Characteristics and load reduction method of the deep-sea implosion of the ellipsoidal and egg-shaped pressure hulls

Abstract

Pressure hulls is an essential part of the deep-sea submersible and may implode to emit shock pressure wave. This paper establishes a deep-sea implosion model based on the Eulerian finite element method, and two implosion conditions, ellipsoidal and egg-shaped, are studied. It is found that the pressure load at the gauging point in the long semi-axis direction is always greater than that in the short semi-axis direction when the two models implosion. Introducing the radius ratio β, it is found that the pressure load after the implosion of the two models increases first and then decreases with the increase of β. Then the dimensionless number Ma is introduced to simulate the change of pressure load under implosion in different water depths. It is found that pressure peak Pm∗ decreases by a factor of Ma−0.5 as Ma increases, and the time Tm∗ to reach the pressure peak increases linearly with the rise of Ma. Therefore, the pressure load caused by implosion can be reduced by reasonably selecting the radius ratio of the pressure hull. In addition, the implosion load when a plurality of pressure hulls are arranged together can be reduced by organizing them along the short semi-axis direction.