In order to explore the effect of the aspect ratio of rectangular tube on the propagation of the spinning detonation under the limiting detonation propagating conditions, the structure of the three-dimensional gas-phase spinning detonation wave and its propagation modes in rectangular cross-section tubes are numerically investigated based on Euler equations with a 5th-order WENO finite difference scheme and the two-step global reaction model. A linear stability theory of planar detonation wave based on the normal mode method is firstly adopted to examine the chemical reaction parameters for numerical simulations and then several cases with different aspect ratios in cross-section of rectangular tube are investigated to study the structure and propagation mode of three-dimensional gaseous spinning detonation waves. By recording motions of triple lines, flow-field distributions and high-pressure imprint of detonation wave under different sizes of tube cross-section, the effect of cross-sectional geometry on the stable propagation of gaseous detonation under the limiting detonation propagating condition is revealed. The results show that the spinning detonation propagation can be maintained within a certain range of small tube cross-section size, through the movements of horizontal and vertical triple lines and an oblique triple line that is produced by interaction between both horizontal and vertical triple lines. For a square tube with 1 of aspect ratio in cross-section, the high-pressure imprint of spinning detonation on the wall forms the helical strip pattern. With the increase of the aspect ratio of the cross-section size of the tube, the pattern of a high-pressure imprint formed by the spinning detonation on the channel wall varies from the strip structure to a dotted distribution structure, the trajectory of the oblique triple line on the wave front gradually develops from the circular motion in a single direction to a complex trajectory with varying direction. When the aspect ratio is further increased, there is a tendency for the three-dimensional spinning detonation wave to eventually degenerate into a two-dimensional single-head detonation wave structure.
关键词
螺旋爆轰/矩形管道/三波线/两步总包反应
Key words
spinning detonation/rectangular tube/triple line/two-step global reaction
维普
万方数据