烟火药水下燃烧气泡的实验研究

Experimental Study of Bubble Evolution Produced by Pyrotechnic Composition Underwater Combustion

为探讨烟火药水下燃烧的声辐射机理,基于气泡的瞬时性,采用高速摄影和录像的方法对烟火药水下燃烧气泡的整个物理过程进行了试验研究。发现烟火药水下燃烧过程可分为气泡形成、上浮、破裂成气泡云以及气泡云的水面破裂喷涌四个阶段。随着燃烧速度的增加,气泡演变更加剧烈,出现了合并现象,同时所辐射的噪声也随之增大。气泡上升的过程中并不是完整的球形,且总体上由于气泡体积的变化受力不均而呈曲线形上升。

In order to investigate the acoustic radiation mechanism for pyrotechnic composition underwater combustion, the whole evolution process of bubble produced by the underwater combustion was experimentally studied based on the means of high speed photography and video due to its instantaneity. It is found that this combustion process can be obviously divided into four stages, i.e. bubble formation, bubble floating upward, bubble swarm formation of the breaking bubble and spout or splash on the water surface. The bubble evolution becomes more intense and bubble incorporation appears along with the increase of combustion velocity, meanwhile the radiation noise is also increased. In the whole rising process, bubble does not present a perfect sphericity and rises curvilinearly due to its volume change that results in uneven pressure acted on it.