全海深水下爆炸载荷特性与规律研究
RESEARCH ON LOAD CHARACTERISTICS AND VARIATION LAWS OF UNDERWATER EXPLOSIONS COVERING THE ENTIRE DEPTH SCALE
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摘要: 传统理论模型在计算深水爆炸工况时, 可能因超出其适用范围而出现偏差, 无法满足精度需求. 为了准确研究全海深水下爆炸载荷特性与规律, 本文采用Zhang等提出的将投影坐标系中计算冲击波载荷方法和统一形式的气泡动力学方程相结合的水下爆炸冲击波与气泡载荷计算理论模型. 通过与百米级和千米级水深水下爆炸实验和数值结果进行对比, 验证了该模型计算结果的准确性. 同时, 本文针对水下爆炸冲击波与气泡载荷及其能量分配随水深变化规律进行探究, 发现随着水深H的增大, 冲击波峰值p_sm稍有增加、冲击波衰减时间T_att逐渐减小, 脉动引起的负压作用更明显, 传播至测点处的冲击波能量和气泡能量各自占炸药总能量之比均减小, 装药当量W对传播至测点处冲击波能量占比有影响而对气泡能量占比影响较小, 气泡第一次坍塌再膨胀过程中的声辐射损失减少, 给出拟合公式描述p_sm、T_att、气泡脉动周期T和最大半径R_m与W、H之间的关系. 本文所用水下爆炸冲击波与气泡载荷计算模型可应用于全海深水下爆炸载荷计算, 所得载荷的变化趋势及其拟合公式旨在为深水爆炸与结构抗爆设计提供参考.Abstract: Traditional theoretical models may deviate from the correct results and fail to meet accuracy requirements when calculating underwater explosion at large depth conditions due to exceeding their applicable range. In order to precisely study the load characteristics and variation laws of underwater explosion loads covering the entire depth scale, a theoretical model for calculating underwater explosion shock waves and bubble loads is established by combining the method for calculating shock wave loads in a projection coordinate system with a unified form of bubble dynamics equation proposed by Zhang et al.. The accuracy of the calculation results obtained from the model is well verified by the experimental and numerical results of underwater explosions at depths of hundreds of meters and kilometers previously published. At the same time, this article explores the variation of shock wave and bubble load and energy distribution with water depth in underwater explosions. It is found that with the increase of water depth H, the peak value of shock wave p_sm slightly increases, and the attenuation time of shock wave T_att gradually decreases. The negative pressure caused by pulsation is more obvious, and the proportion of shock wave energy propagating to the measure point and bubble energy decreases. The proportion of shock wave energy propagating to the measure point is related to the charge equivalent W, while the proportion of bubble energy is little affected by W. The acoustic radiation loss during the first collapse and expansion process of bubbles decreases. Fitted functions are given for describing the relations of p_sm, T_att, the pulsation period T and maximum radius R_m of underwater explosion bubbles between W and H. The calculation model of underwater explosion shock wave and bubble load used in this article can be applied to the calculation of underwater explosion load in the entire sea, and the trend of load variation and its fitting formula obtained can provide reference for deepwater explosion and structural anti explosion design.