喷管对水下爆轰燃气射流过程影响的数值模拟

为了探究不同喷管构型对水下爆轰燃气射流形态与激波传播过程的影响,基于VOF多相流模型,通过求解二维非稳态雷诺时均Navier-Stokes方程分别对无喷管、加装扩张喷管、收敛喷管的爆轰管水下爆轰过程的内外流场进行二维轴对称数值模拟。研究了喷管构型对水下爆轰过程中形成的透射与反射激波的传播特性、爆轰燃气射流形态演化规律等流场特性的影响。计算结果表明:扩张喷管可以加强向下游传播的透射激波沿轴线方向的指向性,而收敛喷管会减弱透射激波的强度,增强向上游传播的反射激波强度。爆轰燃气泡初期轴向和径向发展速度均随着时间逐渐衰减,喷管对燃气泡的轴向尺度影响较小,但收敛喷管能够显著抑制燃气泡的径向尺度。研究结果可为后续水下爆轰推进的工程化应用提供技术支撑。

Numerical Investigation on Influence of Nozzle Configurationon Underwater Detonation Gas Jets

To investigate the effect of different nozzle configurations on the characteristic patterns of underwater detonation gas jet and shock wave propagation process,based on the VOF multiphase model,2-D axisymmetric numerical simulations on the internal and external flow field during the detonation process of a detonation tube with no nozzle,diverging nozzle and converging nozzle were carried out by means of solving unsteady RANS equations. The effects of nozzle configuration on the propagation characteristics of transmitted and reflected shock waves as well as the morphological evolution of detonation gas jet formed therein were studied. The calculation results show that the diverging nozzle is capable of enhancing the directivity of the transmitted shock wave propagating downstream along the axis,while the converging nozzle will weaken the intensity of the transmitted shock wave and enhance the intensity of the reflected shock wave propagating upstream. The initial axial and radial velocities of detonation bubbles gradually attenuate with time,and the nozzle has little effect on the axial dimension of the gas bubble. On the other hand,the converging nozzle can significantly restrain the radial dimension of the gas bubble. Results in this paper can provide technical support for the subsequent engineering application of underwater detonation propulsion.