| Submerged gas jet is a complex two-phase flow, which has a wide range of applications in engineering, metallurgy, defense and other areas. In recent years, with the application of concentric canister launch and the present of water piercing missile launcher, the study of submerged gas jet is highly valued. However, studies on the submerged gas jet nozzle more concentrated in nozzle with circular cross section and supersonic conditions, the study of nozzle with annular section and bubble flow in submerged gas jets need further research.This paper mainly uses the method of numerical simulation to study the gas jet shape. The main research contents and the work includes:(1) building a suitable numerical simulation model to analyze the cylindrical and the annular underwater gas jet.(2) doing numerical simulation studies for the cylindrical and the annular underwater gas jet in different flow velocity.(3) analyzing the development process of the two different forms of underwater gas jet, comparing the similarities and differences between the two different forms of underwater gas jet. The numerical simulation results show that:(a) Two kinds of nozzles to generate bubbles are similar in the development process; the annular jet can develop ring type structure bubble at low gas velocity, which is different from the spherical bubble appears in cylindrical jet; the annular jet is affected by the external environment more obviously;(b) the fight back phenomenon began to appear under the transonic condition. With the increase of jet velocity, the frequency of fight back phenomenon increases.In this paper, the research is the basic of submerged gas jet, it lays the foundation of further studies of submerged gas jet. |
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