【作者】 赵保全；

【导师】 张健；

【作者基本信息】 沈阳理工大学 ， 火炮、自动武器与弹药工程， 2009， 硕士

【摘要】 水中运动的物体,当其表面上任意点处的压力达到或接近于水的饱和蒸汽压时,溶解在水中的微气核重新逸出,在运动体表面不断形成充满水和水蒸气的空泡。空泡长度接近或超过物体的长度时称为超空泡。利用超空泡的减阻原理,实现水中兵器速度的突破具有重要意义。文中采用理论分析与数值模拟相结合的方法,对某型号火箭深水炸弹入水中的流固耦合现象进行了分析,把入水弹道划分四个阶段,总结了每个阶段的特点;构建了入水弹道数学模型;利用FLUENT和LS-DYNA两个软件进行了流场分析,得到了该型号火箭深水炸弹在自然空化条件下的一些结论:在标准大气压下,σ=0.107是该型火箭深水炸弹的临界空化数;其空泡分离点位于头部稍后5～7.5cm的圆弧部位处,此位置是固定的,不随空化数的改变而改变:相同空化数下由于速度和环境压力的不同会有不同的空泡尺寸;随着空化数的减小,超空泡在弹体上的长度逐渐增大,总阻力系数逐渐减小,对于该种头型,其减阻能力可以达到52.3%～86.5%;深水炸弹入水的撞击压力,其值大小与入水速度相关,随入水速度的增加而增加;不同速度下,该型深水炸弹入水撞击压力持续时间为200微秒;该型深水炸弹的尾翼,在入水初期,使弹道出现不稳定。更多还原

【Abstract】 As the pressure of minimum point on surface reach or close to the saturated vapor pressure for movement of objects in the water,the bubbles of dissolved in water will re-escape,then they successive form to cavitation bubble that full of water and water vapor.The length of cavitation bubble approach or exceed the length of objects is known as supercavity.Exploit drag reduction principle of supercavity,which have great significance for achieve underwater weapons’ speed breakthrough.This paper analyze fluid-structure interaction phenomenon of enter water for rocket depth bomb use the method of theoretical analysis and numerical simulation combination,and analyze every phenomenon of four phase according to trait of the depth charge entry water and summarize the characteristics of each phase.The model of water entry trajectory is set up.Then, current field is simulated by using the FLUENT software and LS-DYNA software. Several conclusions of natural cavitation can be get for this type depth bomb, and following are main points.At standard presureσ= 0.107 is critical cavitation factor for this type depth bomb.Cavitation bubble separation point fixed at circle position 5～7.5cm later projectile nose,and this position is fixed,not with the cavitation factor change.The size of cavitation bubble is different owing to speed and environment pressure are different for the same cavitation factor.With the decrease in cavitation factor,the length of supercavity is gradually increasing,total resistance coefficient obvious reduce.Skin friction can be reduced 52.3%～86.5% for the this type nose shape.The valve of impingerment pressure for projectile water-entry is relative with velocity,it increase in direct proportion to speed. Impingerment pressure operation on the duration of 200 microseconds In fifferent water-entry speed.The tail of this type of depth bomb makes ballistic instability in the water-entry early.更多还原