡压力剧烈振荡的主因。

Research on the pressure oscillation process of tail bubble of underwater igniting propulsion

Based on the numerical simulation,the underwater igniting propulsion process upon vertical launching of an underwater vehicle was studied.Results of both the simulation and the experiment under same conditions were compared.The tail bubble’s periodic morphological evolution of expanding,necking,blocking,and shedding was obtained.The correlation between the tail bubble’s pressure oscillation,morpho?logical evolution and gas dynamics flow structure was also studied.The differences between rocket propul?sions in air and water,between the moments of ignition with and without bubbles in water were pointed out.Additional vibration would be generated in the underwater igniting propulsion process.The block effect in the necking position of tail bubble is the main cause of tail bubble’s pressure oscillation and morphological evolution.