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通过对几种不同结构形式的爆震发生器进行数值模拟,研究了激波聚焦和火焰聚心现象、气动特性及其机理。数值计算采用多组分理想气体详细的化学反应机理、二维轴对称非定常流动Navier-Stokes方程来模拟流体动力学和化学动力学过程。数值计算表明用较低的点火能量对射流火焰燃烧器中可燃混合物点火,层流火焰在狭窄管壁作用下加速,射流火焰在轴线上汇聚过程有利于激波的加强,强激波加速火焰,在多重激波与火焰反复作用下,激波和火焰面之间出现热点,热点迅速放大并形成压力很高的过驱爆震波,而后衰减为稳定的爆震波,不同的激波聚焦腔爆震波的形成过程不同。通过对数值计算的结果进行分析,得到了起爆距离和稳定爆震距离,为进一步试验提供参考。
By simulating several kinds of detonation generators with different structures, the phenomena of shock focusing and flame centroid, aerodynamic characteristics and their mechanism were studied. The numerical calculation uses the detailed chemical reaction mechanism of multi-component ideal gas and the two-dimensional axisymmetric unsteady flow Navier-Stokes equations to simulate the fluid dynamics and chemical kinetics. The numerical calculation shows that igniting the combustible mixture in the jet flame combustor with lower ignition energy accelerates the laminar flow flame under the action of the narrow tube wall. The converging process of the jet flame on the axis is beneficial to the strengthening of the shock wave. The strong shock accelerates the flame, Under the action of multiple shocks and flames, the hot spots appear between the shock and the flame surface, and the hot spots rapidly enlarge and form overpressurized overdrive detonation waves, which then attenuate into stable detonation waves. Different shock focus chamber detonation waves The formation of different processes. By analyzing the numerical results, the detonation distance and the stable detonation distance are obtained, which can provide reference for further testing.