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Acta Armamentarii ›› 2018, Vol. 39 ›› Issue (9): 1692-1700.doi: 10.3969/j.issn.1000-1093.2018.09.004

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Numerical Simulation of the Influence of Boundary Shape on the Expansion Stability of Four Combustion-gas Jets

FENG Bo-sheng, XUE Xiao-chun   

  1. (School of Energy and Power Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)
  • Received:2018-01-09 Revised:2018-01-09 Online:2018-10-25

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

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