关键词: 4股燃气射流, Taylor扩展特性, 湍流掺混, 数值模拟

Abstract: The influence of boundary shape on the expansion stability of four combustion-gas jets under cold conditions is discussed to study an approach to improve the combustion stability of bulk-loaded liquid propellant gun. High-speed digital video recording system is used to record the expansion process of four combustion-gas jets in a five-stage cylindrical stepped-wall type observation chamber. On this basis, a three-dimensional unsteady mathematical model of gas-liquid interaction is established to simulate the expansion processes of four combustion-gas jets in a five-stage cylindrical stepped-wall type, conical and cylindrical observation chambers. The three-dimensional two-phase distribution chart, pressure and temperature distribution chart of jet field were obtained. The results show that the simulated results of axial displacements of four combustion-gas jets in the five-stage cylindrical stepped-wall type chamber coincide well with the experimental results. Both the cylindrical stepped-wall type chamber and the conical chamber can enhance the radial expansion of combustion-gas jet and effectively suppress Taylor cavity and Helmholtz instability; due to gradual induction of stepped-wall in the cylindrical stepped-wall type chamber, the temperature field near the nozzle has no severe pulsation and the jet expansion is more stable. Key

Key words: fourcombustion-gasjets, Taylorexpansioncharacteristics, turbulentmixing, numericalsimulation