近场水下爆炸过程中气泡脉动与射流载荷特性研究

Research on bubble pulsation and jet loading characteristics during a near-field underwater explosion

为了深入研究近场水下爆炸过程中产生的气泡射流现象,本文开展了小当量TNT在固支方板底部爆炸的水下爆炸试验,设计了一种阵列式壁压传感器的方法成功测得了气泡射流的载荷时程曲线.实验结果指出,固支方板底部中心处气泡脉动压力峰值与射流压力峰值相差不大,但射流压力持续时间为气泡脉动压力的21.36倍,气泡脉动压力及其持续时间随着传感器距中心位置距离的增加只是略有衰减,而射流压力及持续时间随着传感器距中心位置距离的增加衰减较快,说明射流载荷作用范围较为集中.接着通过Abaqus软件开展了从炸药起爆到气泡射流形成全过程的数值模拟工作,模拟得到的气泡演化过程和气泡射流载荷时程曲线与实验结果基本一致.最后通过数值模拟得到了近场水下爆炸气泡脉动过程中气泡射流比冲量分布规律、气泡射流形态演变规律和气泡射流头部速度变化规律.本文的工作能够为利用近场水下爆炸气泡射流对水面舰艇结构实施毁伤打击提供依据.

To deeply study the bubble jet phenomenon occurring during the near-field underwater explosion,this study performed an underwater explosion test of small equivalent TNT exploding at the bottom of a clamped square plate.The load timehistory curve of the bubble jet was successfully measured by the method employing an array wall pressure sensor.The experimental results show that the peak value of the bubble pulsation pressure at the bottom center of the clamped square plate is not significantly different from the peak value of the jet pressure.However,the duration of the jet pressure is21.36 times that of the bubble pulsation pressure.The bubble pulsation pressure and its duration slightly attenuate,while the jet pressure and its duration attenuate faster with the increasing distance from the sensor to the center,indicating a quite concentrated range of jet load.Further,the numerical simulation of the whole process from the explosion to the bubble jet formation was performed via the Abaqus software.The bubble evolution process and the bubble jet load timehistory curve obtained by the simulation are consistent with the experimental results.Finally,the distribution law of the specific impulse of the bubble jet,the evolution law of the bubble jet shape,and the change law of the head speed of the bubble jet during the near-field underwater explosion bubble pulsation process are obtained through numerical simulation.This work can provide a basis for the destructive strike of surface ship structures using bubble jets formed by a near-field underwater explosion.