水下超声速燃气喷流形态及流场结构研究

Study on Shapes and Flow Field Structures of Underwater Supersonic Gas Jets

摘要:

高温高压超声速燃气喷入水中的流动过程是一个复杂物理现象，在气液相界面不仅存在着明显的燃气和水的运动速度差，还存在剧烈的相变现象。基于多相流 MIXTURE 模型，建立了考虑高温效应的非平衡相变模型，对水下超声速燃气喷流形态变化规律及流场激波结构、压力演化、气汽液界面非稳态特性影响机理进行了研究。数值结果表明，喷流向下游发展的过程中不断与周围水流场相互作用并发生动量交换， 对喷流形态和流动现象影响很大，射流出现周期性颈缩振荡阶段。在小背压条件下，射流核心的组分基本都是燃气几乎不含水，高温射流的边缘处较容易产生相变；随着背压的增大，水蒸汽主要分布于射流中后部和膨胀气团中。

Abstract:

The flow of high temperature and high pressure supersonic jet entering water is a complex physical process. There is not only an obvious velocity difference between gas and water at the gas-liquid interface，but also a sharp phase transition phenomenon. Based on the multiphase flow MIXTURE model，a non-equilibrium phase transition model considering the high temperature effect is established to study the change law of underwater supersonic gas jet morphology，the impact mechanism of flow field shock structure，pressure evolution，and the unsteady characteristics of the gas vapor-liquid interface. The results show that the jet continuously interacts with the surrounding flow field and exchanges momentum in the process of developing downstream，which has a great impact on the jet morphology and flow phenomenon，and the jet appears regular periodic necking oscillation stage. Under the condition of small back pressure，the components of the jet core are basically gas，and the phase transition is easy to occur at the edge of the high-temperature jet. With the increase of back pressure，water vapor is mainly distributed in the middle and rear of the jet and in the expansion air mass.