Numerical study of chain-reaction implosions in a spatial array of ceramic pressure hulls in the deep sea using a compressible multiphase flow model

Abstract

Ceramic pressure hull arrays, which are core components in providing buoyancy to underwater vehicles, are at risk of chain-reaction implosions in deep-sea environments. This study establishes a numerical model for the chain-reaction implosions of ceramic pressure hull arrays. The model is based on the theory of compressible multiphase flow. The structural finite element method combined with the ceramic material failure criterion is used to determine the cause of chain-reaction implosions. Adaptive mesh refinement is adopted to capture the gas–liquid interface accurately. The accuracy of the numerical simulation method for compressible multiphase flow is verified through an implosion experiment involving a single ceramic pressure hull. Subsequently, the simultaneous implosions of an array of ceramic pressure hulls are calculated and investigated. Finally, the chain-reaction implosions of an array of ceramic pressure hulls are calculated using the proposed model. The propagation of the implosion shockwaves and the implosion flow field distribution are analyzed and compared with those of the simultaneous implosion case. The pressure reduction in the flow field caused by the expansion waves of the implosion is found to cause the chain-reaction implosion of neighboring ceramic pressure hulls. In the chain-reaction process, the air converges at the array center, and the implosion shockwaves converge toward the center and overlap, resulting in the largest-amplitude implosion shockwave occurring near the center of the array. This phenomenon is named the converging effect of chain-reaction implosions.