同軸燃料噴流の三次元渦構造の発達

概要

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We study the transition mechanism governing the three-dimensional evolution of a coflowing fuel jet by means of HSMAC simulations which can handle the density change. In the purely axisymmetric case without any perturbations, calculations provide only Kelvin-Helmholz-type vortices. The spatial and temporal calculations triggered by an azimuthal perturbation, however, provide a detailed picture of orderly three-dimensional transition processes leading to the concentration. reorientation, and stretching of the vorticity. Furthermore, the azimuthal vorticity shows the helical structure in the braid region of vortex rings. The streamwise vorticity, which indicates azimuthally several pairs of vortices with opposite rotation, is produced in the braid region immediately upstream of the core of vortex ring. The streamwise vorticity is stretched in the braid region under the tension of vortex ring, penetrates inside the downstream core, wraps round the upstream core and finally connects each core. The streamwise vortices with opposite rotation induce the radial ejection flow.
一般社団法人日本機械学会の論文
1997-04-25